Add 4.5 compatible MEF

185 files changed, 27081 insertions, 0 deletions

diff --git a/mcs/class/System.ComponentModel.Composition.4.5/.gitignore b/mcs/class/System.ComponentModel.Composition.4.5/.gitignore
new file mode 100644
index 00000000000..270df4cda87
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/.gitignore
@@ -0,0 +1 @@
+*.resources
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/Makefile b/mcs/class/System.ComponentModel.Composition.4.5/Makefile
new file mode 100644
index 00000000000..43377ab9b07
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/Makefile
@@ -0,0 +1,28 @@
+thisdir = class/System.ComponentModel.Composition
+SUBDIRS = 
+include ../../build/rules.make
+
+LIBRARY = System.ComponentModel.Composition.dll
+LIB_MCS_FLAGS = -r:System.dll -r:System.Core.dll -d:CLR40 -resource:$(STRING_MESSAGES) -d:USE_ECMA_KEY,FEATURE_REFLECTIONCONTEXT,FEATURE_REFLECTIONFILEIO,FEATURE_SERIALIZATION,FEATURE_SLIMLOCK -nowarn:219,414
+
+STRING_MESSAGES = Microsoft.Internal.Strings.resources
+
+CLEAN_FILES += $(STRING_MESSAGES)
+
+EXTRA_DISTFILES = \
+	src/ComponentModel/Strings.resx
+	
+VALID_PROFILE := $(filter 4, $(FRAMEWORK_VERSION_MAJOR))
+ifndef VALID_PROFILE
+LIBRARY_NAME = dummy-System.ComponentModel.Composition.dll
+NO_INSTALL = yes
+NO_SIGN_ASSEMBLY = yes
+NO_TEST = yes
+endif
+
+include ../../build/library.make
+
+$(the_lib): $(STRING_MESSAGES)
+
+$(STRING_MESSAGES): src/ComponentModel/Strings.resx
+	$(RESGEN) $< $@
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/README.txt b/mcs/class/System.ComponentModel.Composition.4.5/README.txt
new file mode 100644
index 00000000000..42045da65f2
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/README.txt
@@ -0,0 +1,4 @@
+This directory contains an import of Microsoft's Mananged Extensibility 2 Preview 4
+as downloaded from:
+
+	http://mef.codeplex.com/
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/System.ComponentModel.Composition.dll.sources b/mcs/class/System.ComponentModel.Composition.4.5/System.ComponentModel.Composition.dll.sources
new file mode 100644
index 00000000000..5072270d8f1
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/System.ComponentModel.Composition.dll.sources
@@ -0,0 +1,178 @@
+src/Assembly/AssemblyInfo.cs
+../../build/common/Consts.cs
+
+src/ComponentModel/ContractAdditions.cs
+src/ComponentModel/PlatformWorkarounds.cs
+src/ComponentModel/Strings.Designer.cs
+src/ComponentModel/SuppressMessages.cs
+src/ComponentModel/SuppressMessagesBaselined.cs
+src/ComponentModel/Microsoft/Internal/ContractServices.cs
+src/ComponentModel/Microsoft/Internal/AttributeServices.cs
+src/ComponentModel/Microsoft/Internal/Lock.Reader.cs
+src/ComponentModel/Microsoft/Internal/LazyServices.cs
+src/ComponentModel/Microsoft/Internal/ReflectionInvoke.cs
+src/ComponentModel/Microsoft/Internal/Lock.cs
+src/ComponentModel/Microsoft/Internal/Assumes.cs
+src/ComponentModel/Microsoft/Internal/Assumes.InternalErrorException.cs
+src/ComponentModel/Microsoft/Internal/StringComparers.cs
+src/ComponentModel/Microsoft/Internal/Lock.Writer.cs
+src/ComponentModel/Microsoft/Internal/Requires.cs
+src/ComponentModel/Microsoft/Internal/ReflectionServices.cs
+src/ComponentModel/Microsoft/Internal/GenerationServices.cs
+src/ComponentModel/Microsoft/Internal/Runtime/Serialization/SerializationServices.cs
+src/ComponentModel/Microsoft/Internal/Collections/CollectionServices.cs
+src/ComponentModel/Microsoft/Internal/Collections/WeakReferenceCollection.cs
+src/ComponentModel/Microsoft/Internal/Collections/ReadOnlyDictionaryDebuggerProxy.cs
+src/ComponentModel/Microsoft/Internal/Collections/CollectionServices.CollectionOfObject.cs
+src/ComponentModel/Microsoft/Internal/Collections/EnumerableCardinality.cs
+src/ComponentModel/Microsoft/Internal/Collections/ReadOnlyDictionary.cs
+src/ComponentModel/System/LazyOfTTMetadata.cs
+src/ComponentModel/System/ComponentModel/Composition/PartMetadataAttribute.cs
+src/ComponentModel/System/ComponentModel/Composition/ExceptionBuilder.cs
+src/ComponentModel/System/ComponentModel/Composition/ImportCardinalityMismatchException.cs
+src/ComponentModel/System/ComponentModel/Composition/ExportCardinalityCheckResult.cs
+src/ComponentModel/System/ComponentModel/Composition/MetadataServices.cs
+src/ComponentModel/System/ComponentModel/Composition/MetadataAttributeAttribute.cs
+src/ComponentModel/System/ComponentModel/Composition/CompositionContractMismatchException.cs
+src/ComponentModel/System/ComponentModel/Composition/ChangeRejectedException.cs
+src/ComponentModel/System/ComponentModel/Composition/ExportFactoryOfT.cs
+src/ComponentModel/System/ComponentModel/Composition/CompositionError.cs
+src/ComponentModel/System/ComponentModel/Composition/CreationPolicy.cs
+src/ComponentModel/System/ComponentModel/Composition/AttributedModelServices.cs
+src/ComponentModel/System/ComponentModel/Composition/CompositionExceptionDebuggerProxy.cs
+src/ComponentModel/System/ComponentModel/Composition/ICompositionService.cs
+src/ComponentModel/System/ComponentModel/Composition/ExportServices.DisposableLazy.cs
+src/ComponentModel/System/ComponentModel/Composition/MetadataViewGenerator.cs
+src/ComponentModel/System/ComponentModel/Composition/ConstraintServices.cs
+src/ComponentModel/System/ComponentModel/Composition/ExportLifetimeContextOfT.cs
+src/ComponentModel/System/ComponentModel/Composition/ImportingConstructorAttribute.cs
+src/ComponentModel/System/ComponentModel/Composition/ImportManyAttribute.cs
+src/ComponentModel/System/ComponentModel/Composition/ImportSource.cs
+src/ComponentModel/System/ComponentModel/Composition/MetadataViewProvider.cs
+src/ComponentModel/System/ComponentModel/Composition/ExportAttribute.cs
+src/ComponentModel/System/ComponentModel/Composition/IPartImportsSatisfiedNotification.cs
+src/ComponentModel/System/ComponentModel/Composition/CompositionException.cs
+src/ComponentModel/System/ComponentModel/Composition/ContractNameServices.cs
+src/ComponentModel/System/ComponentModel/Composition/ImportCardinalityMismatchExceptionDebuggerProxy.cs
+src/ComponentModel/System/ComponentModel/Composition/CompositionErrorDebuggerProxy.cs
+src/ComponentModel/System/ComponentModel/Composition/ImportAttribute.cs
+src/ComponentModel/System/ComponentModel/Composition/ExportFactoryOfTTMetadata.cs
+src/ComponentModel/System/ComponentModel/Composition/PartCreationPolicyAttribute.cs
+src/ComponentModel/System/ComponentModel/Composition/PartNotDiscoverableAttribute.cs
+src/ComponentModel/System/ComponentModel/Composition/ExportServices.cs
+src/ComponentModel/System/ComponentModel/Composition/MetadataViewImplementationAttribute.cs
+src/ComponentModel/System/ComponentModel/Composition/ExportMetadataAttribute.cs
+src/ComponentModel/System/ComponentModel/Composition/InheritedExportAttribute.cs
+src/ComponentModel/System/ComponentModel/Composition/ErrorBuilder.cs
+src/ComponentModel/System/ComponentModel/Composition/CompositionResultOfT.cs
+src/ComponentModel/System/ComponentModel/Composition/IAttributedImport.cs
+src/ComponentModel/System/ComponentModel/Composition/CompositionErrorId.cs
+src/ComponentModel/System/ComponentModel/Composition/CompositionResult.cs
+src/ComponentModel/System/ComponentModel/Composition/CatalogReflectionContextAttribute.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/ExportProvider.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/ApplicationCatalog.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/AtomicCompositionExtensions.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/TypeCatalog.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/INotifyComposablePartCatalogChanged.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/AggregateExportProvider.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionBatch.SingleExportComposablePart.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.PartManager.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/AssemblyCatalogDebuggerProxy.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionBatch.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionLock.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/AtomicComposition.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionScopeDefinitionDebuggerProxy.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionContainer.CompositionServiceShim.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.FactoryExport.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.RecompositionManager.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/AssemblyCatalog.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionConstants.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionOptions.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/ComposablePartCatalogChangeEventArgs.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/ComposablePartExportProvider.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionScopeDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionServices.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExtensions.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionContainer.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionService.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.CatalogExport.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.ScopeFactoryExport.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.Traversal.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.DependentsTraversal.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/ScopingExtensions.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportSourceImportDefinitionHelpers.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/DirectoryCatalog.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.ScopeManager.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/ExportsChangeEventArgs.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.IComposablePartCatalogTraversal.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.EngineContext.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/ExportProvider.GetExportOverrides.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.DependenciesTraversal.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/ComposablePartCatalogCollection.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/AggregateCatalog.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.CatalogChangeProxy.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/DirectoryCatalog.DirectoryCatalogDebuggerProxy.cs
+src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.PartCreatorExport.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/SerializableCompositionElement.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/ImportDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartCatalogDebuggerProxy.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartExceptionDebuggerProxy.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/IPartCreatorImportDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/ContractBasedImportDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/ExportedDelegate.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/ICompositionElement.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/Export.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/CompositionElement.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePart.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/CompositionElementExtensions.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/ExportDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/ImportCardinality.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartException.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/PrimitivesServices.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/CompositionElementDebuggerProxy.cs
+src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartCatalog.cs
+src/ComponentModel/System/ComponentModel/Composition/AttributedModel/AttributedExportDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/AttributedModel/AttributedModelDiscovery.cs
+src/ComponentModel/System/ComponentModel/Composition/AttributedModel/AttributedPartCreationInfo.cs
+src/ComponentModel/System/ComponentModel/Composition/Diagnostics/CompositionTraceId.cs
+src/ComponentModel/System/ComponentModel/Composition/Diagnostics/CompositionTraceSource.cs
+src/ComponentModel/System/ComponentModel/Composition/Diagnostics/CompositionTrace.cs
+src/ComponentModel/System/ComponentModel/Composition/Diagnostics/TraceSourceTraceWriter.cs
+src/ComponentModel/System/ComponentModel/Composition/Diagnostics/TraceWriter.cs
+src/ComponentModel/System/ComponentModel/Composition/Diagnostics/SilverlightTraceWriter.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionExtensions.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionProperty.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportingParameter.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionImportDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/LazyMemberInfo.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionParameterImportDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/PartCreatorMemberImportDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionItem.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/GenericSpecializationPartCreationInfo.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionComposablePartDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/PartCreatorExportDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ExportingMember.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMemberExportDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportingItem.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionModelServices.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/GenericServices.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportingMember.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/IReflectionPartCreationInfo.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/DisposableReflectionComposablePart.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionParameter.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionComposablePart.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ExportfactoryCreator.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionItemType.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionType.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionField.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/PartCreatorParameterImportDefinition.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMethod.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportType.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMember.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ExportfactoryCreator.LifetimeContext.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionWritableMember.cs
+src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMemberImportDefinition.cs
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/Assembly/AssemblyInfo.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/Assembly/AssemblyInfo.cs
new file mode 100644
index 00000000000..a1cceccbcd3
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/Assembly/AssemblyInfo.cs
@@ -0,0 +1,62 @@
+//
+// AssemblyInfo.cs
+//
+// Authors:
+//	Marek Safar (marek.safar@gmail.com)
+//
+// Copyright 2011 Xamarin Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+// 
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using System;
+using System.Reflection;
+using System.Resources;
+using System.Security;
+using System.Security.Permissions;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// General Information about the assembly
+
+[assembly: AssemblyTitle ("System.ComponentModel.Composition.dll")]
+[assembly: AssemblyDescription ("System.ComponentModel.Composition.dll")]
+[assembly: AssemblyDefaultAlias ("System.ComponentModel.Composition.dll")]
+
+[assembly: AssemblyCompany (Consts.MonoCompany)]
+[assembly: AssemblyProduct (Consts.MonoProduct)]
+[assembly: AssemblyCopyright("(c) Microsoft Corporation. All rights reserved.")]
+[assembly: AssemblyVersion (Consts.FxVersion)]
+[assembly: SatelliteContractVersion (Consts.FxVersion)]
+[assembly: AssemblyInformationalVersion (Consts.FxFileVersion)]
+[assembly: AssemblyFileVersion (Consts.FxFileVersion)]
+
+[assembly: NeutralResourcesLanguage ("en-US")]
+[assembly: CLSCompliant (true)]
+[assembly: AssemblyDelaySign (true)]
+
+[assembly: AssemblyKeyFile ("../ecma.pub")]
+
+[assembly: SecurityCritical]
+[assembly: AllowPartiallyTrustedCallers]
+[assembly: ComVisible (false)]
+
+
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/AssemblyInfo.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/AssemblyInfo.cs
new file mode 100644
index 00000000000..ca473df0e3b
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/AssemblyInfo.cs
@@ -0,0 +1,26 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Runtime.CompilerServices;
+using System.Security;
+
+#if FEATURE_CAS_APTCA
+[assembly: AllowPartiallyTrustedCallers]
+#endif //FEATURE_CAS_APTCA
+
+#if USE_CUSTOM_KEY
+[assembly: InternalsVisibleTo("System.ComponentModel.Composition.UnitTests, PublicKey=00240000048000009400000006020000002400005253413100040000010001000fc5993e0f511ad5e16e8b226553493e09067afc41039f70daeb94a968d664f40e69a46b617d15d3d5328be7dbedd059eb98495a3b03cb4ea4ba127444671c3c84cbc1fdc393d7e10b5ee3f31f5a29f005e5eed7e3c9c8af74f413f0004f0c2cabb22f9dd4f75a6f599784e1bab70985ef8174ca6c684278be82ce055a03ebaf")]
+[assembly: InternalsVisibleTo("System.ComponentModel.Composition.UnitTestFramework, PublicKey=00240000048000009400000006020000002400005253413100040000010001000fc5993e0f511ad5e16e8b226553493e09067afc41039f70daeb94a968d664f40e69a46b617d15d3d5328be7dbedd059eb98495a3b03cb4ea4ba127444671c3c84cbc1fdc393d7e10b5ee3f31f5a29f005e5eed7e3c9c8af74f413f0004f0c2cabb22f9dd4f75a6f599784e1bab70985ef8174ca6c684278be82ce055a03ebaf")]
+#elif USE_SILVERLIGHT_KEY 
+[assembly: InternalsVisibleTo("System.ComponentModel.Composition.UnitTests, PublicKey=0024000004800000940000000602000000240000525341310004000001000100B5FC90E7027F67871E773A8FDE8938C81DD402BA65B9201D60593E96C492651E889CC13F1415EBB53FAC1131AE0BD333C5EE6021672D9718EA31A8AEBD0DA0072F25D87DBA6FC90FFD598ED4DA35E44C398C454307E8E33B8426143DAEC9F596836F97C8F74750E5975C64E2189F45DEF46B2A2B1247ADC3652BF5C308055DA9")]
+[assembly: InternalsVisibleTo("System.ComponentModel.Composition.UnitTestFramework, PublicKey=0024000004800000940000000602000000240000525341310004000001000100B5FC90E7027F67871E773A8FDE8938C81DD402BA65B9201D60593E96C492651E889CC13F1415EBB53FAC1131AE0BD333C5EE6021672D9718EA31A8AEBD0DA0072F25D87DBA6FC90FFD598ED4DA35E44C398C454307E8E33B8426143DAEC9F596836F97C8F74750E5975C64E2189F45DEF46B2A2B1247ADC3652BF5C308055DA9")]
+#elif USE_ECMA_KEY
+[assembly: InternalsVisibleTo("System.ComponentModel.Composition.UnitTests, PublicKey=00000000000000000400000000000000")]
+[assembly: InternalsVisibleTo("System.ComponentModel.Composition.UnitTestFramework, PublicKey=00000000000000000400000000000000")]
+#elif USE_CODEPLEX_KEY
+[assembly: InternalsVisibleTo("System.ComponentModel.Composition.UnitTests.CodePlex, PublicKey=0024000004800000940000000602000000240000525341310004000001000100616470ad6a034af669d130b58deedb7ad8544920d8a21d95bc5bb535ca673d8a49b228c5163f78f34b8df3b015fc2b99ff45b7536830a596f711b8b09f80b48a4bf20883ee5b97f50462d7e0f33440f024dae7d8f7eaf875b747619f1e772131a24dea9d5f80e5d54d95f0704f78fe84ac4b3774ce17eb00a764c295846d43e3")]
+[assembly: InternalsVisibleTo("System.ComponentModel.Composition.UnitTestFramework.CodePlex, PublicKey=0024000004800000940000000602000000240000525341310004000001000100616470ad6a034af669d130b58deedb7ad8544920d8a21d95bc5bb535ca673d8a49b228c5163f78f34b8df3b015fc2b99ff45b7536830a596f711b8b09f80b48a4bf20883ee5b97f50462d7e0f33440f024dae7d8f7eaf875b747619f1e772131a24dea9d5f80e5d54d95f0704f78fe84ac4b3774ce17eb00a764c295846d43e3")]
+#else
+#error Unknown platform
+#endif
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/CodePlexKey.snk b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/CodePlexKey.snk
new file mode 100644
index 00000000000..5d44ffe878f
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/CodePlexKey.snk
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/ComponentModel.csproj b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/ComponentModel.csproj
new file mode 100644
index 00000000000..bafafb2d6c4
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/ComponentModel.csproj
@@ -0,0 +1,250 @@
+<?xml version="1.0" encoding="utf-8"?>

+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">

+  <PropertyGroup>

+    <ProductVersion>10.0.20729</ProductVersion>

+    <SchemaVersion>2.0</SchemaVersion>

+    <ProjectGuid>{1BBA5101-D4F0-48B8-A5D6-7B23A099DCE3}</ProjectGuid>

+    <ProjectTypeGuids></ProjectTypeGuids>

+    <OutputType>Library</OutputType>

+    <AssemblyName>System.ComponentModel.Composition.CodePlex</AssemblyName>

+    <RootNamespace>Microsoft.Internal</RootNamespace>

+    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>

+</PropertyGroup>

+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">

+    <DebugSymbols>true</DebugSymbols>

+    <DebugType>full</DebugType>

+    <Optimize>false</Optimize>

+    <OutputPath>..\..\build\</OutputPath>

+    <DefineConstants>TRACE;DEBUG;CLR40;USE_CODEPLEX_KEY;FEATURE_LEGACYSURFACEAREA;FEATURE_SERIALIZATION;FEATURE_FILEIO;FEATURE_LEGACYCOMPONENTMODEL;FEATURE_CAS_APTCA;FEATURE_SLIMLOCK;FEATURE_MISSINGCONTRACTARGUMENTVALIDATOR;FEATURE_MISSINGREADONLYDICTIONARY;FEATURE_REFLECTIONCONTEXT;FEATURE_CUSTOMREFLECTIONCONTEXT;FEATURE_INTERNAL_REFLECTIONCONTEXT;FEATURE_REFLECTIONONLY;FEATURE_REFLECTIONEMIT;FEATURE_REFLECTIONFILEIO;FEATURE_ADVANCEDREFLECTION;FEATURE_TRACING;FEATURE_OBSERVABLECOLLECTIONS;FEATURE_ADVANCEDCOLLECTIONS;FEATURE_COMINTEROP;FEATURE_APPDOMAINCONTROL;MEF_FEATURE_MVC;MEF_FEATURE_REGISTRATION;</DefineConstants>

+    <ErrorReport>prompt</ErrorReport>

+    <WarningLevel>4</WarningLevel>

+    <NoWarn>0414;1570;1572;1573;1591;1699;3021</NoWarn>

+  </PropertyGroup>

+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">

+    <DebugType>pdbonly</DebugType>

+    <Optimize>true</Optimize>

+    <OutputPath>..\..\build\ret\</OutputPath>

+    <DefineConstants>TRACE;CLR40;USE_CODEPLEX_KEY;FEATURE_LEGACYSURFACEAREA;FEATURE_SERIALIZATION;FEATURE_FILEIO;FEATURE_LEGACYCOMPONENTMODEL;FEATURE_CAS_APTCA;FEATURE_SLIMLOCK;FEATURE_MISSINGCONTRACTARGUMENTVALIDATOR;FEATURE_MISSINGREADONLYDICTIONARY;FEATURE_REFLECTIONCONTEXT;FEATURE_CUSTOMREFLECTIONCONTEXT;FEATURE_INTERNAL_REFLECTIONCONTEXT;FEATURE_REFLECTIONONLY;FEATURE_REFLECTIONEMIT;FEATURE_REFLECTIONFILEIO;FEATURE_ADVANCEDREFLECTION;FEATURE_TRACING;FEATURE_OBSERVABLECOLLECTIONS;FEATURE_ADVANCEDCOLLECTIONS;FEATURE_COMINTEROP;FEATURE_APPDOMAINCONTROL;MEF_FEATURE_MVC;MEF_FEATURE_REGISTRATION;</DefineConstants>

+    <ErrorReport>prompt</ErrorReport>

+    <WarningLevel>4</WarningLevel>

+    <NoWarn>0414;1570;1572;1573;1591;1699;3021</NoWarn>

+  </PropertyGroup>

+  <PropertyGroup>

+    <SignAssembly>true</SignAssembly>

+    <AssemblyOriginatorKeyFile>CodePlexKey.snk</AssemblyOriginatorKeyFile>

+  </PropertyGroup>

+

+    <ItemGroup>

+    <Compile Include="AssemblyInfo.cs" />

+    <Compile Include="Microsoft\Internal\Assumes.cs" />

+    <Compile Include="Microsoft\Internal\AttributeServices.cs" />

+    <Compile Include="Microsoft\Internal\Collections\CollectionServices.cs" />

+    <Compile Include="Microsoft\Internal\Collections\CollectionServices.CollectionOfObject.cs" />

+    <Compile Include="Microsoft\Internal\Collections\EnumerableCardinality.cs" />

+    <Compile Include="Microsoft\Internal\Collections\WeakReferenceCollection.cs" />

+    <Compile Include="Microsoft\Internal\ContractServices.cs" />

+    <Compile Include="Microsoft\Internal\Assumes.InternalErrorException.cs" />

+    <Compile Include="Microsoft\Internal\GenerationServices.cs" />

+    <Compile Include="Microsoft\Internal\LazyServices.cs" />

+    <Compile Include="Microsoft\Internal\Lock.cs" />

+    <Compile Include="Microsoft\Internal\Lock.Reader.cs" />

+    <Compile Include="Microsoft\Internal\Lock.Writer.cs" />

+    <Compile Include="Microsoft\Internal\Requires.cs" />

+    <Compile Include="Microsoft\Internal\Runtime\Serialization\SerializationServices.cs" />

+    <Compile Include="Microsoft\Internal\StringComparers.cs" />

+    <Compile Include="Microsoft\Internal\ReflectionServices.cs" />

+    <Compile Include="Microsoft\Internal\ReflectionInvoke.cs" />

+    <Compile Include="Strings.Designer.cs">

+      <AutoGen>True</AutoGen>

+      <DesignTime>True</DesignTime>

+      <DependentUpon>Strings.resx</DependentUpon>

+      <CustomToolNamespace>Microsoft.Internal</CustomToolNamespace>

+    </Compile>

+    <Compile Include="ContractAdditions.cs" />

+    <Compile Include="SuppressMessages.cs" />

+    <Compile Include="SuppressMessagesBaselined.cs" />

+    <Compile Include="System\ComponentModel\Composition\AttributedModelServices.cs" />

+    <Compile Include="System\ComponentModel\Composition\AttributedModel\AttributedModelDiscovery.cs" />

+    <Compile Include="System\ComponentModel\Composition\AttributedModel\AttributedPartCreationInfo.cs" />

+    <Compile Include="System\ComponentModel\Composition\AttributedModel\AttributedExportDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\CatalogReflectionContextAttribute.cs" />

+    <Compile Include="System\ComponentModel\Composition\CompositionExceptionDebuggerProxy.cs" />

+    <Compile Include="System\ComponentModel\Composition\Diagnostics\CompositionTrace.cs" />

+    <Compile Include="System\ComponentModel\Composition\Diagnostics\CompositionTraceId.cs" />

+    <Compile Include="System\ComponentModel\Composition\ConstraintServices.cs" />

+    <Compile Include="System\ComponentModel\Composition\CompositionContractMismatchException.cs" />

+    <Compile Include="System\ComponentModel\Composition\CompositionError.cs" />

+    <Compile Include="System\ComponentModel\Composition\CompositionResultOfT.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CatalogExportProvider.FactoryExport.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CatalogExportProvider.PartCreatorExport.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CatalogExportProvider.ScopeFactoryExport.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CatalogExportProvider.ScopeManager.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CompositionContainer.CompositionServiceShim.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CompositionLock.cs" />

+    <Compile Include="System\ComponentModel\Composition\Diagnostics\CompositionTraceSource.cs" />

+    <Compile Include="System\ComponentModel\Composition\Diagnostics\TraceWriter.cs" />

+    <Compile Include="System\ComponentModel\Composition\Diagnostics\TraceSourceTraceWriter.cs" />

+    <Compile Include="System\ComponentModel\Composition\Diagnostics\SilverlightTraceWriter.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\ImportSourceImportDefinitionHelpers.cs" />

+    <Compile Include="System\ComponentModel\Composition\ImportCardinalityMismatchExceptionDebuggerProxy.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\FilteredCatalog.DependenciesTraversal.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\FilteredCatalog.DependentsTraversal.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\FilteredCatalog.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\FilteredCatalog.Traversal.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\FilteredCatalog.IComposablePartCatalogTraversal.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\ScopingExtensions.cs" />

+    <Compile Include="System\ComponentModel\Composition\InheritedExportAttribute.cs" />

+    <Compile Include="System\ComponentModel\Composition\ExportServices.DisposableLazy.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\AtomicComposition.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\AtomicCompositionExtensions.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CompositionConstants.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CompositionOptions.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CatalogExportProvider.CatalogChangeProxy.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\ComposablePartExceptionDebuggerProxy.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CompositionScopeDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CompositionScopeDefinitionDebuggerProxy.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\IPartCreatorImportDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\PrimitivesServices.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ExportfactoryCreator.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ExportfactoryCreator.LifetimeContext.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\GenericServices.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\GenericSpecializationPartCreationInfo.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\PartCreatorExportDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\PartCreatorParameterImportDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\PartCreatorMemberImportDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\IAttributedImport.cs" />

+    <Compile Include="System\ComponentModel\Composition\ImportCardinalityMismatchException.cs" />

+    <Compile Include="System\ComponentModel\Composition\ImportManyAttribute.cs" />

+    <Compile Include="System\ComponentModel\Composition\ErrorBuilder.cs" />

+    <Compile Include="System\ComponentModel\Composition\CompositionErrorDebuggerProxy.cs" />

+    <Compile Include="System\ComponentModel\Composition\ExceptionBuilder.cs" />

+    <Compile Include="System\ComponentModel\Composition\ExportCardinalityCheckResult.cs" />

+    <Compile Include="System\ComponentModel\Composition\ExportFactoryOfT.cs" />

+    <Compile Include="System\ComponentModel\Composition\ExportFactoryOfTTMetadata.cs" />

+    <Compile Include="System\ComponentModel\Composition\ExportLifetimeContextOfT.cs" />

+    <Compile Include="System\ComponentModel\Composition\ExportServices.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\AggregateCatalog.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\AggregateExportProvider.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\AssemblyCatalog.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\AssemblyCatalogDebuggerProxy.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CatalogExportProvider.CatalogExport.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CatalogExportProvider.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CatalogExtensions.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\ComposablePartCatalogChangeEventArgs.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\ComposablePartCatalogCollection.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\ComposablePartExportProvider.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CompositionBatch.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CompositionBatch.SingleExportComposablePart.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CompositionContainer.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CompositionService.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\CompositionServices.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\ExportProvider.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\ExportProvider.GetExportOverrides.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\ExportsChangeEventArgs.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\ImportEngine.RecompositionManager.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\ImportEngine.EngineContext.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\ImportEngine.PartManager.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\ImportEngine.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\INotifyComposablePartCatalogChanged.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\TypeCatalog.cs" />

+    <Compile Include="System\ComponentModel\Composition\ImportingConstructorAttribute.cs" />

+    <Compile Include="System\ComponentModel\Composition\IPartImportsSatisfiedNotification.cs" />

+    <Compile Include="System\ComponentModel\Composition\MetadataServices.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\ComposablePart.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\ComposablePartCatalog.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\ComposablePartCatalogDebuggerProxy.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\ComposablePartDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\ComposablePartException.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\CompositionElement.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\CompositionElementDebuggerProxy.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\CompositionElementExtensions.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\ContractBasedImportDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\Export.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\ExportDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\ExportedDelegate.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\ICompositionElement.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\ImportCardinality.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\ImportDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\Primitives\SerializableCompositionElement.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\DisposableReflectionComposablePart.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\IReflectionPartCreationInfo.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\LazyMemberInfo.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionImportDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionItemType.cs" />

+    <Compile Include="System\ComponentModel\Composition\MetadataViewProvider.cs" />

+    <Compile Include="System\ComponentModel\Composition\MetadataViewImplementationAttribute.cs" />

+    <Compile Include="System\ComponentModel\Composition\PartCreationPolicyAttribute.cs" />

+    <Compile Include="System\ComponentModel\Composition\PartMetadataAttribute.cs" />

+    <Compile Include="System\ComponentModel\Composition\PartNotDiscoverableAttribute.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionExtensions.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ImportingParameter.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ImportingItem.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ExportingMember.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ImportingMember.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ImportType.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionComposablePart.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionComposablePartDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionMemberExportDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionMemberImportDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionModelServices.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionParameterImportDefinition.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionWritableMember.cs" />

+    <Compile Include="System\ComponentModel\Composition\MetadataViewGenerator.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionField.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionMember.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionParameter.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionProperty.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionType.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionItem.cs" />

+    <Compile Include="System\ComponentModel\Composition\ReflectionModel\ReflectionMethod.cs" />

+    <Compile Include="System\ComponentModel\Composition\ChangeRejectedException.cs" />

+    <Compile Include="System\ComponentModel\Composition\CompositionException.cs" />

+    <Compile Include="System\ComponentModel\Composition\CompositionErrorId.cs" />

+    <Compile Include="System\ComponentModel\Composition\CompositionResult.cs" />

+    <Compile Include="System\ComponentModel\Composition\ContractNameServices.cs" />

+    <Compile Include="System\ComponentModel\Composition\CreationPolicy.cs" />

+    <Compile Include="System\ComponentModel\Composition\ExportAttribute.cs" />

+    <Compile Include="System\ComponentModel\Composition\ExportMetadataAttribute.cs" />

+    <Compile Include="System\ComponentModel\Composition\ICompositionService.cs" />

+    <Compile Include="System\ComponentModel\Composition\ImportAttribute.cs" />

+    <Compile Include="System\ComponentModel\Composition\ImportSource.cs" />

+    <Compile Include="System\ComponentModel\Composition\MetadataAttributeAttribute.cs" />

+    <Compile Include="System\LazyOfTTMetadata.cs" />

+    <Compile Include="PlatformWorkarounds.cs" />

+    <Compile Include="Microsoft\Internal\Collections\ReadOnlyDictionary.cs" />

+    <Compile Include="Microsoft\Internal\Collections\ReadOnlyDictionaryDebuggerProxy.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\ApplicationCatalog.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\DirectoryCatalog.cs" />

+    <Compile Include="System\ComponentModel\Composition\Hosting\DirectoryCatalog.DirectoryCatalogDebuggerProxy.cs" />

+  </ItemGroup>

+

+    <ItemGroup>

+    <Compile Include="VersionInfo.cs" />

+    <None Include="CodePlexKey.snk" />

+  </ItemGroup>

+

+    <ItemGroup>

+    <Reference Include="mscorlib" />

+    <Reference Include="System" />

+    <Reference Include="System.Core" />

+    <Reference Include="mscorlib" />

+  </ItemGroup>

+

+    <ItemGroup>

+    <ProjectReference Include="..\InternalReflectionContext\System.Reflection.Context.csproj">

+      <Project>{0900B66B-65A1-4653-B3FD-C9A7E76297F1}</Project>

+      <Name>System.Reflection.Context.CodePlex</Name>

+    </ProjectReference>

+  </ItemGroup>

+

+    <ItemGroup>

+    <EmbeddedResource Include="Strings.resx">

+      <SubType>Designer</SubType>

+      <Generator>ResXFileCodeGenerator</Generator>

+      <LastGenOutput>Strings.Designer.cs</LastGenOutput>

+      <CustomToolNamespace>Microsoft.Internal</CustomToolNamespace>

+    </EmbeddedResource>

+  </ItemGroup>

+

+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />

+</Project>
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/ContractAdditions.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/ContractAdditions.cs
new file mode 100644
index 00000000000..cc3fcddc640
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/ContractAdditions.cs
@@ -0,0 +1,113 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.ComponentModel.Composition.Primitives;
+using System.Linq;
+
+namespace System.Diagnostics.Contracts
+{ 
+#if CONTRACTS_FULL
+    [ContractClassFor(typeof(ComposablePart))]
+    internal abstract class ComposablePartContract : ComposablePart
+    {
+        public override IEnumerable<ExportDefinition> ExportDefinitions
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<IEnumerable<ExportDefinition>>() != null);
+
+                throw new NotImplementedException();
+            }
+        }
+
+        public override IEnumerable<ImportDefinition> ImportDefinitions
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<IEnumerable<ImportDefinition>>() != null);
+
+                throw new NotImplementedException();
+            }
+        }
+
+        public override object GetExportedValue(ExportDefinition definition)
+        {
+            Contract.Requires(definition != null);
+
+            throw new NotImplementedException();
+        }
+
+        public override void SetImport(ImportDefinition definition, IEnumerable<Export> exports)
+        {
+            Contract.Requires(definition != null);
+            Contract.Requires(exports != null);
+
+            throw new NotImplementedException();
+        }
+    }
+
+    [ContractClassFor(typeof(ComposablePartDefinition))]
+    internal abstract class ComposablePartDefinitionContract : ComposablePartDefinition
+    {
+        public override IEnumerable<ExportDefinition> ExportDefinitions
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<IEnumerable<ExportDefinition>>() != null);
+                Contract.Ensures(Contract.ForAll(Contract.Result<IEnumerable<ExportDefinition>>(), e => e != null));
+
+                throw new NotImplementedException();
+            }
+        }
+
+        public override IEnumerable<ImportDefinition> ImportDefinitions
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<IEnumerable<ImportDefinition>>() != null);
+                Contract.Ensures(Contract.ForAll(Contract.Result<IEnumerable<ImportDefinition>>(), i => i != null));
+
+                throw new NotImplementedException();
+            }
+        }
+
+        public override ComposablePart CreatePart()
+        {
+            Contract.Ensures(Contract.Result<ComposablePart>() != null);
+            throw new NotImplementedException();
+        }
+    }
+
+    [ContractClassFor(typeof(ICompositionElement))]
+    internal abstract class ICompositionElementContract : ICompositionElement
+    {
+        public string DisplayName
+        {
+            get 
+            {
+                Contract.Ensures(!string.IsNullOrEmpty(Contract.Result<string>()));
+                
+                throw new NotImplementedException(); 
+            }
+        }
+
+        public ICompositionElement Origin
+        {
+            get { throw new NotImplementedException(); }
+        }
+    }
+
+    [ContractClassFor(typeof(ICompositionService))]
+    internal abstract class ICompositionServiceContract : ICompositionService
+    {
+        public void SatisfyImportsOnce(ComposablePart part)
+        {
+            Contract.Requires(part != null);
+            throw new NotImplementedException();
+        }
+    }
+#endif
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Assumes.InternalErrorException.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Assumes.InternalErrorException.cs
new file mode 100644
index 00000000000..aec196251ca
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Assumes.InternalErrorException.cs
@@ -0,0 +1,32 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Runtime.Serialization;
+
+namespace Microsoft.Internal
+{
+    partial class Assumes
+    {
+        // The exception that is thrown when an internal assumption failed.
+        [Serializable]
+        [SuppressMessage("Microsoft.Design", "CA1064:ExceptionsShouldBePublic")]
+        private class InternalErrorException : Exception
+        {
+            public InternalErrorException(string message)
+                : base(string.Format(CultureInfo.CurrentCulture, Strings.InternalExceptionMessage, message))
+            {
+            }
+
+#if FEATURE_SERIALIZATION
+            [System.Security.SecuritySafeCritical]
+            protected InternalErrorException(SerializationInfo info, StreamingContext context)
+                : base(info, context)
+            {
+            }
+#endif
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Assumes.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Assumes.cs
new file mode 100644
index 00000000000..99f7c643ade
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Assumes.cs
@@ -0,0 +1,79 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Runtime.Serialization;
+
+namespace Microsoft.Internal
+{
+    internal static partial class Assumes
+    {
+        [DebuggerStepThrough]
+        internal static void NotNull<T>(T value)
+            where T : class
+        {
+            IsTrue(value != null);
+        }
+
+        [DebuggerStepThrough]
+        internal static void NotNull<T1, T2>(T1 value1, T2 value2)
+            where T1 : class
+            where T2 : class
+        {
+            NotNull(value1);
+            NotNull(value2);
+        }
+
+        [DebuggerStepThrough]
+        internal static void NotNull<T1, T2, T3>(T1 value1, T2 value2, T3 value3)
+            where T1 : class
+            where T2 : class
+            where T3 : class
+        {
+            NotNull(value1);
+            NotNull(value2);
+            NotNull(value3);
+        }
+
+        [DebuggerStepThrough]
+        internal static void NotNullOrEmpty(string value)
+        {
+            NotNull(value);
+            IsTrue(value.Length > 0);
+        }
+
+        [DebuggerStepThrough]
+        internal static void IsTrue(bool condition)
+        {
+            if (!condition)
+            {
+                throw UncatchableException(null);
+            }
+        }
+
+        [DebuggerStepThrough]
+        internal static void IsTrue(bool condition, [Localizable(false)]string message)
+        {
+            if (!condition)
+            {
+                throw UncatchableException(message);
+            }
+        }
+
+        [DebuggerStepThrough]
+        internal static T NotReachable<T>()
+        {
+            throw UncatchableException("Code path should never be reached!");
+        }
+
+        [DebuggerStepThrough]
+        private static Exception UncatchableException([Localizable(false)]string message)
+        {
+            return new InternalErrorException(message);
+        }
+    } 
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/AttributeServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/AttributeServices.cs
new file mode 100644
index 00000000000..6b9f08b61c8
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/AttributeServices.cs
@@ -0,0 +1,43 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+
+namespace Microsoft.Internal
+{
+    internal static class AttributeServices
+    {
+        public static T[] GetAttributes<T>(this ICustomAttributeProvider attributeProvider) where T : class
+        {
+            return (T[])attributeProvider.GetCustomAttributes(typeof(T), false);
+        }
+
+        public static T[] GetAttributes<T>(this ICustomAttributeProvider attributeProvider, bool inherit) where T : class
+        {
+            return (T[])attributeProvider.GetCustomAttributes(typeof(T), inherit);
+        }
+
+        public static T GetFirstAttribute<T>(this ICustomAttributeProvider attributeProvider) where T : class
+        {
+            return GetAttributes<T>(attributeProvider).FirstOrDefault();
+        }
+
+        public static T GetFirstAttribute<T>(this ICustomAttributeProvider attributeProvider, bool inherit) where T : class
+        {
+            return GetAttributes<T>(attributeProvider, inherit).FirstOrDefault();
+        }
+
+        public static bool IsAttributeDefined<T>(this ICustomAttributeProvider attributeProvider) where T : class
+        {
+            return attributeProvider.IsDefined(typeof(T), false);
+        }
+
+        public static bool IsAttributeDefined<T>(this ICustomAttributeProvider attributeProvider, bool inherit) where T : class
+        {
+            return attributeProvider.IsDefined(typeof(T), inherit);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/CollectionServices.CollectionOfObject.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/CollectionServices.CollectionOfObject.cs
new file mode 100644
index 00000000000..4406ea65047
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/CollectionServices.CollectionOfObject.cs
@@ -0,0 +1,147 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Reflection;
+
+namespace Microsoft.Internal.Collections
+{
+    internal static partial class CollectionServices
+    {
+        public static ICollection<object> GetCollectionWrapper(Type itemType, object collectionObject)
+        {
+            Assumes.NotNull(itemType, collectionObject);
+
+            var underlyingItemType = itemType.UnderlyingSystemType;
+
+            if (underlyingItemType == typeof(object))
+            {
+                return (ICollection<object>)collectionObject;
+            }
+
+            // Most common .Net collections implement IList as well so for those
+            // cases we can optimize the wrapping instead of using reflection to create
+            // a generic type.
+            if (typeof(IList).IsAssignableFrom(collectionObject.GetType()))
+            {
+                return new CollectionOfObjectList((IList)collectionObject);
+            }
+
+            Type collectionType = typeof(CollectionOfObject<>).MakeGenericType(underlyingItemType);
+
+            return (ICollection<object>)Activator.CreateInstance(collectionType, collectionObject);
+        }
+
+        private class CollectionOfObjectList : ICollection<object>
+        {
+            private readonly IList _list;
+
+            public CollectionOfObjectList(IList list)
+            {
+                this._list = list;
+            }
+
+            public void Add(object item)
+            {
+                this._list.Add(item);
+            }
+
+            public void Clear()
+            {
+                this._list.Clear();
+            }
+
+            public bool Contains(object item)
+            {
+                return Assumes.NotReachable<bool>();
+            }
+
+            public void CopyTo(object[] array, int arrayIndex)
+            {
+                Assumes.NotReachable<object>();
+            }
+
+            public int Count
+            {
+                get { return Assumes.NotReachable<int>(); }
+            }
+
+            public bool IsReadOnly
+            {
+                get { return this._list.IsReadOnly; }
+            }
+
+            public bool Remove(object item)
+            {
+                return Assumes.NotReachable<bool>();
+            }
+
+            public IEnumerator<object> GetEnumerator()
+            {
+                return Assumes.NotReachable<IEnumerator<object>>();
+            }
+
+            IEnumerator IEnumerable.GetEnumerator()
+            {
+                return Assumes.NotReachable<IEnumerator>();
+            }
+        }
+
+        private class CollectionOfObject<T> : ICollection<object>
+        {
+            private readonly ICollection<T> _collectionOfT;
+
+            public CollectionOfObject(object collectionOfT)
+            {
+                this._collectionOfT = (ICollection<T>)collectionOfT;
+            }
+
+            public void Add(object item)
+            {
+                this._collectionOfT.Add((T) item);
+            }
+
+            public void Clear()
+            {
+                this._collectionOfT.Clear();
+            }
+
+            public bool Contains(object item)
+            {
+                return Assumes.NotReachable<bool>();
+            }
+
+            public void CopyTo(object[] array, int arrayIndex)
+            {
+                Assumes.NotReachable<object>();
+            }
+
+            public int Count
+            {
+                get { return Assumes.NotReachable<int>(); }
+            }
+
+            public bool IsReadOnly
+            {
+                get { return this._collectionOfT.IsReadOnly; }
+            }
+
+            public bool Remove(object item)
+            {
+                return Assumes.NotReachable<bool>();
+            }
+
+            public IEnumerator<object> GetEnumerator()
+            {
+                return Assumes.NotReachable<IEnumerator<object>>();
+            }
+
+            IEnumerator IEnumerable.GetEnumerator()
+            {
+                return Assumes.NotReachable<IEnumerator>();
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/CollectionServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/CollectionServices.cs
new file mode 100644
index 00000000000..f994098ae0f
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/CollectionServices.cs
@@ -0,0 +1,270 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Linq;
+
+namespace Microsoft.Internal.Collections
+{
+    internal static partial class CollectionServices
+    {
+        private static readonly Type StringType = typeof(string);
+        private static readonly Type IEnumerableType = typeof(IEnumerable);
+        private static readonly Type IEnumerableOfTType = typeof(IEnumerable<>);
+        private static readonly Type ICollectionOfTType = typeof(ICollection<>);
+
+        public static bool IsEnumerableOfT(Type type)
+        {
+            if (type.IsGenericType)
+            {
+                Type genericType = type.GetGenericTypeDefinition().UnderlyingSystemType;
+
+                if (genericType == IEnumerableOfTType)
+                {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        public static Type GetEnumerableElementType(Type type)
+        {
+            if (type.UnderlyingSystemType == StringType || !IEnumerableType.IsAssignableFrom(type))
+            {
+                return null;
+            }
+
+            Type closedType;
+            if (ReflectionServices.TryGetGenericInterfaceType(type, IEnumerableOfTType, out closedType))
+            {
+                return closedType.GetGenericArguments()[0];
+            }
+
+            return null;
+        }
+
+        public static Type GetCollectionElementType(Type type)
+        {
+            Type closedType;
+            if (ReflectionServices.TryGetGenericInterfaceType(type, ICollectionOfTType, out closedType))
+            {
+                return closedType.GetGenericArguments()[0];
+            }
+
+            return null;
+        }
+
+        public static ReadOnlyCollection<T> ToReadOnlyCollection<T>(this IEnumerable<T> source)
+        {
+            Assumes.NotNull(source);
+
+            return new ReadOnlyCollection<T>(source.AsArray());
+        }
+
+        public static IEnumerable<T> ConcatAllowingNull<T>(this IEnumerable<T> source, IEnumerable<T> second)
+        {
+            if (second == null || !second.FastAny())
+            {
+                return source;
+            }
+
+            if (source == null || !source.FastAny())
+            {
+                return second;
+            }
+
+            return source.Concat(second);
+        }
+
+        public static ICollection<T> ConcatAllowingNull<T>(this ICollection<T> source, ICollection<T> second)
+        {
+            if (second == null || (second.Count == 0))
+            {
+                return source;
+            }
+
+            if (source == null || (source.Count == 0))
+            {
+                return second;
+            }
+
+            List<T> result = new List<T>(source);
+            result.AddRange(second);
+
+            return result;
+        }
+
+        public static List<T> FastAppendToListAllowNulls<T>(this List<T> source, IEnumerable<T> second)
+        {
+            if (second == null)
+            {
+                return source;
+            }
+
+            // if there's nothing in the source, return the second
+            if ((source == null) || (source.Count == 0))
+            {
+                return second.AsList();
+            }
+
+            // if the second is List<T>, and contains very few elements there's no need for AddRange
+            List<T> secondAsList = second as List<T>;
+            if (secondAsList != null)
+            {
+                if (secondAsList.Count == 0)
+                {
+                    return source;
+                }
+                else if (secondAsList.Count == 1)
+                {
+                    source.Add(secondAsList[0]);
+                    return source;
+                }
+            }
+            
+            // last resort - nothing is null, need to append
+            source.AddRange(second);
+            return source;
+            
+        }
+ 
+        public static void ForEach<T>(this IEnumerable<T> source, Action<T> action)
+        {
+            foreach(T t in source)
+            {
+                action.Invoke(t);
+            }
+        }
+
+        public static EnumerableCardinality GetCardinality<T>(this IEnumerable<T> source)
+        {
+            Assumes.NotNull(source);
+
+            // Cast to ICollection instead of ICollection<T> for performance reasons.
+            ICollection collection = source as ICollection;
+            if (collection != null)
+            {
+                switch (collection.Count)
+                {
+                    case 0:
+                        return EnumerableCardinality.Zero;
+
+                    case 1:
+                        return EnumerableCardinality.One;
+
+                    default:
+                        return EnumerableCardinality.TwoOrMore;
+                }
+            }
+
+            using (var enumerator = source.GetEnumerator())
+            {
+                if (!enumerator.MoveNext())
+                {
+                    return EnumerableCardinality.Zero;
+                }
+
+                if (!enumerator.MoveNext())
+                {
+                    return EnumerableCardinality.One;
+                }
+
+                return EnumerableCardinality.TwoOrMore;
+            }
+        }
+
+        public static bool FastAny<T>(this IEnumerable<T> source)
+        {
+            // Enumerable.Any<T> underneath doesn't cast to ICollection, 
+            // like it does with many of the other LINQ methods.
+            // Below is significantly (4x) when mainly working with ICollection
+            // sources and a little slower if working with mainly IEnumerable<T> 
+            // sources.
+
+            // Cast to ICollection instead of ICollection<T> for performance reasons.
+            ICollection collection = source as ICollection;
+            if (collection != null)
+            {
+                return collection.Count > 0;
+            }
+
+            return source.Any();
+        }
+
+        public static Stack<T> Copy<T>(this Stack<T> stack)
+        {
+            Assumes.NotNull(stack);
+
+            // Stack<T>.GetEnumerator walks from top to bottom 
+            // of the stack, whereas Stack<T>(IEnumerable<T>) 
+            // pushes to bottom from top, so we need to reverse 
+            // the stack to get them in the right order.
+            return new Stack<T>(stack.Reverse());
+        }
+
+        public static T[] AsArray<T>(this IEnumerable<T> enumerable)
+        {
+            T[] array = enumerable as T[];
+
+            if (array != null)
+            {
+                return array;
+            }
+
+            return enumerable.ToArray();
+        }
+
+        public static List<T> AsList<T>(this IEnumerable<T> enumerable)
+        {
+            List<T> list = enumerable as List<T>;
+
+            if (list != null)
+            {
+                return list;
+            }
+
+            return enumerable.ToList();
+        }
+
+        public static bool IsArrayEqual<T>(this T[] thisArray, T[] thatArray)
+        {
+            if (thisArray.Length != thatArray.Length)
+            {
+                return false;
+            }
+
+            for(int i=0; i< thisArray.Length; i++)
+            {
+                if (!thisArray[i].Equals( thatArray[i]))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        public static bool IsCollectionEqual<T>(this IList<T> thisList, IList<T> thatList)
+        {
+            if (thisList.Count != thatList.Count)
+            {
+                return false;
+            }
+
+            for (int i = 0; i < thisList.Count; i++)
+            {
+                if (!thisList[i].Equals(thatList[i]))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/EnumerableCardinality.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/EnumerableCardinality.cs
new file mode 100644
index 00000000000..b3be71c0f77
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/EnumerableCardinality.cs
@@ -0,0 +1,14 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+
+namespace Microsoft.Internal.Collections
+{
+    internal enum EnumerableCardinality : int
+    {
+        Zero = 0,
+        One = 1,
+        TwoOrMore = 2,
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/ReadOnlyDictionary.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/ReadOnlyDictionary.cs
new file mode 100644
index 00000000000..03269317f54
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/ReadOnlyDictionary.cs
@@ -0,0 +1,106 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics;
+using Microsoft.Internal;
+
+// This is using the desktop namespace for ReadOnlyDictionary, the source code is in Microsoft\Internal\Collections to keep it seperate from the main MEF codebase.
+namespace System.Collections.ObjectModel
+{
+    
+    [DebuggerDisplay("Count = {Count}")]
+    [DebuggerTypeProxy(typeof(ReadOnlyDictionaryDebuggerProxy<,>))]
+    internal sealed partial class ReadOnlyDictionary<TKey, TValue> : IDictionary<TKey, TValue>
+    {
+        private readonly IDictionary<TKey, TValue> _innerDictionary;
+
+        public ReadOnlyDictionary(IDictionary<TKey, TValue> dictionary)
+        {
+            this._innerDictionary = dictionary ?? new Dictionary<TKey, TValue>(0);
+        }
+
+        public int Count
+        {
+            get { return this._innerDictionary.Count; }
+        }
+
+        public bool IsReadOnly
+        {
+            get { return true; }
+        }
+
+        public ICollection<TKey> Keys
+        {
+            get { return this._innerDictionary.Keys; }
+        }
+
+        public TValue this[TKey key]
+        {
+            get { return this._innerDictionary[key]; }
+            set { throw new NotSupportedException(Strings.NotSupportedReadOnlyDictionary); }
+        }
+
+        public ICollection<TValue> Values
+        {
+            get { return this._innerDictionary.Values; }
+        }
+
+        public bool Contains(KeyValuePair<TKey, TValue> item)
+        {
+            return this._innerDictionary.Contains(item);
+        }
+
+        public bool ContainsKey(TKey key)
+        {
+            return this._innerDictionary.ContainsKey(key);
+        }
+
+        public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
+        {
+            this._innerDictionary.CopyTo(array, arrayIndex);
+        }
+
+        public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
+        {
+            return this._innerDictionary.GetEnumerator();
+        }
+
+        public bool TryGetValue(TKey key, out TValue value)
+        {
+            return this._innerDictionary.TryGetValue(key, out value);
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return this._innerDictionary.GetEnumerator();
+        }
+
+        void IDictionary<TKey, TValue>.Add(TKey key, TValue value)
+        {
+            throw new NotSupportedException(Strings.NotSupportedReadOnlyDictionary);
+        }
+
+        void ICollection<KeyValuePair<TKey, TValue>>.Add(KeyValuePair<TKey, TValue> item)
+        {
+            throw new NotSupportedException(Strings.NotSupportedReadOnlyDictionary);
+        }
+
+        void ICollection<KeyValuePair<TKey, TValue>>.Clear()
+        {
+            throw new NotSupportedException(Strings.NotSupportedReadOnlyDictionary);
+        }
+
+        bool IDictionary<TKey, TValue>.Remove(TKey key)
+        {
+            throw new NotSupportedException(Strings.NotSupportedReadOnlyDictionary);
+        }
+
+        bool ICollection<KeyValuePair<TKey, TValue>>.Remove(KeyValuePair<TKey, TValue> item)
+        {
+            throw new NotSupportedException(Strings.NotSupportedReadOnlyDictionary);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/ReadOnlyDictionaryDebuggerProxy.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/ReadOnlyDictionaryDebuggerProxy.cs
new file mode 100644
index 00000000000..9dda8f4bc58
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/ReadOnlyDictionaryDebuggerProxy.cs
@@ -0,0 +1,34 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using Microsoft.Internal;
+
+namespace System.Collections.ObjectModel
+{
+
+    // NOTE: This type cannot be a nested proxy of ReadOnlyDictionary due to a bug 
+    // in the Visual Studio Debugger which causes it to ignore nested generic proxies.
+    internal class ReadOnlyDictionaryDebuggerProxy<TKey, TValue>
+    {
+        private readonly ReadOnlyDictionary<TKey, TValue> _dictionary;
+        
+        public ReadOnlyDictionaryDebuggerProxy(ReadOnlyDictionary<TKey, TValue> dictionary)
+        {
+            Requires.NotNull(dictionary, "dictionary");
+            
+            _dictionary = dictionary;
+        }
+
+        [DebuggerBrowsable(DebuggerBrowsableState.RootHidden)]
+        public KeyValuePair<TKey, TValue>[] Items
+        {
+            // NOTE: This shouldn't be cached, so that on every query of
+            // the current value of the underlying dictionary is respected.
+            get { return this._dictionary.ToArray(); }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/WeakReferenceCollection.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/WeakReferenceCollection.cs
new file mode 100644
index 00000000000..fa8faddf3f3
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Collections/WeakReferenceCollection.cs
@@ -0,0 +1,85 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace Microsoft.Internal.Collections
+{
+    internal class WeakReferenceCollection<T> where T : class
+    {
+        private readonly List<WeakReference> _items = new List<WeakReference>();
+
+        public void Add(T item)
+        {
+            // Only cleanup right before we need to reallocate space.
+            if (this._items.Capacity == this._items.Count)
+            {
+                this.CleanupDeadReferences();
+            }
+
+            this._items.Add(new WeakReference(item));
+        }
+
+        public void Remove(T item)
+        {
+            int index = IndexOf(item);
+
+            if (index != -1)
+            {
+                this._items.RemoveAt(index);
+            }
+        }
+
+        public bool Contains(T item)
+        {
+            return IndexOf(item) >= 0;
+        }
+
+        public void Clear()
+        {
+            this._items.Clear();
+        }
+
+        // Should be executed under at least a read lock.
+        private int IndexOf(T item)
+        {
+            int count = this._items.Count;
+            for (int i = 0; i < count; i++)
+            {
+                if (object.ReferenceEquals(this._items[i].Target, item))
+                {
+                    return i;
+                }
+            }
+            return -1;
+        }
+
+        // Should be executed under a write lock
+        private void CleanupDeadReferences()
+        {
+            this._items.RemoveAll(w => !w.IsAlive);
+        }
+
+        public List<T> AliveItemsToList()
+        {
+            List<T> aliveItems = new List<T>();
+
+            foreach (var weakItem in this._items)
+            {
+                T item = weakItem.Target as T;
+
+                if (item != null)
+                {
+                    aliveItems.Add(item);
+                }
+            }
+
+            return aliveItems;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/ContractServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/ContractServices.cs
new file mode 100644
index 00000000000..eeccabe758f
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/ContractServices.cs
@@ -0,0 +1,42 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Hosting;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using System.ComponentModel.Composition.Primitives;
+
+namespace Microsoft.Internal
+{
+    internal static class ContractServices
+    {
+        public static bool TryCast(Type contractType, object value, out object result)
+        {
+            if (value == null)
+            {
+                result = null;
+                return true;
+            }
+            if (contractType.IsInstanceOfType(value))
+            {
+                result = value;
+                return true;
+            }
+
+            // We couldn't cast see if a delegate works for us.
+            if (typeof(Delegate).IsAssignableFrom(contractType))
+            {
+                ExportedDelegate exportedDelegate = value as ExportedDelegate;
+                if (exportedDelegate != null)
+                {
+                    result = exportedDelegate.CreateDelegate(contractType.UnderlyingSystemType);
+                    return (result != null);
+                }
+            }
+
+            result = null;
+            return false;
+        }
+    }
+}
+
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/GenerationServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/GenerationServices.cs
new file mode 100644
index 00000000000..455b7ce27fe
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/GenerationServices.cs
@@ -0,0 +1,333 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.Globalization;
+using System.Linq;
+using System.Text;
+using System.Reflection;
+using System.Reflection.Emit;
+
+namespace Microsoft.Internal
+{
+    internal static class GenerationServices
+    {
+        // Type.GetTypeFromHandle
+        private static readonly MethodInfo _typeGetTypeFromHandleMethod = typeof(Type).GetMethod("GetTypeFromHandle");
+
+
+        // typeofs are pretty expensive, so we cache them statically
+        private static readonly Type TypeType = typeof(System.Type);
+        private static readonly Type StringType = typeof(System.String);
+        private static readonly Type CharType = typeof(System.Char);
+        private static readonly Type BooleanType = typeof(System.Boolean);
+        private static readonly Type ByteType = typeof(System.Byte);
+        private static readonly Type SByteType = typeof(System.SByte);
+        private static readonly Type Int16Type = typeof(System.Int16);
+        private static readonly Type UInt16Type = typeof(System.UInt16);
+        private static readonly Type Int32Type = typeof(System.Int32);
+        private static readonly Type UInt32Type = typeof(System.UInt32);
+        private static readonly Type Int64Type = typeof(System.Int64);
+        private static readonly Type UInt64Type = typeof(System.UInt64);
+        private static readonly Type DoubleType = typeof(System.Double);
+        private static readonly Type SingleType = typeof(System.Single);
+        private static readonly Type IEnumerableTypeofT = typeof(System.Collections.Generic.IEnumerable<>);
+        private static readonly Type IEnumerableType = typeof(System.Collections.IEnumerable);
+
+        private static readonly MethodInfo ExceptionGetData = typeof(Exception).GetProperty("Data").GetGetMethod();
+        private static readonly MethodInfo DictionaryAdd = typeof(IDictionary).GetMethod("Add");
+        private static readonly ConstructorInfo ObjectCtor = typeof(object).GetConstructor(Type.EmptyTypes);
+
+        public static ILGenerator CreateGeneratorForPublicConstructor(this TypeBuilder typeBuilder, Type[] ctrArgumentTypes)
+        {
+            ConstructorBuilder ctorBuilder = typeBuilder.DefineConstructor(
+                MethodAttributes.Public,
+                CallingConventions.Standard,
+                ctrArgumentTypes);
+
+            ILGenerator ctorIL = ctorBuilder.GetILGenerator();
+            ctorIL.Emit(OpCodes.Ldarg_0);
+            ctorIL.Emit(OpCodes.Call, ObjectCtor);
+
+            return ctorIL;
+        }
+        
+        /// Generates the code that loads the supplied value on the stack
+        /// This is not as simple as it seems, as different instructions need to be generated depending
+        /// on its type.
+        /// We support:
+        /// 1. All primitive types
+        /// 2. Strings
+        /// 3. Enums
+        /// 4. typeofs
+        /// 5. nulls
+        /// 6. Enumerables
+        /// 7. Delegates on static functions or any of the above
+        /// Everything else cannot be represented as literals
+        /// <param name="ilGenerator"></param>
+        /// <param name="item"></param>
+        /// <param name="key"></param>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static void LoadValue(this ILGenerator ilGenerator, object value)
+        {
+            Assumes.NotNull(ilGenerator);
+
+            //
+            // Get nulls out of the way - they are basically typeless, so we just load null
+            //
+            if (value == null)
+            {
+                ilGenerator.LoadNull();
+                return;
+            }
+
+            //
+            // Prepare for literal loading - decide whether we should box, and handle enums properly
+            //
+            Type valueType = value.GetType();
+            object rawValue = value;
+            if (valueType.IsEnum)
+            {
+                // enums are special - we need to load the underlying constant on the stack
+                rawValue = Convert.ChangeType(value, Enum.GetUnderlyingType(valueType), null);
+                valueType = rawValue.GetType();
+            }
+
+            //
+            // Generate IL depending on the valueType - this is messier than it should ever be, but sadly necessary
+            //
+            if (valueType == GenerationServices.StringType)
+            {
+                // we need to check for strings before enumerables, because strings are IEnumerable<char>
+                ilGenerator.LoadString((string)rawValue);
+            }
+            else if (GenerationServices.TypeType.IsAssignableFrom(valueType))
+            {
+                ilGenerator.LoadTypeOf((Type)rawValue);
+            }
+            else if (GenerationServices.IEnumerableType.IsAssignableFrom(valueType))
+            {
+                // NOTE : strings and dictionaries are also enumerables, but we have already handled those
+                ilGenerator.LoadEnumerable((IEnumerable) rawValue);
+            }
+            else if (
+                (valueType == GenerationServices.CharType) ||
+                (valueType == GenerationServices.BooleanType) ||
+                (valueType == GenerationServices.ByteType) ||
+                (valueType == GenerationServices.SByteType) ||
+                (valueType == GenerationServices.Int16Type) ||
+                (valueType == GenerationServices.UInt16Type) ||
+                (valueType == GenerationServices.Int32Type)
+                )
+            {
+                // NOTE : Everything that is 32 bit or less uses ldc.i4. We need to pass int32, even if the actual types is shorter - this is IL memory model
+                // direct casting to (int) won't work, because the value is boxed, thus we need to use Convert.
+                // Sadly, this will not work for all cases - namely large uint32 - because they can't semantically fit into 32 signed bits
+                // We have a special case for that next
+                ilGenerator.LoadInt((int)Convert.ChangeType(rawValue, typeof(int), CultureInfo.InvariantCulture));
+            }
+            else if (valueType == GenerationServices.UInt32Type)
+            {
+                // NOTE : This one is a bit tricky. Ldc.I4 takes an Int32 as an argument, although it really treats it as a 32bit number
+                // That said, some UInt32 values are larger that Int32.MaxValue, so the Convert call above will fail, which is why 
+                // we need to treat this case individually and cast to uint, and then - unchecked - to int.
+                ilGenerator.LoadInt(unchecked((int)((uint)rawValue)));
+            }
+            else if (valueType == GenerationServices.Int64Type)
+            {
+                ilGenerator.LoadLong((long)rawValue);
+            }
+            else if (valueType == GenerationServices.UInt64Type)
+            {
+                // NOTE : This one is a bit tricky. Ldc.I8 takes an Int64 as an argument, although it really treats it as a 64bit number
+                // That said, some UInt64 values are larger that Int64.MaxValue, so the direct case we use above (or Convert, for that matter)will fail, which is why
+                // we need to treat this case individually and cast to ulong, and then - unchecked - to long.
+                ilGenerator.LoadLong(unchecked((long)((ulong)rawValue)));
+            }
+            else if (valueType == GenerationServices.SingleType)
+            {
+                ilGenerator.LoadFloat((float)rawValue);
+            }
+            else if (valueType == GenerationServices.DoubleType)
+            {
+                ilGenerator.LoadDouble((double)rawValue);
+            }
+            else
+            {
+                throw new InvalidOperationException(
+                    string.Format(CultureInfo.CurrentCulture, Strings.InvalidMetadataValue, value.GetType().FullName));
+            }
+        }
+
+        /// Generates the code that adds an object to a dictionary stored in a local variable
+        /// <param name="ilGenerator"></param>
+        /// <param name="dictionary"></param>
+        /// <param name="key"></param>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static void AddItemToLocalDictionary(this ILGenerator ilGenerator, LocalBuilder dictionary, object key, object value)
+        {
+            Assumes.NotNull(ilGenerator);
+            Assumes.NotNull(dictionary);
+            Assumes.NotNull(key);
+            Assumes.NotNull(value);
+
+            ilGenerator.Emit(OpCodes.Ldloc, dictionary);
+            ilGenerator.LoadValue(key);
+            ilGenerator.LoadValue(value);
+            ilGenerator.Emit(OpCodes.Callvirt, DictionaryAdd);
+        }
+
+        /// Generates the code that adds an object from a local variable to a dictionary also stored in a local
+        /// <param name="ilGenerator"></param>
+        /// <param name="dictionary"></param>
+        /// <param name="key"></param>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static void AddLocalToLocalDictionary(this ILGenerator ilGenerator, LocalBuilder dictionary, object key, LocalBuilder value)
+        {
+            Assumes.NotNull(ilGenerator);
+            Assumes.NotNull(dictionary);
+            Assumes.NotNull(key);
+            Assumes.NotNull(value);
+
+            ilGenerator.Emit(OpCodes.Ldloc, dictionary);
+            ilGenerator.LoadValue(key);
+            ilGenerator.Emit(OpCodes.Ldloc, value);
+            ilGenerator.Emit(OpCodes.Callvirt, DictionaryAdd);
+        }
+
+        /// Generates the code to get the type of an object and store it in a local
+        /// <param name="ilGenerator"></param>
+        /// <param name="dictionary"></param>
+        /// <param name="key"></param>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static void GetExceptionDataAndStoreInLocal(this ILGenerator ilGenerator, LocalBuilder exception, LocalBuilder dataStore)
+        {
+            Assumes.NotNull(ilGenerator);
+            Assumes.NotNull(exception);
+            Assumes.NotNull(dataStore);
+
+            ilGenerator.Emit(OpCodes.Ldloc, exception);
+            ilGenerator.Emit(OpCodes.Callvirt, ExceptionGetData);
+            ilGenerator.Emit(OpCodes.Stloc, dataStore);
+        }
+
+        private static void LoadEnumerable(this ILGenerator ilGenerator, IEnumerable enumerable)
+        {
+            Assumes.NotNull(ilGenerator);
+            Assumes.NotNull(enumerable);
+
+            // We load enumerable as an array - this is the most compact and efficient way of representing it
+            Type elementType = null;
+            Type closedType = null;
+            if (ReflectionServices.TryGetGenericInterfaceType(enumerable.GetType(), GenerationServices.IEnumerableTypeofT, out closedType))
+            {
+                elementType = closedType.GetGenericArguments()[0];
+            }
+            else
+            {
+                elementType = typeof(object);
+            }
+
+            //
+            // elem[] array = new elem[<enumerable.Count()>]
+            //
+            Type generatedArrayType = elementType.MakeArrayType();
+            LocalBuilder generatedArrayLocal = ilGenerator.DeclareLocal(generatedArrayType);
+
+            ilGenerator.LoadInt(enumerable.Cast<object>().Count());
+            ilGenerator.Emit(OpCodes.Newarr, elementType);
+            ilGenerator.Emit(OpCodes.Stloc, generatedArrayLocal);
+            
+            int index = 0;
+            foreach (object value in enumerable)
+            {
+                //
+                //array[<index>] = value;
+                //
+                ilGenerator.Emit(OpCodes.Ldloc, generatedArrayLocal);
+                ilGenerator.LoadInt(index);
+                ilGenerator.LoadValue(value);
+                if (GenerationServices.IsBoxingRequiredForValue(value) && !elementType.IsValueType)
+                {
+                    ilGenerator.Emit(OpCodes.Box, value.GetType());
+                }
+                ilGenerator.Emit(OpCodes.Stelem, elementType);
+                index++;
+            }
+
+            ilGenerator.Emit(OpCodes.Ldloc, generatedArrayLocal);
+        }
+
+        private static bool IsBoxingRequiredForValue(object value)
+        {
+            if (value == null)
+            {
+                return false;
+            }
+            else
+            {
+                return value.GetType().IsValueType;
+            }
+        }
+
+
+        private static void LoadNull(this ILGenerator ilGenerator)
+        {
+            ilGenerator.Emit(OpCodes.Ldnull);
+        }
+
+        private static void LoadString(this ILGenerator ilGenerator, string s)
+        {
+            Assumes.NotNull(ilGenerator);
+            if (s == null)
+            {
+                ilGenerator.LoadNull();
+            }
+            else
+            {
+                ilGenerator.Emit(OpCodes.Ldstr, s);
+            }
+        }
+
+
+        private static void LoadInt(this ILGenerator ilGenerator, int value)
+        {
+            Assumes.NotNull(ilGenerator);
+            ilGenerator.Emit(OpCodes.Ldc_I4, value);
+        }
+
+        private static void LoadLong(this ILGenerator ilGenerator, long value)
+        {
+            Assumes.NotNull(ilGenerator);
+            ilGenerator.Emit(OpCodes.Ldc_I8, value);
+        }
+
+        private static void LoadFloat(this ILGenerator ilGenerator, float value)
+        {
+            Assumes.NotNull(ilGenerator);
+            ilGenerator.Emit(OpCodes.Ldc_R4, value);
+        }
+
+        private static void LoadDouble(this ILGenerator ilGenerator, double value)
+        {
+            Assumes.NotNull(ilGenerator);
+            ilGenerator.Emit(OpCodes.Ldc_R8, value);
+        }
+
+        private static void LoadTypeOf(this ILGenerator ilGenerator, Type type)
+        {
+            Assumes.NotNull(ilGenerator);
+            //typeofs() translate into ldtoken and Type::GetTypeFromHandle call
+            ilGenerator.Emit(OpCodes.Ldtoken, type);
+            ilGenerator.EmitCall(OpCodes.Call, GenerationServices._typeGetTypeFromHandleMethod, null);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/LazyServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/LazyServices.cs
new file mode 100644
index 00000000000..ba3f2592561
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/LazyServices.cs
@@ -0,0 +1,26 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Globalization;
+using System.Threading;
+
+namespace Microsoft.Internal
+{
+    internal static class LazyServices
+    {
+        public static T GetNotNullValue<T>(this Lazy<T> lazy, string argument)
+            where T : class
+        {
+            Assumes.NotNull(lazy);
+            T value = lazy.Value;
+            if (value == null)
+            {
+                throw new InvalidOperationException(
+                    string.Format(CultureInfo.CurrentCulture, Strings.LazyServices_LazyResolvesToNull, typeof(T), argument));
+            }
+
+            return value;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Lock.Reader.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Lock.Reader.cs
new file mode 100644
index 00000000000..1f620349a2e
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Lock.Reader.cs
@@ -0,0 +1,32 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading;
+
+namespace Microsoft.Internal
+{
+    internal struct ReadLock : IDisposable
+    {
+        private readonly Lock _lock;
+        private int _isDisposed;
+
+        public ReadLock(Lock @lock)
+        {
+            this._isDisposed = 0;
+            this._lock = @lock;
+            this._lock.EnterReadLock();
+        }
+
+        public void Dispose()
+        {
+            if (Interlocked.CompareExchange(ref this._isDisposed, 1, 0) == 0)
+            {
+                this._lock.ExitReadLock();
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Lock.Writer.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Lock.Writer.cs
new file mode 100644
index 00000000000..1e8aef0bd44
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Lock.Writer.cs
@@ -0,0 +1,32 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading;
+
+namespace Microsoft.Internal
+{
+    internal struct WriteLock : IDisposable
+    {
+        private readonly Lock _lock;
+        private int _isDisposed;
+
+        public WriteLock(Lock @lock)
+        {
+            this._isDisposed = 0;
+            this._lock = @lock;
+            this._lock.EnterWriteLock();
+        }
+
+        public void Dispose()
+        {
+            if (Interlocked.CompareExchange(ref this._isDisposed, 1, 0) == 0)
+            {
+                this._lock.ExitWriteLock();
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Lock.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Lock.cs
new file mode 100644
index 00000000000..82810ac6121
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Lock.cs
@@ -0,0 +1,79 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading;
+
+namespace Microsoft.Internal
+{
+    internal sealed class Lock : IDisposable
+    {
+#if (FEATURE_SLIMLOCK)
+        private ReaderWriterLockSlim _thisLock = new ReaderWriterLockSlim(LockRecursionPolicy.NoRecursion);
+        private int _isDisposed = 0;
+        public void EnterReadLock()
+        {
+            this._thisLock.EnterReadLock();
+        }
+
+        public void EnterWriteLock()
+        {
+            this._thisLock.EnterWriteLock();
+        }
+
+        public void ExitReadLock()
+        {
+            this._thisLock.ExitReadLock();
+        }
+
+        public void ExitWriteLock()
+        {
+            this._thisLock.ExitWriteLock();
+        }
+
+        public void Dispose()
+        {
+            if (Interlocked.CompareExchange(ref this._isDisposed, 1, 0) == 0)
+            {
+                this._thisLock.Dispose();
+            }
+        }
+
+#else
+        // ReaderWriterLockSlim is not yet implemented on SilverLight
+        // Satisfies our requirements until it is implemented
+        object _thisLock = new object();
+
+        public Lock()
+        {
+        }
+
+        public void EnterReadLock()
+        {
+            Monitor.Enter(this._thisLock);
+        }
+
+        public void EnterWriteLock()
+        {
+            Monitor.Enter(this._thisLock);
+        }
+
+        public void ExitReadLock()
+        {
+            Monitor.Exit(this._thisLock);
+        }
+
+        public void ExitWriteLock()
+        {
+            Monitor.Exit(this._thisLock);
+        }
+
+        public void Dispose()
+        {
+        }
+#endif
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/ReflectionInvoke.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/ReflectionInvoke.cs
new file mode 100644
index 00000000000..51d5dc9d9db
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/ReflectionInvoke.cs
@@ -0,0 +1,119 @@
+using System;
+using System.Reflection;
+using System.Security;
+using System.Security.Permissions;
+
+namespace Microsoft.Internal
+{
+    internal static class ReflectionInvoke
+    {
+        public static object SafeCreateInstance(this Type type, params object[] arguments)
+        {
+            DemandMemberAccessIfNeeded(type);
+
+            return Activator.CreateInstance(type, arguments);
+        }
+
+        public static object SafeInvoke(this ConstructorInfo constructor, params object[] arguments)
+        {
+            DemandMemberAccessIfNeeded(constructor);
+
+            return constructor.Invoke(arguments);
+        }
+
+        public static object SafeInvoke(this MethodInfo method, object instance, params object[] arguments)
+        {
+            DemandMemberAccessIfNeeded(method);
+
+            return method.Invoke(instance, arguments);
+        }
+
+        public static object SafeGetValue(this FieldInfo field, object instance)
+        {
+            DemandMemberAccessIfNeeded(field);
+
+            return field.GetValue(instance);
+        }
+
+        public static void SafeSetValue(this FieldInfo field, object instance, object value)
+        {
+            DemandMemberAccessIfNeeded(field);
+
+            field.SetValue(instance, value);
+        }
+
+#if FEATURE_CAS_APTCA
+        private static readonly ReflectionPermission _memberAccess = new ReflectionPermission(ReflectionPermissionFlag.MemberAccess);
+        private static readonly ReflectionPermission _restrictedMemberAccess = new ReflectionPermission(ReflectionPermissionFlag.RestrictedMemberAccess);
+        
+        public static void DemandMemberAccessIfNeeded(MethodInfo method)
+        {
+            if (!method.IsVisible())
+            {
+                DemandMemberAccess(method);
+            }
+        }
+
+        private static void DemandMemberAccessIfNeeded(FieldInfo field)
+        {
+            if (!field.IsVisible())
+            {
+                DemandMemberAccess(field);
+            }
+        }
+
+        public static void DemandMemberAccessIfNeeded(Type type)
+        {
+            // Consult UnderlyingSystemType this is the type that Activator.CreateInstance creates            
+            if (!type.UnderlyingSystemType.IsVisible)
+            {
+                DemandMemberAccess(type);
+            }
+        }
+
+        private static void DemandMemberAccessIfNeeded(ConstructorInfo constructor)
+        {
+            if (!constructor.IsVisible())
+            {
+                DemandMemberAccess(constructor);
+            }
+        }
+
+        [System.Security.SecuritySafeCritical]
+        private static void DemandMemberAccess(MemberInfo target)
+        {
+            try
+            {
+                _memberAccess.Demand();
+            }
+            catch (SecurityException)
+            {   // The caller doesn't have member access, but let's see whether they have access to
+                // members of assemblies with less or equal permissions (this mimics Reflection's behavior)
+
+                DemandRestrictedMemberAccess(target);
+            }
+        }
+
+        [System.Security.SecuritySafeCritical]
+        private static void DemandRestrictedMemberAccess(MemberInfo target)
+        {
+            Assembly targetAssembly = target.Assembly();
+
+            PermissionSet targetGrantSet = UnsafePermissionSet(targetAssembly);
+            targetGrantSet.AddPermission(_restrictedMemberAccess);
+            targetGrantSet.Demand();
+        }
+
+        [SecuritySafeCritical] // PermissionSet is [SecurityCritical]
+        private static PermissionSet UnsafePermissionSet(Assembly assembly)
+        {
+            return assembly.PermissionSet;
+        }
+#else
+        public static void DemandMemberAccessIfNeeded(MethodInfo method) { }
+        private static void DemandMemberAccessIfNeeded(ConstructorInfo constructor) { }
+        private static void DemandMemberAccessIfNeeded(FieldInfo field) { }
+        public static void DemandMemberAccessIfNeeded(Type type) { }
+#endif //FEATURE_CAS_APTCA
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/ReflectionServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/ReflectionServices.cs
new file mode 100644
index 00000000000..3c0860ec880
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/ReflectionServices.cs
@@ -0,0 +1,171 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using System.Reflection;
+using System.Runtime.InteropServices;
+using System.ComponentModel.Composition;
+
+namespace Microsoft.Internal
+{
+    internal static class ReflectionServices
+    {
+        public static Assembly Assembly(this MemberInfo member)
+        {
+            Type type = member as Type;
+            if (type != null)
+            {
+                return type.Assembly;
+            }
+
+            return member.DeclaringType.Assembly;
+        }
+
+        public static bool IsVisible(this ConstructorInfo constructor)
+        {
+            return constructor.DeclaringType.IsVisible && constructor.IsPublic;
+        }
+
+        public static bool IsVisible(this FieldInfo field)
+        {
+            return field.DeclaringType.IsVisible && field.IsPublic;
+        }
+
+        public static bool IsVisible(this MethodInfo method)
+        {
+            if (!method.DeclaringType.IsVisible)
+                return false;
+
+            if (!method.IsPublic)
+                return false;
+
+            if (method.IsGenericMethod)
+            {
+                // Check type arguments, for example if we're passed 'Activator.CreateInstance<SomeMefInternalType>()'
+                foreach (Type typeArgument in method.GetGenericArguments())
+                {
+                    if (!typeArgument.IsVisible)
+                        return false;
+                }
+            }
+
+            return true;
+        }
+
+        public static string GetDisplayName(Type declaringType, string name)
+        {
+            Assumes.NotNull(declaringType);
+
+            return declaringType.GetDisplayName() + "." + name;
+        }
+
+        public static string GetDisplayName(this MemberInfo member)
+        {
+            Assumes.NotNull(member);
+  
+            switch (member.MemberType)
+            {
+                case MemberTypes.TypeInfo:
+                case MemberTypes.NestedType:
+
+                    return AttributedModelServices.GetTypeIdentity(((Type)member));
+            }
+
+            return GetDisplayName(member.DeclaringType, member.Name);            
+        }
+
+        internal static bool TryGetGenericInterfaceType(Type instanceType, Type targetOpenInterfaceType, out Type targetClosedInterfaceType)
+        {
+            // The interface must be open
+            Assumes.IsTrue(targetOpenInterfaceType.IsInterface);
+            Assumes.IsTrue(targetOpenInterfaceType.IsGenericTypeDefinition);
+            Assumes.IsTrue(!instanceType.IsGenericTypeDefinition);
+
+            // if instanceType is an interface, we must first check it directly
+            if (instanceType.IsInterface &&
+                instanceType.IsGenericType &&
+                instanceType.UnderlyingSystemType.GetGenericTypeDefinition() == targetOpenInterfaceType.UnderlyingSystemType)
+            {
+                targetClosedInterfaceType = instanceType;
+                return true;
+            }
+
+            try
+            {
+                // Purposefully not using FullName here because it results in a significantly
+                //  more expensive implementation of GetInterface, this does mean that we're
+                //  takign the chance that there aren't too many types which implement multiple
+                //  interfaces by the same name...
+                Type targetInterface = instanceType.GetInterface(targetOpenInterfaceType.Name, false);
+                if (targetInterface != null &&
+                    targetInterface.UnderlyingSystemType.GetGenericTypeDefinition() == targetOpenInterfaceType.UnderlyingSystemType)
+                {
+                    targetClosedInterfaceType = targetInterface;
+                    return true;
+                }
+            }
+            catch (AmbiguousMatchException)
+            {
+                // If there are multiple with the same name we should not pick any
+            }
+
+            targetClosedInterfaceType = null;
+            return false;
+        }
+
+        internal static IEnumerable<PropertyInfo> GetAllProperties(this Type type)
+        {
+            return type.GetInterfaces().Concat(new Type[] { type }).SelectMany(itf => itf.GetProperties());
+        }
+
+        internal static IEnumerable<MethodInfo> GetAllMethods(this Type type)
+        {
+            IEnumerable<MethodInfo> declaredMethods = type.GetDeclaredMethods();
+
+            Type baseType = type.BaseType;
+            if (baseType.UnderlyingSystemType != typeof(object))
+            {
+                return declaredMethods.Concat(baseType.GetAllMethods());
+            }
+            else
+            {
+                return declaredMethods;
+            }
+        }
+
+        private static IEnumerable<MethodInfo> GetDeclaredMethods(this Type type)
+        {
+            foreach (MethodInfo method in type.GetMethods(BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.DeclaredOnly))
+            {
+                yield return method;
+            }
+        }
+
+
+        public static IEnumerable<FieldInfo> GetAllFields(this Type type)
+        {
+            IEnumerable<FieldInfo> declaredFields = type.GetDeclaredFields();
+
+            Type baseType = type.BaseType;
+            if (baseType.UnderlyingSystemType != typeof(object))
+            {
+                return declaredFields.Concat(baseType.GetAllFields());
+            }
+            else
+            {
+                return declaredFields;
+            }
+        }
+
+        private static IEnumerable<FieldInfo> GetDeclaredFields(this Type type)
+        {
+            foreach (FieldInfo m in type.GetFields(BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.DeclaredOnly))
+            {
+                yield return m;
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Requires.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Requires.cs
new file mode 100644
index 00000000000..245f4df7729
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Requires.cs
@@ -0,0 +1,105 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.Diagnostics;
+using System.Diagnostics.Contracts;
+using System.Globalization;
+using System.Reflection;
+
+namespace Microsoft.Internal
+{
+    internal static class Requires
+    {
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        public static void NotNull<T>(T value, string parameterName) 
+            where T : class
+        {
+            if (value == null)
+            {
+                throw new ArgumentNullException(parameterName);
+            }
+            Contract.EndContractBlock();
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        public static void NotNullOrEmpty(string value, string parameterName)
+        {
+            NotNull(value, parameterName);
+
+            if (value.Length == 0)
+            {
+                throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, Strings.ArgumentException_EmptyString, parameterName), parameterName);
+            }
+            Contract.EndContractBlock();
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        public static void NotNullOrNullElements<T>(IEnumerable<T> values, string parameterName)
+            where T : class
+        {
+            NotNull(values, parameterName);
+            NotNullElements(values, parameterName);
+            Contract.EndContractBlock();
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        public static void NullOrNotNullElements<TKey, TValue>(IEnumerable<KeyValuePair<TKey, TValue>> values, string parameterName)
+            where TKey : class
+            where TValue : class
+        {
+            NotNullElements(values, parameterName);
+            Contract.EndContractBlock();
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        public static void NullOrNotNullElements<T>(IEnumerable<T> values, string parameterName)
+            where T : class
+        {
+            NotNullElements(values, parameterName);
+            Contract.EndContractBlock();
+        }
+
+        [ContractArgumentValidator]
+        private static void NotNullElements<T>(IEnumerable<T> values, string parameterName)
+            where T : class
+        {
+            if (values != null && !Contract.ForAll(values, (value) => value != null))
+            {
+                throw ExceptionBuilder.CreateContainsNullElement(parameterName);
+            }
+            Contract.EndContractBlock();
+        }
+
+        [ContractArgumentValidator]
+        private static void NotNullElements<TKey, TValue>(IEnumerable<KeyValuePair<TKey, TValue>> values, string parameterName)
+            where TKey : class
+            where TValue : class
+        {
+            if (values != null && !Contract.ForAll(values, (keyValue) => keyValue.Key != null && keyValue.Value != null))
+            {
+                throw ExceptionBuilder.CreateContainsNullElement(parameterName);
+            }
+            Contract.EndContractBlock();
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        public static void IsInMembertypeSet(MemberTypes value, string parameterName, MemberTypes enumFlagSet)
+        {
+            if ((value & enumFlagSet) != value || // Ensure the member is in the set
+                (value & (value - 1)) != 0) // Ensure that there is only one flag in the value (i.e. value is a power of 2).
+            {
+                throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, Strings.ArgumentOutOfRange_InvalidEnumInSet, parameterName, value, enumFlagSet.ToString()), parameterName);
+            }
+            Contract.EndContractBlock();
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Runtime/Serialization/SerializationServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Runtime/Serialization/SerializationServices.cs
new file mode 100644
index 00000000000..74d1ca783cf
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/Runtime/Serialization/SerializationServices.cs
@@ -0,0 +1,20 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Runtime.Serialization;
+
+namespace Microsoft.Internal.Runtime.Serialization
+{
+#if FEATURE_SERIALIZATION
+    internal static class SerializationServices
+    {
+        public static T GetValue<T>(this SerializationInfo info, string name)
+        {
+            Assumes.NotNull(info, name);
+
+            return (T)info.GetValue(name, typeof(T));
+        }
+    }
+#endif //FEATURE_SERIALIZATION
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/StringComparers.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/StringComparers.cs
new file mode 100644
index 00000000000..5cb9747bedb
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Microsoft/Internal/StringComparers.cs
@@ -0,0 +1,20 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+
+namespace Microsoft.Internal
+{
+    internal static class StringComparers
+    {
+        public static StringComparer ContractName
+        {
+            get { return StringComparer.Ordinal; }
+        }
+        
+        public static StringComparer MetadataKeyNames
+        {
+            get { return StringComparer.Ordinal; }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/PlatformWorkarounds.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/PlatformWorkarounds.cs
new file mode 100644
index 00000000000..4f6800aba5d
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/PlatformWorkarounds.cs
@@ -0,0 +1,45 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+
+#if !FEATURE_SERIALIZATION
+namespace System
+{
+    [Conditional("NOT_FEATURE_SERIALIZATION")]    // Trick so that the attribute is never actually applied
+    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Enum | AttributeTargets.Delegate, Inherited = false)]
+    internal sealed class SerializableAttribute : Attribute
+    {
+    }
+}
+#endif //!FEATURE_SERIALIZATION
+
+#if !FEATURE_LEGACYCOMPONENTMODEL
+namespace System.ComponentModel
+{
+    [Conditional("NOT_FEATURE_LEGACYCOMPONENTMODEL")]    // Trick so that the attribute is never actually applied
+    internal sealed class LocalizableAttribute : Attribute
+    {
+        [SuppressMessage("Microsoft.Usage", "CA1801:ReviewUnusedParameters", MessageId = "isLocalizable")]
+        public LocalizableAttribute(bool isLocalizable)
+        {
+        }
+    }
+}
+#endif //!FEATURE_LEGACYCOMPONENTMODEL
+
+// This is temporary as contracts should actually be everywhere. Once CORE_CLR adds back this attribute, this will be gone
+#if FEATURE_MISSINGCONTRACTARGUMENTVALIDATOR
+namespace System.Diagnostics.Contracts
+{
+    [Conditional("NOT_FEATURE_MISSINGCONTRACTARGUMENTVALIDATOR")]    // Trick so that the attribute is never actually applied
+    [AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]
+    internal sealed class ContractArgumentValidatorAttribute : Attribute
+    {
+    }
+}
+#endif //FEATURE_MISSINGCONTRACTARGUMENTVALIDATOR
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Strings.Designer.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Strings.Designer.cs
new file mode 100644
index 00000000000..39feed44897
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Strings.Designer.cs
@@ -0,0 +1,1044 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by a tool.
+//     Runtime Version:4.0.30319.16815
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+namespace Microsoft.Internal {
+    using System;
+    
+    
+    /// <summary>
+    ///   A strongly-typed resource class, for looking up localized strings, etc.
+    /// </summary>
+    // This class was auto-generated by the StronglyTypedResourceBuilder
+    // class via a tool like ResGen or Visual Studio.
+    // To add or remove a member, edit your .ResX file then rerun ResGen
+    // with the /str option, or rebuild your VS project.
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "4.0.0.0")]
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+    [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
+    internal class Strings {
+        
+        private static global::System.Resources.ResourceManager resourceMan;
+        
+        private static global::System.Globalization.CultureInfo resourceCulture;
+        
+        [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
+        internal Strings() {
+        }
+        
+        /// <summary>
+        ///   Returns the cached ResourceManager instance used by this class.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Resources.ResourceManager ResourceManager {
+            get {
+                if (object.ReferenceEquals(resourceMan, null)) {
+                    global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("Microsoft.Internal.Strings", typeof(Strings).Assembly);
+                    resourceMan = temp;
+                }
+                return resourceMan;
+            }
+        }
+        
+        /// <summary>
+        ///   Overrides the current thread's CurrentUICulture property for all
+        ///   resource lookups using this strongly typed resource class.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Globalization.CultureInfo Culture {
+            get {
+                return resourceCulture;
+            }
+            set {
+                resourceCulture = value;
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;{0}&apos; is a reflection-only assembly which is not supported..
+        /// </summary>
+        internal static string Argument_AssemblyReflectionOnly {
+            get {
+                return ResourceManager.GetString("Argument_AssemblyReflectionOnly", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;{0}&apos; contains a reflection-only type which is not supported..
+        /// </summary>
+        internal static string Argument_ElementReflectionOnlyType {
+            get {
+                return ResourceManager.GetString("Argument_ElementReflectionOnlyType", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;exports&apos; cannot be empty when ImportDefinition.ImportCardinality is ImportCardinality.ExactlyOne..
+        /// </summary>
+        internal static string Argument_ExportsEmpty {
+            get {
+                return ResourceManager.GetString("Argument_ExportsEmpty", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;exports&apos; cannot contain more than one element when ImportDefinition.ImportCardinality is ImportCardinality.ZeroOrOne or ImportCardinality.ExactlyOne..
+        /// </summary>
+        internal static string Argument_ExportsTooMany {
+            get {
+                return ResourceManager.GetString("Argument_ExportsTooMany", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;{0}&apos; cannot contain a null (Nothing in Visual Basic) element..
+        /// </summary>
+        internal static string Argument_NullElement {
+            get {
+                return ResourceManager.GetString("Argument_NullElement", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;{0}&apos; returns a mapped type that is a reflection-only type which is not supported..
+        /// </summary>
+        internal static string Argument_ReflectionContextReturnsReflectionOnlyType {
+            get {
+                return ResourceManager.GetString("Argument_ReflectionContextReturnsReflectionOnlyType", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;{0}&apos; cannot be an empty string (&quot;&quot;)..
+        /// </summary>
+        internal static string ArgumentException_EmptyString {
+            get {
+                return ResourceManager.GetString("ArgumentException_EmptyString", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The value of argument &apos;{0}&apos; ({1}) is invalid for Enum type &apos;{2}&apos;..
+        /// </summary>
+        internal static string ArgumentOutOfRange_InvalidEnum {
+            get {
+                return ResourceManager.GetString("ArgumentOutOfRange_InvalidEnum", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The value of argument &apos;{0}&apos; ({1}) is not supported. Allowed values are : &apos;{2}&apos;..
+        /// </summary>
+        internal static string ArgumentOutOfRange_InvalidEnumInSet {
+            get {
+                return ResourceManager.GetString("ArgumentOutOfRange_InvalidEnumInSet", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The argument was a value type which is not supported..
+        /// </summary>
+        internal static string ArgumentValueType {
+            get {
+                return ResourceManager.GetString("ArgumentValueType", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Assembly file {0} is either not found or not a dll or exe file..
+        /// </summary>
+        internal static string AssemblyFileNotFoundOrWrongType {
+            get {
+                return ResourceManager.GetString("AssemblyFileNotFoundOrWrongType", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The atomicComposition can no longer be changed because the atomicComposition has already been completed..
+        /// </summary>
+        internal static string AtomicComposition_AlreadyCompleted {
+            get {
+                return ResourceManager.GetString("AtomicComposition_AlreadyCompleted", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The atomicComposition already contains an inner atomicComposition and cannot contain more than one atomicComposition at a time..
+        /// </summary>
+        internal static string AtomicComposition_AlreadyNested {
+            get {
+                return ResourceManager.GetString("AtomicComposition_AlreadyNested", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The atomicComposition contains another inner atomicComposition and cannot be changed until the that inner atomicComposition has been completed..
+        /// </summary>
+        internal static string AtomicComposition_PartOfAnotherAtomicComposition {
+            get {
+                return ResourceManager.GetString("AtomicComposition_PartOfAnotherAtomicComposition", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to No exports were found that match the constraint: {0}.
+        /// </summary>
+        internal static string CardinalityMismatch_NoExports {
+            get {
+                return ResourceManager.GetString("CardinalityMismatch_NoExports", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to More than one export was found that matches the constraint: {0}.
+        /// </summary>
+        internal static string CardinalityMismatch_TooManyExports {
+            get {
+                return ResourceManager.GetString("CardinalityMismatch_TooManyExports", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to ScopingPolicyCatalog does not support catalog mutation..
+        /// </summary>
+        internal static string CatalogMutation_Invalid {
+            get {
+                return ResourceManager.GetString("CatalogMutation_Invalid", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Unknown Origin.
+        /// </summary>
+        internal static string CompositionElement_UnknownOrigin {
+            get {
+                return ResourceManager.GetString("CompositionElement_UnknownOrigin", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The composition remains unchanged. The changes were rejected because of the following error(s): {0}.
+        /// </summary>
+        internal static string CompositionException_ChangesRejected {
+            get {
+                return ResourceManager.GetString("CompositionException_ChangesRejected", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Element: {0}.
+        /// </summary>
+        internal static string CompositionException_ElementPrefix {
+            get {
+                return ResourceManager.GetString("CompositionException_ElementPrefix", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Resulting in:.
+        /// </summary>
+        internal static string CompositionException_ErrorPrefix {
+            get {
+                return ResourceManager.GetString("CompositionException_ErrorPrefix", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Unable to create an instance of the Metadata view &apos;{0}&apos; because a constructor could not be selected.  Ensure that the type implements a constructor which takes an argument of type IDictionary&lt;string, object&gt;..
+        /// </summary>
+        internal static string CompositionException_MetadataViewInvalidConstructor {
+            get {
+                return ResourceManager.GetString("CompositionException_MetadataViewInvalidConstructor", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The composition produced multiple composition errors, with {0:N0} root causes. The root causes are provided below..
+        /// </summary>
+        internal static string CompositionException_MultipleErrorsWithMultiplePaths {
+            get {
+                return ResourceManager.GetString("CompositionException_MultipleErrorsWithMultiplePaths", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to  {0} {1}.
+        /// </summary>
+        internal static string CompositionException_OriginFormat {
+            get {
+                return ResourceManager.GetString("CompositionException_OriginFormat", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to --&gt; .
+        /// </summary>
+        internal static string CompositionException_OriginSeparator {
+            get {
+                return ResourceManager.GetString("CompositionException_OriginSeparator", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to ).
+        /// </summary>
+        internal static string CompositionException_PathsCountSeparator {
+            get {
+                return ResourceManager.GetString("CompositionException_PathsCountSeparator", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Review the CompositionException.Errors property for more detailed information..
+        /// </summary>
+        internal static string CompositionException_ReviewErrorProperty {
+            get {
+                return ResourceManager.GetString("CompositionException_ReviewErrorProperty", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The composition produced a single composition error, with {0:N0} root causes. The root causes are provided below..
+        /// </summary>
+        internal static string CompositionException_SingleErrorWithMultiplePaths {
+            get {
+                return ResourceManager.GetString("CompositionException_SingleErrorWithMultiplePaths", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The composition produced a single composition error. The root cause is provided below..
+        /// </summary>
+        internal static string CompositionException_SingleErrorWithSinglePath {
+            get {
+                return ResourceManager.GetString("CompositionException_SingleErrorWithSinglePath", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The catalog &apos;{0}&apos; could not load assembly &apos;{1}&apos;. {2}.
+        /// </summary>
+        internal static string CompositionTrace_Discovery_AssemblyLoadFailed {
+            get {
+                return ResourceManager.GetString("CompositionTrace_Discovery_AssemblyLoadFailed", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The ComposablePartDefinition &apos;{0}&apos; was ignored because it contains no exports..
+        /// </summary>
+        internal static string CompositionTrace_Discovery_DefinitionContainsNoExports {
+            get {
+                return ResourceManager.GetString("CompositionTrace_Discovery_DefinitionContainsNoExports", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The ComposablePartDefinition &apos;{0}&apos; was ignored because it was marked with PartNotDiscoverableAttribute..
+        /// </summary>
+        internal static string CompositionTrace_Discovery_DefinitionMarkedWithPartNotDiscoverableAttribute {
+            get {
+                return ResourceManager.GetString("CompositionTrace_Discovery_DefinitionMarkedWithPartNotDiscoverableAttribute", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The composable part definition &apos;{0}&apos; was ignored because the export &apos;{1}&apos; has different generic parameters than the part type..
+        /// </summary>
+        internal static string CompositionTrace_Discovery_DefinitionMismatchedExportArity {
+            get {
+                return ResourceManager.GetString("CompositionTrace_Discovery_DefinitionMismatchedExportArity", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The member or parameter &apos;{0}&apos; is marked with multiple Import and ImportMany attributes. Only the first attribute encountered will be respected..
+        /// </summary>
+        internal static string CompositionTrace_Discovery_MemberMarkedWithMultipleImportAndImportMany {
+            get {
+                return ResourceManager.GetString("CompositionTrace_Discovery_MemberMarkedWithMultipleImportAndImportMany", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The ComposablePartDefinition &apos;{0}&apos; has been rejected. {1}.
+        /// </summary>
+        internal static string CompositionTrace_Rejection_DefinitionRejected {
+            get {
+                return ResourceManager.GetString("CompositionTrace_Rejection_DefinitionRejected", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The ComposablePartDefinition &apos;{0}&apos; that was previously rejected has been resurrected..
+        /// </summary>
+        internal static string CompositionTrace_Rejection_DefinitionResurrected {
+            get {
+                return ResourceManager.GetString("CompositionTrace_Rejection_DefinitionResurrected", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot cast the underlying exported value of type &apos;{0}&apos; to type &apos;{1}&apos;..
+        /// </summary>
+        internal static string ContractMismatch_ExportedValueCannotBeCastToT {
+            get {
+                return ResourceManager.GetString("ContractMismatch_ExportedValueCannotBeCastToT", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Unable to create an Instance of the Metadata view &apos;{0}&apos; because the exporter exported the metadata  for the item &apos;{1}&apos; with the value &apos;{2}&apos; as type &apos;{3}&apos; but the view imports it as type &apos;{4}&apos;..
+        /// </summary>
+        internal static string ContractMismatch_InvalidCastOnMetadataField {
+            get {
+                return ResourceManager.GetString("ContractMismatch_InvalidCastOnMetadataField", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The implementation type for the MetadataView &apos;{0} can not be null..
+        /// </summary>
+        internal static string ContractMismatch_MetadataViewImplementationCanNotBeNull {
+            get {
+                return ResourceManager.GetString("ContractMismatch_MetadataViewImplementationCanNotBeNull", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Unable to create an Instance of the Metadata view &apos;{0}&apos; because the implementation class : &apos;{0}&apos; does not implement the MetadataView interface &apos;{1}&apos;..
+        /// </summary>
+        internal static string ContractMismatch_MetadataViewImplementationDoesNotImplementViewInterface {
+            get {
+                return ResourceManager.GetString("ContractMismatch_MetadataViewImplementationDoesNotImplementViewInterface", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Unable to create an Instance of the Metadata view &apos;{0}&apos; because the exporter exported the metadata for the item &apos;{1}&apos; with a null value and null is not a valid value for type &apos;{2}&apos;..
+        /// </summary>
+        internal static string ContractMismatch_NullReferenceOnMetadataField {
+            get {
+                return ResourceManager.GetString("ContractMismatch_NullReferenceOnMetadataField", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Directory &apos;{0}&apos; could not be found..
+        /// </summary>
+        internal static string DirectoryNotFound {
+            get {
+                return ResourceManager.GetString("DirectoryNotFound", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Member or Type &apos;{0}&apos; contains multiple metadata entries with the name &apos;{1}&apos;. The metadata entries could be coming from the ExportMetadataAttribute or from a property of a custom metadata attribute. Either remove the duplicate entries or enable the metadata entry with name &apos;{1}&apos; to allow multiple entries via the IsMultiple property on ExportMetadataAttribute or AttributeUsage.AllowMultiple on custom metadata attributes..
+        /// </summary>
+        internal static string Discovery_DuplicateMetadataNameValues {
+            get {
+                return ResourceManager.GetString("Discovery_DuplicateMetadataNameValues", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Property &apos;{0}&apos; has type &apos;{1}&apos; which is an invalid metadata type. Metadata can only contain values with a type that is available to be embedded at compile-time into attributes. For more details of what types are valid reference section 17.1.3 in the C# specification..
+        /// </summary>
+        internal static string Discovery_MetadataContainsValueWithInvalidType {
+            get {
+                return ResourceManager.GetString("Discovery_MetadataContainsValueWithInvalidType", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Member or Type &apos;{0}&apos; contains a metadata entry with the name &apos;{1}&apos;, which is a reserved metadata key name. Either remove this metadata entry or change the name associated with the entry..
+        /// </summary>
+        internal static string Discovery_ReservedMetadataNameUsed {
+            get {
+                return ResourceManager.GetString("Discovery_ReservedMetadataNameUsed", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to {0} did not originate from the ExportDefinitions property on this ComposablePart or its ComposablePartDefinition..
+        /// </summary>
+        internal static string ExportDefinitionNotOnThisComposablePart {
+            get {
+                return ResourceManager.GetString("ExportDefinitionNotOnThisComposablePart", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to ExportFactory subclass &apos;{0}&apos; can not have more than two generic parameters..
+        /// </summary>
+        internal static string ExportFactory_TooManyGenericParameters {
+            get {
+                return ResourceManager.GetString("ExportFactory_TooManyGenericParameters", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Export is not valid on an Indexer property.  The export &apos;{0}&apos; was not retrieved..
+        /// </summary>
+        internal static string ExportNotValidOnIndexers {
+            get {
+                return ResourceManager.GetString("ExportNotValidOnIndexers", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to {0} did not originate from the ImportDefinitions property on this ComposablePart or its ComposablePartDefinition..
+        /// </summary>
+        internal static string ImportDefinitionNotOnThisComposablePart {
+            get {
+                return ResourceManager.GetString("ImportDefinitionNotOnThisComposablePart", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The composition failed because it did not complete within &apos;{0:N0}&apos; iterations. This is most likely caused by a cycle in the dependency graph of a part which is marked with a non-shared creation policy..
+        /// </summary>
+        internal static string ImportEngine_ComposeTookTooManyIterations {
+            get {
+                return ResourceManager.GetString("ImportEngine_ComposeTookTooManyIterations", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The ComposablePart of type &apos;{0}&apos; cannot be recomposed because it is in an invalid state. It can only be recomposed if it has already been fully previewed or composed..
+        /// </summary>
+        internal static string ImportEngine_InvalidStateForRecomposition {
+            get {
+                return ResourceManager.GetString("ImportEngine_InvalidStateForRecomposition", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot activate part &apos;{0}&apos;..
+        /// </summary>
+        internal static string ImportEngine_PartCannotActivate {
+            get {
+                return ResourceManager.GetString("ImportEngine_PartCannotActivate", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot get export &apos;{0}&apos; from part &apos;{1}&apos;..
+        /// </summary>
+        internal static string ImportEngine_PartCannotGetExportedValue {
+            get {
+                return ResourceManager.GetString("ImportEngine_PartCannotGetExportedValue", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot set import &apos;{0}&apos; on part &apos;{1}&apos;..
+        /// </summary>
+        internal static string ImportEngine_PartCannotSetImport {
+            get {
+                return ResourceManager.GetString("ImportEngine_PartCannotSetImport", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot compose part &apos;{0}&apos; because a cycle exists in the dependencies between the exports being composed. To break this cycle, consider changing some imports from constructor to property injection..
+        /// </summary>
+        internal static string ImportEngine_PartCycle {
+            get {
+                return ResourceManager.GetString("ImportEngine_PartCycle", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Change in exports prevented by non-recomposable import &apos;{0}&apos; on part &apos;{1}&apos;..
+        /// </summary>
+        internal static string ImportEngine_PreventedByExistingImport {
+            get {
+                return ResourceManager.GetString("ImportEngine_PreventedByExistingImport", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Could not finishing composing object of type &apos;{0}&apos;. The import &apos;{1}&apos; was not satisfied..
+        /// </summary>
+        internal static string ImportNotSetOnPart {
+            get {
+                return ResourceManager.GetString("ImportNotSetOnPart", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Import is not valid on an Indexer property.  The import &apos;{0}&apos; was not satisfied..
+        /// </summary>
+        internal static string ImportNotValidOnIndexers {
+            get {
+                return ResourceManager.GetString("ImportNotValidOnIndexers", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Internal error occurred. Additional information: &apos;{0}&apos;..
+        /// </summary>
+        internal static string InternalExceptionMessage {
+            get {
+                return ResourceManager.GetString("InternalExceptionMessage", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;reflectionContext&apos; must be a type that is assignable from System.Reflection.ReflectionContext..
+        /// </summary>
+        internal static string InvalidArgument_ReflectionContext {
+            get {
+                return ResourceManager.GetString("InvalidArgument_ReflectionContext", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Metadata can only contain values with a type that is available to be embedded at compile-time into attributes. For more details of what types are valid reference section 17.1.3 in the C# specification..
+        /// </summary>
+        internal static string InvalidMetadataValue {
+            get {
+                return ResourceManager.GetString("InvalidMetadataValue", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The Type &apos;{0}&apos; supplied is not a valid Metadata View..
+        /// </summary>
+        internal static string InvalidMetadataView {
+            get {
+                return ResourceManager.GetString("InvalidMetadataView", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;definition&apos; cannot be set after Activate has been called because ImportDefinition.IsRecomposable is false..
+        /// </summary>
+        internal static string InvalidOperation_DefinitionCannotBeRecomposed {
+            get {
+                return ResourceManager.GetString("InvalidOperation_DefinitionCannotBeRecomposed", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to GetExportedValue cannot be called before prerequisite import &apos;{0}&apos; has been set..
+        /// </summary>
+        internal static string InvalidOperation_GetExportedValueBeforePrereqImportSet {
+            get {
+                return ResourceManager.GetString("InvalidOperation_GetExportedValueBeforePrereqImportSet", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to A call to Compose occurred during a call to Compose on the same CompositionContainer object. Use the IsComposing property on CompositionContainer to ensure a composition is not already in progress before calling Compose..
+        /// </summary>
+        internal static string InvalidOperationReentrantCompose {
+            get {
+                return ResourceManager.GetString("InvalidOperationReentrantCompose", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to A CreationPolicy of &apos;(0)&apos; can not be applied to an Import that is not an ExportFactory..
+        /// </summary>
+        internal static string InvalidPartCreationPolicyOnImport {
+            get {
+                return ResourceManager.GetString("InvalidPartCreationPolicyOnImport", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to A CreationPolicy of &apos;{0}&apos; can not be applied to a ComposablePart..
+        /// </summary>
+        internal static string InvalidPartCreationPolicyOnPart {
+            get {
+                return ResourceManager.GetString("InvalidPartCreationPolicyOnPart", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The MetadataView &apos;{0}&apos; is invalid because property &apos;{1}&apos; has a property set method..
+        /// </summary>
+        internal static string InvalidSetterOnMetadataField {
+            get {
+                return ResourceManager.GetString("InvalidSetterOnMetadataField", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Accessors must not be null (Nothing in Visual Basic)..
+        /// </summary>
+        internal static string LazyMemberInfo_AccessorsNull {
+            get {
+                return ResourceManager.GetString("LazyMemberInfo_AccessorsNull", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to A member of type &apos;{0}&apos; must have exactly a single accessor of type &apos;{0}&apos;.
+        /// </summary>
+        internal static string LazyMemberInfo_InvalidAccessorOnSimpleMember {
+            get {
+                return ResourceManager.GetString("LazyMemberInfo_InvalidAccessorOnSimpleMember", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to All event accessors must be methods..
+        /// </summary>
+        internal static string LazyMemberinfo_InvalidEventAccessors_AccessorType {
+            get {
+                return ResourceManager.GetString("LazyMemberinfo_InvalidEventAccessors_AccessorType", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to An event must have exactly three accessors..
+        /// </summary>
+        internal static string LazyMemberInfo_InvalidEventAccessors_Cardinality {
+            get {
+                return ResourceManager.GetString("LazyMemberInfo_InvalidEventAccessors_Cardinality", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to All property accessors must be methods..
+        /// </summary>
+        internal static string LazyMemberinfo_InvalidPropertyAccessors_AccessorType {
+            get {
+                return ResourceManager.GetString("LazyMemberinfo_InvalidPropertyAccessors_AccessorType", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to A property must have exactly two accessors..
+        /// </summary>
+        internal static string LazyMemberInfo_InvalidPropertyAccessors_Cardinality {
+            get {
+                return ResourceManager.GetString("LazyMemberInfo_InvalidPropertyAccessors_Cardinality", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to A member must have at least one accessor..
+        /// </summary>
+        internal static string LazyMemberInfo_NoAccessors {
+            get {
+                return ResourceManager.GetString("LazyMemberInfo_NoAccessors", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The lazily evaluated value of type &apos;{0}&apos; passed to the ReflectionModelServices API as part of the argument &apos;{1}&apos; must not return null (Nothing in Visual Basic)..
+        /// </summary>
+        internal static string LazyServices_LazyResolvesToNull {
+            get {
+                return ResourceManager.GetString("LazyServices_LazyResolvesToNull", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to This export does not support the metadata item &apos;{0}&apos;..
+        /// </summary>
+        internal static string MetadataItemNotSupported {
+            get {
+                return ResourceManager.GetString("MetadataItemNotSupported", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The {0} member must be overridden by a derived class..
+        /// </summary>
+        internal static string NotImplemented_NotOverriddenByDerived {
+            get {
+                return ResourceManager.GetString("NotImplemented_NotOverriddenByDerived", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to This CompositionService does not support catalog changes..
+        /// </summary>
+        internal static string NotSupportedCatalogChanges {
+            get {
+                return ResourceManager.GetString("NotSupportedCatalogChanges", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Interface &apos;{0}&apos; is not a valid MetadataView; MetadataViews do not support non-public interfaces, and interfaces that contain members that are not properties..
+        /// </summary>
+        internal static string NotSupportedInterfaceMetadataView {
+            get {
+                return ResourceManager.GetString("NotSupportedInterfaceMetadataView", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The underlying dictionary is read-only..
+        /// </summary>
+        internal static string NotSupportedReadOnlyDictionary {
+            get {
+                return ResourceManager.GetString("NotSupportedReadOnlyDictionary", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to This property cannot be set after the object&apos;s public surface has been accessed..
+        /// </summary>
+        internal static string ObjectAlreadyInitialized {
+            get {
+                return ResourceManager.GetString("ObjectAlreadyInitialized", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to This object has not been initialized - the property &apos;{0}&apos; must be set..
+        /// </summary>
+        internal static string ObjectMustBeInitialized {
+            get {
+                return ResourceManager.GetString("ObjectMustBeInitialized", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Currently composing another batch in this ComposablePartExportProvider. Only one batch can be composed at a time..
+        /// </summary>
+        internal static string ReentrantCompose {
+            get {
+                return ResourceManager.GetString("ReentrantCompose", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to A ReflectionContext must have a default constructor..
+        /// </summary>
+        internal static string ReflectionContext_Requires_DefaultConstructor {
+            get {
+                return ResourceManager.GetString("ReflectionContext_Requires_DefaultConstructor", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The type specified in the ReflectionContextDiscoveryAttribute must be assignable to System.Reflection.ReflectionContext..
+        /// </summary>
+        internal static string ReflectionContext_Type_Required {
+            get {
+                return ResourceManager.GetString("ReflectionContext_Type_Required", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot get the value of property &apos;{0}&apos;, because the member is not readable. The property must have an accessible getter..
+        /// </summary>
+        internal static string ReflectionModel_ExportNotReadable {
+            get {
+                return ResourceManager.GetString("ReflectionModel_ExportNotReadable", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to An exception occurred while trying to get the value of property &apos;{0}&apos;..
+        /// </summary>
+        internal static string ReflectionModel_ExportThrewException {
+            get {
+                return ResourceManager.GetString("ReflectionModel_ExportThrewException", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot populate the collection &apos;{0}&apos; because an exception occurred while calling the Add method on the type &apos;{1}&apos;..
+        /// </summary>
+        internal static string ReflectionModel_ImportCollectionAddThrewException {
+            get {
+                return ResourceManager.GetString("ReflectionModel_ImportCollectionAddThrewException", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot populate the collection &apos;{0}&apos; because an exception occurred while calling the Clear method on the type &apos;{1}&apos;..
+        /// </summary>
+        internal static string ReflectionModel_ImportCollectionClearThrewException {
+            get {
+                return ResourceManager.GetString("ReflectionModel_ImportCollectionClearThrewException", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot populate the collection &apos;{0}&apos; because an exception occurred while calling the default constructor on the type &apos;{1}&apos;..
+        /// </summary>
+        internal static string ReflectionModel_ImportCollectionConstructionThrewException {
+            get {
+                return ResourceManager.GetString("ReflectionModel_ImportCollectionConstructionThrewException", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot populate the collection &apos;{0}&apos; because an exception occurred while trying to access the collection value. If the collection is not IEnumerable&lt;T&gt; or T[] it must implement ICollection&lt;T&gt; and be either pre-initialized or be writable with a default constructor..
+        /// </summary>
+        internal static string ReflectionModel_ImportCollectionGetThrewException {
+            get {
+                return ResourceManager.GetString("ReflectionModel_ImportCollectionGetThrewException", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot populate the collection &apos;{0}&apos; because an exception occurred while reading the IsReadOnly property on the type &apos;{1}&apos;..
+        /// </summary>
+        internal static string ReflectionModel_ImportCollectionIsReadOnlyThrewException {
+            get {
+                return ResourceManager.GetString("ReflectionModel_ImportCollectionIsReadOnlyThrewException", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot populate the collection &apos;{0}&apos; because it does not implement ICollection&lt;T&gt; or is read-only. If the collection is not IEnumerable&lt;T&gt; or T[] it must implement ICollection&lt;T&gt; and be either pre-initialized or be writable with a default constructor..
+        /// </summary>
+        internal static string ReflectionModel_ImportCollectionNotWritable {
+            get {
+                return ResourceManager.GetString("ReflectionModel_ImportCollectionNotWritable", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot populate the value of enumerable member &apos;{0}&apos; because it is null (Nothing in Visual Basic). If the collection is not IEnumerable&lt;T&gt; or T[] it must implement ICollection&lt;T&gt; and be either pre-initialized or be writable with a default constructor..
+        /// </summary>
+        internal static string ReflectionModel_ImportCollectionNull {
+            get {
+                return ResourceManager.GetString("ReflectionModel_ImportCollectionNull", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The importing constructor on type &apos;{0}&apos; is using ImportManyAttribute on parameter &apos;{1}&apos; with a non-assignable type. On constructor parameters the ImportManyAttribute only supports importing into types T[] or IEnumerable&lt;T&gt;..
+        /// </summary>
+        internal static string ReflectionModel_ImportManyOnParameterCanOnlyBeAssigned {
+            get {
+                return ResourceManager.GetString("ReflectionModel_ImportManyOnParameterCanOnlyBeAssigned", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The export &apos;{0}&apos; is not assignable to type &apos;{1}&apos;..
+        /// </summary>
+        internal static string ReflectionModel_ImportNotAssignableFromExport {
+            get {
+                return ResourceManager.GetString("ReflectionModel_ImportNotAssignableFromExport", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot set the value of &apos;{0}&apos; because the member is not writable. If the member is a property, it must have an accessible setter; otherwise, if it is a field, it must not be read-only..
+        /// </summary>
+        internal static string ReflectionModel_ImportNotWritable {
+            get {
+                return ResourceManager.GetString("ReflectionModel_ImportNotWritable", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to An exception occurred while trying to set the value of property &apos;{0}&apos;..
+        /// </summary>
+        internal static string ReflectionModel_ImportThrewException {
+            get {
+                return ResourceManager.GetString("ReflectionModel_ImportThrewException", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to ExportDefinition of type &apos;{0}&apos; cannot be used in this context. Only export definitions produced by the ReflectionModelServices.CreateExportDefinition are supported..
+        /// </summary>
+        internal static string ReflectionModel_InvalidExportDefinition {
+            get {
+                return ResourceManager.GetString("ReflectionModel_InvalidExportDefinition", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to ImportDefinition of type &apos;{0}&apos; cannot be used in this context. Only import definitions produced by the ReflectionModelServices.CreateImportDefinition are supported..
+        /// </summary>
+        internal static string ReflectionModel_InvalidImportDefinition {
+            get {
+                return ResourceManager.GetString("ReflectionModel_InvalidImportDefinition", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to ImportDefinition of type &apos;{0}&apos; cannot be used in this context. Only import definitions produced by the ReflectionModelServices.CreateImportDefinition based on members are supported. Use ReflectionModelServices.IsImportingParameter to determine whether a given import definition is based on a member or a parameter..
+        /// </summary>
+        internal static string ReflectionModel_InvalidMemberImportDefinition {
+            get {
+                return ResourceManager.GetString("ReflectionModel_InvalidMemberImportDefinition", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to ImportDefinition of type &apos;{0}&apos; cannot be used in this context. Only import definitions produced by the ReflectionModelServices.CreateImportDefinition based on parameters are supported. Use ReflectionModelServices.IsImportingParameter to determine whether a given import definition is based on a member or a parameter..
+        /// </summary>
+        internal static string ReflectionModel_InvalidParameterImportDefinition {
+            get {
+                return ResourceManager.GetString("ReflectionModel_InvalidParameterImportDefinition", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to ComposablePartDefinition of type &apos;{0}&apos; cannot be used in this context. Only part definitions produced by the ReflectionModelServices.CreatePartDefinition are supported..
+        /// </summary>
+        internal static string ReflectionModel_InvalidPartDefinition {
+            get {
+                return ResourceManager.GetString("ReflectionModel_InvalidPartDefinition", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot create an instance of type &apos;{0}&apos; because a constructor could not be selected for construction. Ensure that the type either has a default constructor, or a single constructor marked with the &apos;System.ComponentModel.Composition.ImportingConstructorAttribute&apos;..
+        /// </summary>
+        internal static string ReflectionModel_PartConstructorMissing {
+            get {
+                return ResourceManager.GetString("ReflectionModel_PartConstructorMissing", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to An exception occurred while trying to create an instance of type &apos;{0}&apos;..
+        /// </summary>
+        internal static string ReflectionModel_PartConstructorThrewException {
+            get {
+                return ResourceManager.GetString("ReflectionModel_PartConstructorThrewException", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to An exception occurred while calling the &apos;OnImportsSatisfied&apos; method on type &apos;{0}&apos;..
+        /// </summary>
+        internal static string ReflectionModel_PartOnImportsSatisfiedThrewException {
+            get {
+                return ResourceManager.GetString("ReflectionModel_PartOnImportsSatisfiedThrewException", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to {0} (Types=&apos;{1}&apos;)..
+        /// </summary>
+        internal static string TypeCatalog_DisplayNameFormat {
+            get {
+                return ResourceManager.GetString("TypeCatalog_DisplayNameFormat", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to &lt;Empty&gt;.
+        /// </summary>
+        internal static string TypeCatalog_Empty {
+            get {
+                return ResourceManager.GetString("TypeCatalog_Empty", resourceCulture);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Strings.resx b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Strings.resx
new file mode 100644
index 00000000000..27fcfcaff3e
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/Strings.resx
@@ -0,0 +1,447 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <data name="ArgumentException_EmptyString" xml:space="preserve">
+    <value>'{0}' cannot be an empty string ("").</value>
+  </data>
+  <data name="ArgumentOutOfRange_InvalidEnum" xml:space="preserve">
+    <value>The value of argument '{0}' ({1}) is invalid for Enum type '{2}'.</value>
+  </data>
+  <data name="ArgumentValueType" xml:space="preserve">
+    <value>The argument was a value type which is not supported.</value>
+  </data>
+  <data name="Argument_AssemblyReflectionOnly" xml:space="preserve">
+    <value>'{0}' is a reflection-only assembly which is not supported.</value>
+  </data>
+  <data name="Argument_NullElement" xml:space="preserve">
+    <value>'{0}' cannot contain a null (Nothing in Visual Basic) element.</value>
+  </data>
+  <data name="AssemblyFileNotFoundOrWrongType" xml:space="preserve">
+    <value>Assembly file {0} is either not found or not a dll or exe file.</value>
+  </data>
+  <data name="CardinalityMismatch_NoExports" xml:space="preserve">
+    <value>No exports were found that match the constraint: {0}</value>
+  </data>
+  <data name="CardinalityMismatch_TooManyExports" xml:space="preserve">
+    <value>More than one export was found that matches the constraint: {0}</value>
+  </data>
+  <data name="ImportEngine_ComposeTookTooManyIterations" xml:space="preserve">
+    <value>The composition failed because it did not complete within '{0:N0}' iterations. This is most likely caused by a cycle in the dependency graph of a part which is marked with a non-shared creation policy.</value>
+  </data>
+  <data name="ContractMismatch_ExportedValueCannotBeCastToT" xml:space="preserve">
+    <value>Cannot cast the underlying exported value of type '{0}' to type '{1}'.</value>
+  </data>
+  <data name="DirectoryNotFound" xml:space="preserve">
+    <value>Directory '{0}' could not be found.</value>
+  </data>
+  <data name="ReflectionModel_PartConstructorThrewException" xml:space="preserve">
+    <value>An exception occurred while trying to create an instance of type '{0}'.</value>
+  </data>
+  <data name="ReflectionModel_ExportThrewException" xml:space="preserve">
+    <value>An exception occurred while trying to get the value of property '{0}'.</value>
+  </data>
+  <data name="ReflectionModel_PartOnImportsSatisfiedThrewException" xml:space="preserve">
+    <value>An exception occurred while calling the 'OnImportsSatisfied' method on type '{0}'.</value>
+  </data>
+  <data name="ReflectionModel_ImportThrewException" xml:space="preserve">
+    <value>An exception occurred while trying to set the value of property '{0}'.</value>
+  </data>
+  <data name="ExportDefinitionNotOnThisComposablePart" xml:space="preserve">
+    <value>{0} did not originate from the ExportDefinitions property on this ComposablePart or its ComposablePartDefinition.</value>
+  </data>
+  <data name="ReflectionModel_ImportCollectionNotWritable" xml:space="preserve">
+    <value>Cannot populate the collection '{0}' because it does not implement ICollection&lt;T&gt; or is read-only. If the collection is not IEnumerable&lt;T&gt; or T[] it must implement ICollection&lt;T&gt; and be either pre-initialized or be writable with a default constructor.</value>
+  </data>
+  <data name="ReflectionModel_ImportCollectionNull" xml:space="preserve">
+    <value>Cannot populate the value of enumerable member '{0}' because it is null (Nothing in Visual Basic). If the collection is not IEnumerable&lt;T&gt; or T[] it must implement ICollection&lt;T&gt; and be either pre-initialized or be writable with a default constructor.</value>
+  </data>
+  <data name="ImportEngine_PartCycle" xml:space="preserve">
+    <value>Cannot compose part '{0}' because a cycle exists in the dependencies between the exports being composed. To break this cycle, consider changing some imports from constructor to property injection.</value>
+  </data>
+  <data name="ImportDefinitionNotOnThisComposablePart" xml:space="preserve">
+    <value>{0} did not originate from the ImportDefinitions property on this ComposablePart or its ComposablePartDefinition.</value>
+  </data>
+  <data name="ImportNotSetOnPart" xml:space="preserve">
+    <value>Could not finishing composing object of type '{0}'. The import '{1}' was not satisfied.</value>
+  </data>
+  <data name="ReflectionModel_ImportNotWritable" xml:space="preserve">
+    <value>Cannot set the value of '{0}' because the member is not writable. If the member is a property, it must have an accessible setter; otherwise, if it is a field, it must not be read-only.</value>
+  </data>
+  <data name="InternalExceptionMessage" xml:space="preserve">
+    <value>Internal error occurred. Additional information: '{0}'.</value>
+  </data>
+  <data name="InvalidMetadataView" xml:space="preserve">
+    <value>The Type '{0}' supplied is not a valid Metadata View.</value>
+  </data>
+  <data name="InvalidOperationReentrantCompose" xml:space="preserve">
+    <value>A call to Compose occurred during a call to Compose on the same CompositionContainer object. Use the IsComposing property on CompositionContainer to ensure a composition is not already in progress before calling Compose.</value>
+  </data>
+  <data name="MetadataItemNotSupported" xml:space="preserve">
+    <value>This export does not support the metadata item '{0}'.</value>
+  </data>
+  <data name="NotSupportedInterfaceMetadataView" xml:space="preserve">
+    <value>Interface '{0}' is not a valid MetadataView; MetadataViews do not support non-public interfaces, and interfaces that contain members that are not properties.</value>
+  </data>
+  <data name="ReflectionModel_PartConstructorMissing" xml:space="preserve">
+    <value>Cannot create an instance of type '{0}' because a constructor could not be selected for construction. Ensure that the type either has a default constructor, or a single constructor marked with the 'System.ComponentModel.Composition.ImportingConstructorAttribute'.</value>
+  </data>
+  <data name="NotImplemented_NotOverriddenByDerived" xml:space="preserve">
+    <value>The {0} member must be overridden by a derived class.</value>
+  </data>
+  <data name="NotSupportedReadOnlyDictionary" xml:space="preserve">
+    <value>The underlying dictionary is read-only.</value>
+  </data>
+  <data name="ObjectAlreadyInitialized" xml:space="preserve">
+    <value>This property cannot be set after the object's public surface has been accessed.</value>
+  </data>
+  <data name="ObjectMustBeInitialized" xml:space="preserve">
+    <value>This object has not been initialized - the property '{0}' must be set.</value>
+  </data>
+  <data name="ReflectionModel_ImportNotAssignableFromExport" xml:space="preserve">
+    <value>The export '{0}' is not assignable to type '{1}'.</value>
+  </data>
+  <data name="ReflectionModel_ExportNotReadable" xml:space="preserve">
+    <value>Cannot get the value of property '{0}', because the member is not readable. The property must have an accessible getter.</value>
+  </data>
+  <data name="Argument_ElementReflectionOnlyType" xml:space="preserve">
+    <value>'{0}' contains a reflection-only type which is not supported.</value>
+  </data>
+  <data name="InvalidOperation_DefinitionCannotBeRecomposed" xml:space="preserve">
+    <value>'definition' cannot be set after Activate has been called because ImportDefinition.IsRecomposable is false.</value>
+  </data>
+  <data name="Argument_ExportsEmpty" xml:space="preserve">
+    <value>'exports' cannot be empty when ImportDefinition.ImportCardinality is ImportCardinality.ExactlyOne.</value>
+  </data>
+  <data name="Argument_ExportsTooMany" xml:space="preserve">
+    <value>'exports' cannot contain more than one element when ImportDefinition.ImportCardinality is ImportCardinality.ZeroOrOne or ImportCardinality.ExactlyOne.</value>
+  </data>
+  <data name="CompositionElement_UnknownOrigin" xml:space="preserve">
+    <value>Unknown Origin</value>
+  </data>
+  <data name="ImportEngine_PartCannotActivate" xml:space="preserve">
+    <value>Cannot activate part '{0}'.</value>
+  </data>
+  <data name="ImportEngine_PartCannotSetImport" xml:space="preserve">
+    <value>Cannot set import '{0}' on part '{1}'.</value>
+  </data>
+  <data name="ImportEngine_PartCannotGetExportedValue" xml:space="preserve">
+    <value>Cannot get export '{0}' from part '{1}'.</value>
+  </data>
+  <data name="TypeCatalog_Empty" xml:space="preserve">
+    <value>&lt;Empty&gt;</value>
+  </data>
+  <data name="InvalidOperation_GetExportedValueBeforePrereqImportSet" xml:space="preserve">
+    <value>GetExportedValue cannot be called before prerequisite import '{0}' has been set.</value>
+  </data>
+  <data name="CompositionException_ErrorPrefix" xml:space="preserve">
+    <value>Resulting in:</value>
+  </data>
+  <data name="CompositionException_MultipleErrorsWithMultiplePaths" xml:space="preserve">
+    <value>The composition produced multiple composition errors, with {0:N0} root causes. The root causes are provided below.</value>
+  </data>
+  <data name="CompositionException_ReviewErrorProperty" xml:space="preserve">
+    <value>Review the CompositionException.Errors property for more detailed information.</value>
+  </data>
+  <data name="CompositionException_SingleErrorWithMultiplePaths" xml:space="preserve">
+    <value>The composition produced a single composition error, with {0:N0} root causes. The root causes are provided below.</value>
+  </data>
+  <data name="CompositionException_SingleErrorWithSinglePath" xml:space="preserve">
+    <value>The composition produced a single composition error. The root cause is provided below.</value>
+  </data>
+  <data name="ReflectionModel_ImportCollectionGetThrewException" xml:space="preserve">
+    <value>Cannot populate the collection '{0}' because an exception occurred while trying to access the collection value. If the collection is not IEnumerable&lt;T&gt; or T[] it must implement ICollection&lt;T&gt; and be either pre-initialized or be writable with a default constructor.</value>
+  </data>
+  <data name="ReflectionModel_ImportCollectionAddThrewException" xml:space="preserve">
+    <value>Cannot populate the collection '{0}' because an exception occurred while calling the Add method on the type '{1}'.</value>
+  </data>
+  <data name="ReflectionModel_ImportCollectionClearThrewException" xml:space="preserve">
+    <value>Cannot populate the collection '{0}' because an exception occurred while calling the Clear method on the type '{1}'.</value>
+  </data>
+  <data name="ReflectionModel_ImportCollectionIsReadOnlyThrewException" xml:space="preserve">
+    <value>Cannot populate the collection '{0}' because an exception occurred while reading the IsReadOnly property on the type '{1}'.</value>
+  </data>
+  <data name="ReflectionModel_ImportCollectionConstructionThrewException" xml:space="preserve">
+    <value>Cannot populate the collection '{0}' because an exception occurred while calling the default constructor on the type '{1}'.</value>
+  </data>
+  <data name="CompositionTrace_Discovery_MemberMarkedWithMultipleImportAndImportMany" xml:space="preserve">
+    <value>The member or parameter '{0}' is marked with multiple Import and ImportMany attributes. Only the first attribute encountered will be respected.</value>
+  </data>
+  <data name="Discovery_MetadataContainsValueWithInvalidType" xml:space="preserve">
+    <value>Property '{0}' has type '{1}' which is an invalid metadata type. Metadata can only contain values with a type that is available to be embedded at compile-time into attributes. For more details of what types are valid reference section 17.1.3 in the C# specification.</value>
+  </data>
+  <data name="Discovery_DuplicateMetadataNameValues" xml:space="preserve">
+    <value>Member or Type '{0}' contains multiple metadata entries with the name '{1}'. The metadata entries could be coming from the ExportMetadataAttribute or from a property of a custom metadata attribute. Either remove the duplicate entries or enable the metadata entry with name '{1}' to allow multiple entries via the IsMultiple property on ExportMetadataAttribute or AttributeUsage.AllowMultiple on custom metadata attributes.</value>
+  </data>
+  <data name="Discovery_ReservedMetadataNameUsed" xml:space="preserve">
+    <value>Member or Type '{0}' contains a metadata entry with the name '{1}', which is a reserved metadata key name. Either remove this metadata entry or change the name associated with the entry.</value>
+  </data>
+  <data name="ReflectionModel_InvalidExportDefinition" xml:space="preserve">
+    <value>ExportDefinition of type '{0}' cannot be used in this context. Only export definitions produced by the ReflectionModelServices.CreateExportDefinition are supported.</value>
+  </data>
+  <data name="ImportEngine_PreventedByExistingImport" xml:space="preserve">
+    <value>Change in exports prevented by non-recomposable import '{0}' on part '{1}'.</value>
+  </data>
+  <data name="ReflectionModel_InvalidImportDefinition" xml:space="preserve">
+    <value>ImportDefinition of type '{0}' cannot be used in this context. Only import definitions produced by the ReflectionModelServices.CreateImportDefinition are supported.</value>
+  </data>
+  <data name="ReflectionModel_InvalidPartDefinition" xml:space="preserve">
+    <value>ComposablePartDefinition of type '{0}' cannot be used in this context. Only part definitions produced by the ReflectionModelServices.CreatePartDefinition are supported.</value>
+  </data>
+  <data name="ArgumentOutOfRange_InvalidEnumInSet" xml:space="preserve">
+    <value>The value of argument '{0}' ({1}) is not supported. Allowed values are : '{2}'.</value>
+  </data>
+  <data name="ReflectionModel_InvalidMemberImportDefinition" xml:space="preserve">
+    <value>ImportDefinition of type '{0}' cannot be used in this context. Only import definitions produced by the ReflectionModelServices.CreateImportDefinition based on members are supported. Use ReflectionModelServices.IsImportingParameter to determine whether a given import definition is based on a member or a parameter.</value>
+  </data>
+  <data name="ReflectionModel_InvalidParameterImportDefinition" xml:space="preserve">
+    <value>ImportDefinition of type '{0}' cannot be used in this context. Only import definitions produced by the ReflectionModelServices.CreateImportDefinition based on parameters are supported. Use ReflectionModelServices.IsImportingParameter to determine whether a given import definition is based on a member or a parameter.</value>
+  </data>
+  <data name="LazyMemberInfo_AccessorsNull" xml:space="preserve">
+    <value>Accessors must not be null (Nothing in Visual Basic).</value>
+  </data>
+  <data name="LazyMemberInfo_InvalidAccessorOnSimpleMember" xml:space="preserve">
+    <value>A member of type '{0}' must have exactly a single accessor of type '{0}'</value>
+  </data>
+  <data name="LazyMemberinfo_InvalidEventAccessors_AccessorType" xml:space="preserve">
+    <value>All event accessors must be methods.</value>
+  </data>
+  <data name="LazyMemberInfo_InvalidEventAccessors_Cardinality" xml:space="preserve">
+    <value>An event must have exactly three accessors.</value>
+  </data>
+  <data name="LazyMemberinfo_InvalidPropertyAccessors_AccessorType" xml:space="preserve">
+    <value>All property accessors must be methods.</value>
+  </data>
+  <data name="LazyMemberInfo_InvalidPropertyAccessors_Cardinality" xml:space="preserve">
+    <value>A property must have exactly two accessors.</value>
+  </data>
+  <data name="LazyMemberInfo_NoAccessors" xml:space="preserve">
+    <value>A member must have at least one accessor.</value>
+  </data>
+  <data name="LazyServices_LazyResolvesToNull" xml:space="preserve">
+    <value>The lazily evaluated value of type '{0}' passed to the ReflectionModelServices API as part of the argument '{1}' must not return null (Nothing in Visual Basic).</value>
+  </data>
+  <data name="InvalidMetadataValue" xml:space="preserve">
+    <value>Metadata can only contain values with a type that is available to be embedded at compile-time into attributes. For more details of what types are valid reference section 17.1.3 in the C# specification.</value>
+  </data>
+  <data name="ContractMismatch_InvalidCastOnMetadataField" xml:space="preserve">
+    <value>Unable to create an Instance of the Metadata view '{0}' because the exporter exported the metadata  for the item '{1}' with the value '{2}' as type '{3}' but the view imports it as type '{4}'.</value>
+  </data>
+  <data name="ContractMismatch_NullReferenceOnMetadataField" xml:space="preserve">
+    <value>Unable to create an Instance of the Metadata view '{0}' because the exporter exported the metadata for the item '{1}' with a null value and null is not a valid value for type '{2}'.</value>
+  </data>
+  <data name="InvalidSetterOnMetadataField" xml:space="preserve">
+    <value>The MetadataView '{0}' is invalid because property '{1}' has a property set method.</value>
+  </data>
+  <data name="CompositionException_ChangesRejected" xml:space="preserve">
+    <value>The composition remains unchanged. The changes were rejected because of the following error(s): {0}</value>
+  </data>
+  <data name="ImportEngine_InvalidStateForRecomposition" xml:space="preserve">
+    <value>The ComposablePart of type '{0}' cannot be recomposed because it is in an invalid state. It can only be recomposed if it has already been fully previewed or composed.</value>
+  </data>
+  <data name="AtomicComposition_AlreadyCompleted" xml:space="preserve">
+    <value>The atomicComposition can no longer be changed because the atomicComposition has already been completed.</value>
+  </data>
+  <data name="AtomicComposition_PartOfAnotherAtomicComposition" xml:space="preserve">
+    <value>The atomicComposition contains another inner atomicComposition and cannot be changed until the that inner atomicComposition has been completed.</value>
+  </data>
+  <data name="AtomicComposition_AlreadyNested" xml:space="preserve">
+    <value>The atomicComposition already contains an inner atomicComposition and cannot contain more than one atomicComposition at a time.</value>
+  </data>
+  <data name="ReentrantCompose" xml:space="preserve">
+    <value>Currently composing another batch in this ComposablePartExportProvider. Only one batch can be composed at a time.</value>
+  </data>
+  <data name="ReflectionModel_ImportManyOnParameterCanOnlyBeAssigned" xml:space="preserve">
+    <value>The importing constructor on type '{0}' is using ImportManyAttribute on parameter '{1}' with a non-assignable type. On constructor parameters the ImportManyAttribute only supports importing into types T[] or IEnumerable&lt;T&gt;.</value>
+  </data>
+  <data name="CompositionException_ElementPrefix" xml:space="preserve">
+    <value>Element: {0}</value>
+  </data>
+  <data name="CompositionException_OriginSeparator" xml:space="preserve">
+    <value>--&gt; </value>
+  </data>
+  <data name="CompositionTrace_Rejection_DefinitionRejected" xml:space="preserve">
+    <value>The ComposablePartDefinition '{0}' has been rejected. {1}</value>
+  </data>
+  <data name="CompositionTrace_Rejection_DefinitionResurrected" xml:space="preserve">
+    <value>The ComposablePartDefinition '{0}' that was previously rejected has been resurrected.</value>
+  </data>
+  <data name="CompositionTrace_Discovery_AssemblyLoadFailed" xml:space="preserve">
+    <value>The catalog '{0}' could not load assembly '{1}'. {2}</value>
+  </data>
+  <data name="CompositionTrace_Discovery_DefinitionContainsNoExports" xml:space="preserve">
+    <value>The ComposablePartDefinition '{0}' was ignored because it contains no exports.</value>
+  </data>
+  <data name="CompositionTrace_Discovery_DefinitionMarkedWithPartNotDiscoverableAttribute" xml:space="preserve">
+    <value>The ComposablePartDefinition '{0}' was ignored because it was marked with PartNotDiscoverableAttribute.</value>
+  </data>
+  <data name="CompositionException_MetadataViewInvalidConstructor" xml:space="preserve">
+    <value>Unable to create an instance of the Metadata view '{0}' because a constructor could not be selected.  Ensure that the type implements a constructor which takes an argument of type IDictionary&lt;string, object&gt;.</value>
+  </data>
+  <data name="CompositionException_PathsCountSeparator" xml:space="preserve">
+    <value>)</value>
+  </data>
+  <data name="CompositionException_OriginFormat" xml:space="preserve">
+    <value> {0} {1}</value>
+  </data>
+  <data name="TypeCatalog_DisplayNameFormat" xml:space="preserve">
+    <value>{0} (Types='{1}').</value>
+  </data>
+  <data name="ImportNotValidOnIndexers" xml:space="preserve">
+    <value>Import is not valid on an Indexer property.  The import '{0}' was not satisfied.</value>
+  </data>
+  <data name="ExportNotValidOnIndexers" xml:space="preserve">
+    <value>Export is not valid on an Indexer property.  The export '{0}' was not retrieved.</value>
+  </data>
+  <data name="ReflectionContext_Requires_DefaultConstructor" xml:space="preserve">
+    <value>A ReflectionContext must have a default constructor.</value>
+  </data>
+  <data name="ReflectionContext_Type_Required" xml:space="preserve">
+    <value>The type specified in the ReflectionContextDiscoveryAttribute must be assignable to System.Reflection.ReflectionContext.</value>
+  </data>
+  <data name="CompositionTrace_Discovery_DefinitionMismatchedExportArity" xml:space="preserve">
+    <value>The composable part definition '{0}' was ignored because the export '{1}' has different generic parameters than the part type.</value>
+  </data>
+  <data name="InvalidArgument_ReflectionContext" xml:space="preserve">
+    <value>'reflectionContext' must be a type that is assignable from System.Reflection.ReflectionContext.</value>
+  </data>
+  <data name="Argument_ReflectionContextReturnsReflectionOnlyType" xml:space="preserve">
+    <value>'{0}' returns a mapped type that is a reflection-only type which is not supported.</value>
+  </data>
+  <data name="ContractMismatch_MetadataViewImplementationDoesNotImplementViewInterface" xml:space="preserve">
+    <value>Unable to create an Instance of the Metadata view '{0}' because the implementation class : '{0}' does not implement the MetadataView interface '{1}'.</value>
+  </data>
+  <data name="ContractMismatch_MetadataViewImplementationCanNotBeNull" xml:space="preserve">
+    <value>The implementation type for the MetadataView '{0} can not be null.</value>
+  </data>
+  <data name="InvalidPartCreationPolicyOnImport" xml:space="preserve">
+    <value>A CreationPolicy of '(0)' can not be applied to an Import that is not an ExportFactory.</value>
+  </data>
+  <data name="InvalidPartCreationPolicyOnPart" xml:space="preserve">
+    <value>A CreationPolicy of '{0}' can not be applied to a ComposablePart.</value>
+  </data>
+  <data name="ExportFactory_TooManyGenericParameters" xml:space="preserve">
+    <value>ExportFactory subclass '{0}' can not have more than two generic parameters.</value>
+  </data>
+  <data name="CatalogMutation_Invalid" xml:space="preserve">
+    <value>ScopingPolicyCatalog does not support catalog mutation.</value>
+  </data>
+  <data name="NotSupportedCatalogChanges" xml:space="preserve">
+    <value>This CompositionService does not support catalog changes.</value>
+  </data>
+</root>
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/SuppressMessages.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/SuppressMessages.cs
new file mode 100644
index 00000000000..4c57e17a2c8
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/SuppressMessages.cs
@@ -0,0 +1,10 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Diagnostics.CodeAnalysis;
+
+[assembly: SuppressMessage("Microsoft.Design", "CA1020:AvoidNamespacesWithFewTypes", Scope = "namespace", Target = "System.ComponentModel.Composition.ReflectionModel")]
+[assembly: SuppressMessage("Microsoft.Design", "CA1020:AvoidNamespacesWithFewTypes", Scope = "namespace", Target = "System")]
+[assembly: SuppressMessage("Microsoft.MSInternal", "CA905:SystemNamespacesRequireApproval", Scope = "namespace", Target = "System.ComponentModel.Composition.ReflectionModel", Justification = "Approved by Framework")]
+
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/SuppressMessagesBaselined.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/SuppressMessagesBaselined.cs
new file mode 100644
index 00000000000..b190f952e56
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/SuppressMessagesBaselined.cs
@@ -0,0 +1,54 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Diagnostics.CodeAnalysis;
+
+// The following are untriaged violations, do not add to this list unless you hit a bug in Code Analysis. Any explicitly 
+// suppressed violations should either be applied against the member or type itself, or if raised against a namespace, 
+// resource or assembly, placed in SuppressMessages.cs.
+
+// Code Analysis Bug: ValidateArgumentsOfPublicMethods should not fire on protected members
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Hosting.ComposablePartExportProvider.#GetExportsCore(System.ComponentModel.Composition.Primitives.ImportDefinition,System.ComponentModel.Composition.Hosting.AtomicComposition)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Hosting.AggregateExportProvider.#GetExportsCore(System.ComponentModel.Composition.Primitives.ImportDefinition,System.ComponentModel.Composition.Hosting.AtomicComposition)")]
+
+// Code Analysis Bug: ValidateArgumentsOfPublicMethods should not fire on usage of Requires.NotNull
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.AttributedModelServices.#AddExportedValue`1(System.ComponentModel.Composition.Hosting.CompositionBatch,System.String,!!0)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.AttributedModelServices.#AddPart(System.ComponentModel.Composition.Hosting.CompositionBatch,System.Object)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.AttributedModelServices.#ComposeExportedValue`1(System.ComponentModel.Composition.Hosting.CompositionContainer,System.String,!!0)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.AttributedModelServices.#ComposeExportedValue`1(System.ComponentModel.Composition.Hosting.CompositionContainer,!!0)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.AttributedModelServices.#ComposeParts(System.ComponentModel.Composition.Hosting.CompositionContainer,System.Object[])")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.AttributedModelServices.#SatisfyImportsOnce(System.ComponentModel.Composition.ICompositionService,System.Object)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Hosting.CatalogExportProvider+CatalogChangeProxy.#GetExports(System.ComponentModel.Composition.Primitives.ImportDefinition)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Hosting.CatalogExportProvider.#SourceProvider")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Primitives.ComposablePartCatalog.#GetExports(System.ComponentModel.Composition.Primitives.ImportDefinition)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Primitives.ComposablePartException.#GetObjectData(System.Runtime.Serialization.SerializationInfo,System.Runtime.Serialization.StreamingContext)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Hosting.ComposablePartExportProvider.#Compose(System.ComponentModel.Composition.Hosting.CompositionBatch)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Hosting.CompositionContainer.#ReleaseExports(System.Collections.Generic.IEnumerable`1<System.ComponentModel.Composition.Primitives.Export>)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Hosting.CompositionContainer.#ReleaseExports`2(System.Collections.Generic.IEnumerable`1<System.Lazy`2<!!0,!!1>>)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Hosting.CompositionContainer.#ReleaseExports`1(System.Collections.Generic.IEnumerable`1<System.Lazy`1<!!0>>)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.CompositionError.#.ctor(System.Runtime.Serialization.SerializationInfo,System.Runtime.Serialization.StreamingContext)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.CompositionError.#GetObjectData(System.Runtime.Serialization.SerializationInfo,System.Runtime.Serialization.StreamingContext)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.CompositionException.#GetObjectData(System.Runtime.Serialization.SerializationInfo,System.Runtime.Serialization.StreamingContext)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Primitives.ContractBasedImportDefinition.#IsConstraintSatisfiedBy(System.ComponentModel.Composition.Primitives.ExportDefinition)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Hosting.ExportProvider.#GetExports(System.ComponentModel.Composition.Primitives.ImportDefinition,System.ComponentModel.Composition.Hosting.AtomicComposition)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Hosting.ExportProvider.#OnExportsChanged(System.ComponentModel.Composition.Hosting.ExportsChangeEventArgs)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Hosting.ExportProvider.#OnExportsChanging(System.ComponentModel.Composition.Hosting.ExportsChangeEventArgs)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Hosting.ImportEngine.#.ctor(System.ComponentModel.Composition.Hosting.ExportProvider,System.Boolean)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.ReflectionModel.LazyMemberInfo.#.ctor(System.Reflection.MemberInfo)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.ReflectionModel.ReflectionModelServices.#GetExportingMember(System.ComponentModel.Composition.Primitives.ExportDefinition)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.ReflectionModel.ReflectionModelServices.#GetImportingMember(System.ComponentModel.Composition.Primitives.ImportDefinition)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.ReflectionModel.ReflectionModelServices.#GetImportingParameter(System.ComponentModel.Composition.Primitives.ImportDefinition)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.ReflectionModel.ReflectionModelServices.#GetPartType(System.ComponentModel.Composition.Primitives.ComposablePartDefinition)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.ReflectionModel.ReflectionModelServices.#IsDisposalRequired(System.ComponentModel.Composition.Primitives.ComposablePartDefinition)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.ReflectionModel.ReflectionModelServices.#IsImportingParameter(System.ComponentModel.Composition.Primitives.ImportDefinition)")]
+[module: SuppressMessage("Microsoft.Design", "CA1062:Validate arguments of public methods", MessageId = "0", Scope = "member", Target = "System.ComponentModel.Composition.Hosting.TypeCatalog.#GetExports(System.ComponentModel.Composition.Primitives.ImportDefinition)")]
+
+
+[module: SuppressMessage("Microsoft.Design", "CA1032:ImplementStandardExceptionConstructors", Scope = "type", Target = "System.ComponentModel.Composition.ChangeRejectedException")]
+[module: SuppressMessage("Microsoft.Usage", "CA2240:ImplementISerializableCorrectly", Scope = "type", Target = "System.ComponentModel.Composition.CompositionException")]
+[module: SuppressMessage("Microsoft.Design", "CA1032:ImplementStandardExceptionConstructors", Scope = "type", Target = "System.ComponentModel.Composition.CompositionException")]
+[module: SuppressMessage("Microsoft.Maintainability", "CA1506:AvoidExcessiveClassCoupling", Scope = "member", Target = "System.ComponentModel.Composition.MetadataViewGenerator.#GenerateInterfaceViewProxyType(System.Type)")]
+
+
+
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/AttributedModel/AttributedExportDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/AttributedModel/AttributedExportDefinition.cs
new file mode 100644
index 00000000000..022fa16c571
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/AttributedModel/AttributedExportDefinition.cs
@@ -0,0 +1,75 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.ComponentModel.Composition.AttributedModel;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Globalization;
+using System.Linq;
+using System.Reflection;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.AttributedModel
+{
+    internal class AttributedExportDefinition : ExportDefinition
+    {
+        private readonly AttributedPartCreationInfo _partCreationInfo;
+        private readonly MemberInfo _member;
+        private readonly ExportAttribute _exportAttribute;
+        private readonly Type _typeIdentityType;
+
+        private IDictionary<string, object> _metadata;
+
+        public AttributedExportDefinition(AttributedPartCreationInfo partCreationInfo, MemberInfo member, ExportAttribute exportAttribute, Type typeIdentityType, string contractName)
+            : base(contractName, (IDictionary<string, object>)null)
+        {
+            Assumes.NotNull(partCreationInfo);
+            Assumes.NotNull(member);
+            Assumes.NotNull(exportAttribute);
+
+            this._partCreationInfo = partCreationInfo;
+            this._member = member;
+            this._exportAttribute = exportAttribute;
+            this._typeIdentityType = typeIdentityType;
+        }
+
+        public override IDictionary<string, object> Metadata
+        {
+            get
+            {
+                if (this._metadata == null)
+                {
+                    IDictionary<string, object> metadata;
+                    this._member.TryExportMetadataForMember(out metadata);
+
+                    string typeIdentity = this._exportAttribute.IsContractNameSameAsTypeIdentity() ? 
+                        this.ContractName : 
+                        this._member.GetTypeIdentityFromExport(this._typeIdentityType);
+
+                    metadata.Add(CompositionConstants.ExportTypeIdentityMetadataName, typeIdentity);
+
+                    var partMetadata = this._partCreationInfo.GetMetadata();
+                    if (partMetadata != null && partMetadata.ContainsKey(CompositionConstants.PartCreationPolicyMetadataName))
+                    {
+                        metadata.Add(CompositionConstants.PartCreationPolicyMetadataName, partMetadata[CompositionConstants.PartCreationPolicyMetadataName]);
+                    }
+
+                    if ((this._typeIdentityType != null) && (this._member.MemberType != MemberTypes.Method) && this._typeIdentityType.ContainsGenericParameters)
+                    {
+                        metadata.Add(CompositionConstants.GenericExportParametersOrderMetadataName, GenericServices.GetGenericParametersOrder(this._typeIdentityType));
+                    }
+
+                    this._metadata = metadata;
+                }
+                return this._metadata;
+            }
+        }
+    }
+    
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/AttributedModel/AttributedModelDiscovery.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/AttributedModel/AttributedModelDiscovery.cs
new file mode 100644
index 00000000000..011ef6b40f4
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/AttributedModel/AttributedModelDiscovery.cs
@@ -0,0 +1,194 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Diagnostics;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Globalization;
+using System.Reflection;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.AttributedModel
+{
+    internal static class AttributedModelDiscovery
+    {
+        public static ComposablePartDefinition CreatePartDefinitionIfDiscoverable(Type type, ICompositionElement origin)
+        {
+            AttributedPartCreationInfo creationInfo = new AttributedPartCreationInfo(type, null, false, origin);
+            if (!creationInfo.IsPartDiscoverable())
+            {
+                return null;
+            }
+
+            return new ReflectionComposablePartDefinition(creationInfo);
+        }
+
+        public static ReflectionComposablePartDefinition CreatePartDefinition(Type type, PartCreationPolicyAttribute partCreationPolicy, bool ignoreConstructorImports, ICompositionElement origin)
+        {
+            Assumes.NotNull(type);
+
+            AttributedPartCreationInfo creationInfo = new AttributedPartCreationInfo(type, partCreationPolicy, ignoreConstructorImports, origin);
+
+            return new ReflectionComposablePartDefinition(creationInfo);
+        }
+
+        public static ReflectionComposablePart CreatePart(object attributedPart)
+        {
+            Assumes.NotNull(attributedPart);
+
+            // If given an instance then we want to pass the default composition options because we treat it as a shared part
+            // TODO: ICompositionElement Give this def an origin indicating that it was added directly to the ComposablePartExportProvider.
+
+            ReflectionComposablePartDefinition definition = AttributedModelDiscovery.CreatePartDefinition(attributedPart.GetType(), PartCreationPolicyAttribute.Shared, true, (ICompositionElement)null);
+
+            return new ReflectionComposablePart(definition, attributedPart);
+        }
+
+#if FEATURE_REFLECTIONCONTEXT
+        public static ReflectionComposablePart CreatePart(object attributedPart, ReflectionContext reflectionContext)
+        {
+            Assumes.NotNull(attributedPart);
+            Assumes.NotNull(reflectionContext);
+
+            // If given an instance then we want to pass the default composition options because we treat it as a shared part
+            // TODO: ICompositionElement Give this def an origin indicating that it was added directly to the ComposablePartExportProvider.
+
+            var mappedType = reflectionContext.MapType(IntrospectionExtensions.GetTypeInfo(attributedPart.GetType()));
+            if (mappedType.Assembly.ReflectionOnly)
+            {
+                throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, Strings.Argument_ReflectionContextReturnsReflectionOnlyType, "reflectionContext"), "reflectionContext");
+            }
+
+            ReflectionComposablePartDefinition definition = AttributedModelDiscovery.CreatePartDefinition(mappedType, PartCreationPolicyAttribute.Shared, true, (ICompositionElement)null);
+
+            return CreatePart(definition, attributedPart);
+        }
+#endif //FEATURE_REFLECTIONCONTEXT
+
+        public static ReflectionComposablePart CreatePart(ComposablePartDefinition partDefinition, object attributedPart)
+        {
+            Assumes.NotNull(partDefinition);
+            Assumes.NotNull(attributedPart);
+
+            return new ReflectionComposablePart((ReflectionComposablePartDefinition)partDefinition, attributedPart);
+        }
+
+        public static ReflectionParameterImportDefinition CreateParameterImportDefinition(ParameterInfo parameter, ICompositionElement origin)
+        {
+            Requires.NotNull(parameter, "parameter");
+
+            ReflectionParameter reflectionParameter = parameter.ToReflectionParameter();
+            IAttributedImport attributedImport = AttributedModelDiscovery.GetAttributedImport(reflectionParameter, parameter);
+            ImportType importType = new ImportType(reflectionParameter.ReturnType, attributedImport.Cardinality);
+
+            if (importType.IsPartCreator)
+            {
+                return new PartCreatorParameterImportDefinition(
+                    new Lazy<ParameterInfo>(() => parameter),
+                    origin,
+                    new ContractBasedImportDefinition(
+                        attributedImport.GetContractNameFromImport(importType),
+                        attributedImport.GetTypeIdentityFromImport(importType),
+                        CompositionServices.GetRequiredMetadata(importType.MetadataViewType),
+                        attributedImport.Cardinality,
+                        false,
+                        true,
+                        (attributedImport.RequiredCreationPolicy != CreationPolicy.NewScope) ? CreationPolicy.NonShared : CreationPolicy.NewScope,
+                        CompositionServices.GetImportMetadata(importType, attributedImport)));
+            }
+            else
+            {
+                // A Standard import is not allowed to be marked as requiring NewScope at this time.
+                if(attributedImport.RequiredCreationPolicy == CreationPolicy.NewScope)
+                {
+                    throw new ComposablePartException(
+                        String.Format(CultureInfo.CurrentCulture,
+                            Strings.InvalidPartCreationPolicyOnImport,
+                            attributedImport.RequiredCreationPolicy),
+                        origin);
+                }
+                return new ReflectionParameterImportDefinition(
+                    new Lazy<ParameterInfo>(() => parameter),
+                    attributedImport.GetContractNameFromImport(importType),
+                    attributedImport.GetTypeIdentityFromImport(importType),
+                    CompositionServices.GetRequiredMetadata(importType.MetadataViewType),
+                    attributedImport.Cardinality,
+                    attributedImport.RequiredCreationPolicy,
+                    CompositionServices.GetImportMetadata(importType, attributedImport),
+                    origin);
+            }
+        }
+
+        public static ReflectionMemberImportDefinition CreateMemberImportDefinition(MemberInfo member, ICompositionElement origin)
+        {
+            Requires.NotNull(member, "member");
+
+            ReflectionWritableMember reflectionMember = member.ToReflectionWritableMember();
+            IAttributedImport attributedImport = AttributedModelDiscovery.GetAttributedImport(reflectionMember, member);
+            ImportType importType = new ImportType(reflectionMember.ReturnType, attributedImport.Cardinality);
+
+            if (importType.IsPartCreator)
+            {
+                return new PartCreatorMemberImportDefinition(
+                    new LazyMemberInfo(member),
+                    origin,
+                    new ContractBasedImportDefinition(
+                        attributedImport.GetContractNameFromImport(importType),
+                        attributedImport.GetTypeIdentityFromImport(importType),
+                        CompositionServices.GetRequiredMetadata(importType.MetadataViewType),
+                        attributedImport.Cardinality,
+                        attributedImport.AllowRecomposition,
+                        false,
+                        (attributedImport.RequiredCreationPolicy != CreationPolicy.NewScope) ? CreationPolicy.NonShared : CreationPolicy.NewScope,
+                        CompositionServices.GetImportMetadata(importType, attributedImport)));
+            }
+            else
+            {
+                // A Standard parameter import is not allowed to be marked as requiring NewScope at this time.
+                if(attributedImport.RequiredCreationPolicy == CreationPolicy.NewScope)
+                {
+                    throw new ComposablePartException(
+                        String.Format(CultureInfo.CurrentCulture,
+                            Strings.InvalidPartCreationPolicyOnImport,
+                            attributedImport.RequiredCreationPolicy),
+                        origin);
+                }
+
+                //Does this Import re-export the value if so, make it a rpe-requisite
+                bool isPrerequisite = member.GetAttributes<ExportAttribute>().Length > 0;
+                return new ReflectionMemberImportDefinition(
+                    new LazyMemberInfo(member),
+                    attributedImport.GetContractNameFromImport(importType),
+                    attributedImport.GetTypeIdentityFromImport(importType),
+                    CompositionServices.GetRequiredMetadata(importType.MetadataViewType),
+                    attributedImport.Cardinality,
+                    attributedImport.AllowRecomposition,
+                    isPrerequisite,
+                    attributedImport.RequiredCreationPolicy,
+                    CompositionServices.GetImportMetadata(importType, attributedImport),
+                    origin);
+            }
+        }
+
+        private static IAttributedImport GetAttributedImport(ReflectionItem item, ICustomAttributeProvider attributeProvider)
+        {
+            IAttributedImport[] imports = attributeProvider.GetAttributes<IAttributedImport>(false);
+
+            // For constructor parameters they may not have an ImportAttribute
+            if (imports.Length == 0)
+            {
+                return new ImportAttribute();
+            }
+
+            if (imports.Length > 1)
+            {
+                CompositionTrace.MemberMarkedWithMultipleImportAndImportMany(item);
+            }
+
+            // Regardless of how many imports, always return the first one
+            return imports[0];
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/AttributedModel/AttributedPartCreationInfo.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/AttributedModel/AttributedPartCreationInfo.cs
new file mode 100644
index 00000000000..c97dca8c612
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/AttributedModel/AttributedPartCreationInfo.cs
@@ -0,0 +1,511 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Diagnostics;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Globalization;
+using System.Linq;
+using System.Reflection;
+using System.Threading;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.AttributedModel
+{
+    internal class AttributedPartCreationInfo : IReflectionPartCreationInfo
+    {
+        private readonly Type _type;
+        private readonly bool _ignoreConstructorImports = false;
+        private readonly ICompositionElement _origin;
+        private PartCreationPolicyAttribute _partCreationPolicy = null;
+        private ConstructorInfo _constructor;
+        private IEnumerable<ExportDefinition> _exports;
+        private IEnumerable<ImportDefinition> _imports;
+        private HashSet<string> _contractNamesOnNonInterfaces;
+
+        public AttributedPartCreationInfo(Type type, PartCreationPolicyAttribute partCreationPolicy, bool ignoreConstructorImports, ICompositionElement origin)
+        {
+            Assumes.NotNull(type);
+            
+            this._type = type;
+            this._ignoreConstructorImports = ignoreConstructorImports;
+            this._partCreationPolicy = partCreationPolicy;
+            this._origin = origin;
+        }
+
+        public Type GetPartType()
+        {
+            return this._type;
+        }
+
+        public Lazy<Type> GetLazyPartType()
+        {
+            return new Lazy<Type>(this.GetPartType, LazyThreadSafetyMode.PublicationOnly);
+        }
+
+        public ConstructorInfo GetConstructor()
+        {
+            if (this._constructor == null && !this._ignoreConstructorImports)
+            {
+                this._constructor = SelectPartConstructor(this._type);
+            }
+            return this._constructor;
+        }
+
+        public IDictionary<string, object> GetMetadata()
+        {
+            return this._type.GetPartMetadataForType(this.CreationPolicy);
+        }
+
+        public IEnumerable<ExportDefinition> GetExports()
+        {
+            DiscoverExportsAndImports();
+            return this._exports;
+        }
+
+        public IEnumerable<ImportDefinition> GetImports()
+        {
+            DiscoverExportsAndImports();
+            return this._imports;
+        }
+
+        public bool IsDisposalRequired
+        {
+            get
+            {
+                return typeof(IDisposable).IsAssignableFrom(this.GetPartType());
+            }
+        }
+
+        public bool IsPartDiscoverable()
+        {
+            // The part should not be marked with the "NonDiscoverable"
+            if (this._type.IsAttributeDefined<PartNotDiscoverableAttribute>())
+            {
+                CompositionTrace.DefinitionMarkedWithPartNotDiscoverableAttribute(this._type);
+                return false;
+            }
+
+            // The part should have exports
+            if (!HasExports())
+            {
+                CompositionTrace.DefinitionContainsNoExports(this._type);
+                return false;
+            }
+
+            // If the part is generic, all exports should have the same number of generic parameters
+            // (otherwise we have no way to specialize the part based on an export)
+            if (!AllExportsHaveMatchingArity())
+            {
+                // The function has already reported all violations via tracing
+                return false;
+            }
+
+            return true;
+        }
+
+        private bool HasExports()
+        {
+            return GetExportMembers(this._type).Any() ||
+                   GetInheritedExports(this._type).Any();
+        }
+
+        private bool AllExportsHaveMatchingArity()
+        {
+            bool isArityMatched = true;
+            if (this._type.ContainsGenericParameters)
+            {
+                int partGenericArity = this._type.GetPureGenericArity();
+
+                // each member should have the same arity
+                foreach (MemberInfo member in GetExportMembers(this._type).Concat(GetInheritedExports(this._type)))
+                {
+                    if (member.MemberType == MemberTypes.Method)
+                    {
+                        // open generics are unsupported on methods
+                        if (((MethodInfo)member).ContainsGenericParameters)
+                        {
+                            isArityMatched = false;
+                            CompositionTrace.DefinitionMismatchedExportArity(this._type, member);
+                            continue;
+                        }
+                    }
+
+                    if (member.GetDefaultTypeFromMember().GetPureGenericArity() != partGenericArity)
+                    {
+                        isArityMatched = false;
+                        CompositionTrace.DefinitionMismatchedExportArity(this._type, member);
+                    }
+                }
+            }
+
+            return isArityMatched;
+        }
+
+
+        string ICompositionElement.DisplayName
+        {
+            get { return this.GetDisplayName(); }
+        }
+
+        ICompositionElement ICompositionElement.Origin
+        {
+            get { return this._origin; }
+        }
+
+        public override string ToString()
+        {
+            return GetDisplayName();
+        }
+
+        private string GetDisplayName()
+        {
+            return this.GetPartType().GetDisplayName();
+        }
+
+        private CreationPolicy CreationPolicy
+        {
+            get
+            {
+                if (this._partCreationPolicy == null)
+                {
+                    this._partCreationPolicy = this._type.GetFirstAttribute<PartCreationPolicyAttribute>() ?? PartCreationPolicyAttribute.Default;
+                }
+
+                // A Part is not allowed to be marked as NewScope at this time.
+                if(this._partCreationPolicy.CreationPolicy == CreationPolicy.NewScope)
+                {
+                    throw new ComposablePartException(
+                        String.Format(CultureInfo.CurrentCulture,
+                            Strings.InvalidPartCreationPolicyOnPart,
+                            this._partCreationPolicy.CreationPolicy),
+                        this._origin);
+                }
+
+                return this._partCreationPolicy.CreationPolicy;
+            }
+        }
+
+        private static ConstructorInfo SelectPartConstructor(Type type)
+        {
+            Assumes.NotNull(type);
+
+            if (type.IsAbstract)
+            {
+                return null;
+            }
+
+            // Only deal with non-static constructors
+            BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance;
+
+            ConstructorInfo[] constructors = type.GetConstructors(flags);
+
+            // Should likely only happen for static or abstract types
+            if (constructors.Length == 0)
+            {
+                return null;
+            }
+
+            // Optimize single default constructor.
+            if (constructors.Length == 1 && constructors[0].GetParameters().Length == 0)
+            {
+                return constructors[0];
+            }
+
+            // Select the marked constructor if there is exactly one marked
+            ConstructorInfo importingConstructor = null;
+            ConstructorInfo defaultConstructor = null;
+            foreach (ConstructorInfo constructor in constructors)
+            {
+                // an importing constructor found
+                if (constructor.IsAttributeDefined<ImportingConstructorAttribute>())
+                {
+                    if (importingConstructor != null)
+                    {
+                        // more that one importing constructor - return null ot error out on creation
+                        return null;
+                    }
+                    else
+                    {
+                        importingConstructor = constructor;
+                    }
+                }
+                // otherwise if we havent seen the default constructor yet, check if this one is it
+                else if (defaultConstructor == null)
+                {
+                    if (constructor.GetParameters().Length == 0)
+                    {
+                        defaultConstructor = constructor;
+                    }
+                }
+            }
+
+            return importingConstructor ?? defaultConstructor;
+        }
+
+        private void DiscoverExportsAndImports()
+        {
+            // NOTE : in most cases both of these will be null or not null at the same time
+            // the only situation when that is not the case is when there was a failure during the previous discovery
+            // and one of them ended up not being set. In that case we will force the discovery again so that the same exception is thrown.
+            if ((this._exports != null) && (this._imports != null))
+            {
+                return;
+            }
+
+            this._exports = GetExportDefinitions();
+            this._imports = GetImportDefinitions();
+        }
+
+        private IEnumerable<ExportDefinition> GetExportDefinitions()
+        {
+            List<ExportDefinition> exports = new List<ExportDefinition>();
+
+            this._contractNamesOnNonInterfaces = new HashSet<string>();
+
+            // GetExportMembers should only contain the type itself along with the members declared on it, 
+            // it should not contain any base types, members on base types or interfaces on the type.
+            foreach (MemberInfo member in GetExportMembers(this._type))
+            {
+                foreach (ExportAttribute exportAttribute in member.GetAttributes<ExportAttribute>())
+                {
+                    var attributedExportDefinition = this.CreateExportDefinition(member, exportAttribute);
+
+                    if (exportAttribute.GetType() == CompositionServices.InheritedExportAttributeType)
+                    {
+                        // Any InheritedExports on the type itself are contributed during this pass 
+                        // and we need to do the book keeping for those.
+                        if (!this._contractNamesOnNonInterfaces.Contains(attributedExportDefinition.ContractName))
+                        {
+                            exports.Add(new ReflectionMemberExportDefinition(member.ToLazyMember(), attributedExportDefinition, this));
+                            this._contractNamesOnNonInterfaces.Add(attributedExportDefinition.ContractName);
+                        }
+                    }
+                    else
+                    {
+                        exports.Add(new ReflectionMemberExportDefinition(member.ToLazyMember(), attributedExportDefinition, this));
+                    }
+                }
+            }
+
+            // GetInheritedExports should only contain InheritedExports on base types or interfaces.
+            // The order of types returned here is important because it is used as a 
+            // priority list of which InhertedExport to choose if multiple exists with 
+            // the same contract name. Therefore ensure that we always return the types
+            // in the hiearchy from most derived to the lowest base type, followed
+            // by all the interfaces that this type implements.
+            foreach (Type type in GetInheritedExports(this._type))
+            {
+                foreach (InheritedExportAttribute exportAttribute in type.GetAttributes<InheritedExportAttribute>())
+                {
+                    var attributedExportDefinition = this.CreateExportDefinition(type, exportAttribute);
+
+                    if (!this._contractNamesOnNonInterfaces.Contains(attributedExportDefinition.ContractName))
+                    {
+                        exports.Add(new ReflectionMemberExportDefinition(type.ToLazyMember(), attributedExportDefinition, this));
+
+                        if (!type.IsInterface)
+                        {
+                            this._contractNamesOnNonInterfaces.Add(attributedExportDefinition.ContractName);
+                        }
+                    }
+                }
+            }
+
+            this._contractNamesOnNonInterfaces = null; // No need to hold this state around any longer
+
+            return exports;
+        }
+
+        private AttributedExportDefinition CreateExportDefinition(MemberInfo member, ExportAttribute exportAttribute)
+        {
+            string contractName = null;
+            Type typeIdentityType = null;
+            member.GetContractInfoFromExport(exportAttribute, out typeIdentityType, out contractName);
+
+            return new AttributedExportDefinition(this, member, exportAttribute, typeIdentityType, contractName);
+        }
+
+        private IEnumerable<MemberInfo> GetExportMembers(Type type)
+        {
+            BindingFlags flags = BindingFlags.DeclaredOnly | BindingFlags.Public |
+                BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;
+
+            // If the type is abstract only find local static exports
+            if (type.IsAbstract)
+            {
+                flags &= ~BindingFlags.Instance;
+            }
+            else if (IsExport(type))
+            {
+                yield return type;
+            }
+
+            // Walk the fields 
+            foreach (var member in type.GetFields(flags))
+            {
+                if (IsExport(member))
+                {
+                    yield return member;
+                }
+            }
+
+            // Walk the properties 
+            foreach (var member in type.GetProperties(flags))
+            {
+                if (IsExport(member))
+                {
+                    yield return member;
+                }
+            }
+
+            // Walk the methods 
+            foreach (var member in type.GetMethods(flags))
+            {
+                if (IsExport(member))
+                {
+                    yield return member;
+                }
+            }
+        }
+
+        private IEnumerable<Type> GetInheritedExports(Type type)
+        {
+            // If the type is abstract we aren't interested in type level exports
+            if (type.IsAbstract)
+            {
+                yield break;
+            }
+
+            // The order of types returned here is important because it is used as a 
+            // priority list of which InhertedExport to choose if multiple exists with 
+            // the same contract name. Therefore ensure that we always return the types
+            // in the hiearchy from most derived to the lowest base type, followed
+            // by all the interfaces that this type implements.
+
+            Type currentType = type.BaseType;
+
+            if (currentType == null)
+            {
+                yield break;
+            }
+            
+            // Stopping at object instead of null to help with performance. It is a noticable performance
+            // gain (~5%) if we don't have to try and pull the attributes we know don't exist on object.
+            // We also need the null check in case we're passed a type that doesn't live in the runtime context.
+            while (currentType != null && currentType.UnderlyingSystemType != CompositionServices.ObjectType)
+            {
+                if (IsInheritedExport(currentType))
+                {
+                    yield return currentType;
+                }
+                currentType = currentType.BaseType;
+            }
+
+            foreach (Type iface in type.GetInterfaces())
+            {
+                if (IsInheritedExport(iface))
+                {
+                    yield return iface;
+                }
+            }
+        }
+
+        private static bool IsExport(ICustomAttributeProvider attributeProvider)
+        {
+            return attributeProvider.IsAttributeDefined<ExportAttribute>(false);
+        }
+
+        private static bool IsInheritedExport(ICustomAttributeProvider attributedProvider)
+        {
+            return attributedProvider.IsAttributeDefined<InheritedExportAttribute>(false);
+        }
+
+        private IEnumerable<ImportDefinition> GetImportDefinitions()
+        {
+            List<ImportDefinition> imports = new List<ImportDefinition>();
+
+            foreach (MemberInfo member in GetImportMembers(this._type))
+            {
+                ReflectionMemberImportDefinition importDefinition = AttributedModelDiscovery.CreateMemberImportDefinition(member, this);
+                imports.Add(importDefinition);
+            }
+
+            var constructor = this.GetConstructor();
+
+            if (constructor != null)
+            {
+                foreach (ParameterInfo parameter in constructor.GetParameters())
+                {
+                    ReflectionParameterImportDefinition importDefinition = AttributedModelDiscovery.CreateParameterImportDefinition(parameter, this);
+                    imports.Add(importDefinition);
+                }
+            }
+
+            return imports;
+        }
+
+        private IEnumerable<MemberInfo> GetImportMembers(Type type)
+        {
+            if (type.IsAbstract)
+            {
+                yield break;
+            }
+
+            foreach (MemberInfo member in GetDeclaredOnlyImportMembers(type))
+            {
+                yield return member;
+            }
+
+            // Walk up the type chain until you hit object.
+            if (type.BaseType != null)
+            {
+                Type baseType = type.BaseType;
+
+                // Stopping at object instead of null to help with performance. It is a noticable performance
+                // gain (~5%) if we don't have to try and pull the attributes we know don't exist on object.
+                // We also need the null check in case we're passed a type that doesn't live in the runtime context.
+                while (baseType != null && baseType.UnderlyingSystemType != CompositionServices.ObjectType)
+                {
+                    foreach (MemberInfo member in GetDeclaredOnlyImportMembers(baseType))
+                    {
+                        yield return member;
+                    }
+                    baseType = baseType.BaseType;
+                }
+            }
+        }
+
+        private IEnumerable<MemberInfo> GetDeclaredOnlyImportMembers(Type type)
+        {
+            BindingFlags flags = BindingFlags.DeclaredOnly | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance;
+
+            // Walk the fields 
+            foreach (var member in type.GetFields(flags))
+            {
+                if (IsImport(member))
+                {
+                    yield return member;
+                }
+            }
+
+            // Walk the properties 
+            foreach (var member in type.GetProperties(flags))
+            {
+                if (IsImport(member))
+                {
+                    yield return member;
+                }
+            }
+        }
+
+        private static bool IsImport(ICustomAttributeProvider attributeProvider)
+        {
+            return attributeProvider.IsAttributeDefined<IAttributedImport>(false);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/AttributedModelServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/AttributedModelServices.cs
new file mode 100644
index 00000000000..86cea512726
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/AttributedModelServices.cs
@@ -0,0 +1,330 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.AttributedModel;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Linq;
+using System.Reflection;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition
+{
+    public static class AttributedModelServices
+    {
+        [SuppressMessage("Microsoft.Design", "CA1004")]
+        public static TMetadataView GetMetadataView<TMetadataView>(IDictionary<string, object> metadata)
+        {
+            Requires.NotNull(metadata, "metadata");
+            Contract.Ensures(Contract.Result<TMetadataView>() != null);
+
+            return MetadataViewProvider.GetMetadataView<TMetadataView>(metadata);
+        }
+
+        public static ComposablePart CreatePart(object attributedPart)
+        {
+            Requires.NotNull(attributedPart, "attributedPart");
+            Contract.Ensures(Contract.Result<ComposablePart>() != null);
+
+            return AttributedModelDiscovery.CreatePart(attributedPart);
+        }
+
+#if FEATURE_REFLECTIONCONTEXT
+        public static ComposablePart CreatePart(object attributedPart, ReflectionContext reflectionContext)
+        {
+            Requires.NotNull(attributedPart, "attributedPart");
+            Requires.NotNull(reflectionContext, "reflectionContext");
+            Contract.Ensures(Contract.Result<ComposablePart>() != null);
+
+            return AttributedModelDiscovery.CreatePart(attributedPart, reflectionContext);
+        }
+#endif //FEATURE_REFLECTIONCONTEXT
+
+        public static ComposablePart CreatePart(ComposablePartDefinition partDefinition, object attributedPart)
+        {
+            Requires.NotNull(partDefinition, "partDefinition");
+            Requires.NotNull(attributedPart, "attributedPart");
+            Contract.Ensures(Contract.Result<ComposablePart>() != null);
+
+            var reflectionComposablePartDefinition = partDefinition as ReflectionComposablePartDefinition;
+            if(reflectionComposablePartDefinition == null)
+            {
+                throw ExceptionBuilder.CreateReflectionModelInvalidPartDefinition("partDefinition", partDefinition.GetType());
+            }
+
+            return AttributedModelDiscovery.CreatePart(reflectionComposablePartDefinition, attributedPart);
+        }
+
+        public static ComposablePartDefinition CreatePartDefinition(Type type, ICompositionElement origin)
+        {
+            Requires.NotNull(type, "type");
+            Contract.Ensures(Contract.Result<ComposablePartDefinition>() != null);
+
+            return AttributedModelServices.CreatePartDefinition(type, origin, false);
+        }
+
+        public static ComposablePartDefinition CreatePartDefinition(Type type, ICompositionElement origin, bool ensureIsDiscoverable)
+        {
+            Requires.NotNull(type, "type");
+            if (ensureIsDiscoverable)
+            {
+                return AttributedModelDiscovery.CreatePartDefinitionIfDiscoverable(type, origin);
+            }
+            else
+            {
+                return AttributedModelDiscovery.CreatePartDefinition(type, null, false, origin);
+            }
+        }
+
+        public static string GetTypeIdentity(Type type)
+        {
+            Requires.NotNull(type, "type");
+            Contract.Ensures(!string.IsNullOrEmpty(Contract.Result<string>()));
+
+            return ContractNameServices.GetTypeIdentity(type);
+        }
+
+        public static string GetTypeIdentity(MethodInfo method)
+        {
+            Requires.NotNull(method, "method");
+            Contract.Ensures(!string.IsNullOrEmpty(Contract.Result<string>()));
+
+            return ContractNameServices.GetTypeIdentityFromMethod(method);
+        }
+
+        public static string GetContractName(Type type)
+        {
+            Requires.NotNull(type, "type");
+            Contract.Ensures(!string.IsNullOrEmpty(Contract.Result<string>()));
+
+            return AttributedModelServices.GetTypeIdentity(type);
+        }
+
+        public static ComposablePart AddExportedValue<T>(this CompositionBatch batch, T exportedValue)
+        {
+            Requires.NotNull(batch, "batch");
+            Contract.Ensures(Contract.Result<ComposablePart>() != null);
+
+            string contractName = AttributedModelServices.GetContractName(typeof(T));
+
+            return batch.AddExportedValue<T>(contractName, exportedValue);
+        }
+
+        public static void ComposeExportedValue<T>(this CompositionContainer container, T exportedValue)
+        {
+            Requires.NotNull(container, "container");
+
+            CompositionBatch batch = new CompositionBatch();
+            batch.AddExportedValue<T>(exportedValue);
+            container.Compose(batch);
+        }
+
+        public static ComposablePart AddExportedValue<T>(this CompositionBatch batch, string contractName, T exportedValue)
+        {
+            Requires.NotNull(batch, "batch");
+            Contract.Ensures(Contract.Result<ComposablePart>() != null);
+
+            string typeIdentity = AttributedModelServices.GetTypeIdentity(typeof(T));
+
+            IDictionary<string, object> metadata = new Dictionary<string, object>();
+            metadata.Add(CompositionConstants.ExportTypeIdentityMetadataName, typeIdentity);
+
+            return batch.AddExport(new Export(contractName, metadata, () => exportedValue));
+        }
+
+        public static void ComposeExportedValue<T>(this CompositionContainer container, string contractName, T exportedValue)
+        {
+            Requires.NotNull(container, "container");
+
+            CompositionBatch batch = new CompositionBatch();
+            batch.AddExportedValue<T>(contractName, exportedValue);
+            container.Compose(batch);
+        }
+
+        public static ComposablePart AddPart(this CompositionBatch batch, object attributedPart)
+        {
+            Requires.NotNull(batch, "batch");
+            Requires.NotNull(attributedPart, "attributedPart");
+            Contract.Ensures(Contract.Result<ComposablePart>() != null);
+
+            ComposablePart part = AttributedModelServices.CreatePart(attributedPart);
+
+            batch.AddPart(part);
+
+            return part;
+        }
+
+        public static void ComposeParts(this CompositionContainer container, params object[] attributedParts)
+        {
+            Requires.NotNull(container, "container");
+            Requires.NotNullOrNullElements(attributedParts, "attributedParts");
+
+            CompositionBatch batch = new CompositionBatch(
+                attributedParts.Select(attributedPart => AttributedModelServices.CreatePart(attributedPart)).ToArray(),
+                Enumerable.Empty<ComposablePart>());
+
+            container.Compose(batch);
+        }
+
+        /// <summary>
+        ///     Satisfies the imports of the specified attributed object exactly once and they will not
+        ///     ever be recomposed.
+        /// </summary>
+        /// <param name="part">
+        ///     The attributed object to set the imports.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="compositionService"/> or <paramref name="attributedPart"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ICompositionService"/> has been disposed of.
+        /// </exception>
+        public static ComposablePart SatisfyImportsOnce(this ICompositionService compositionService, object attributedPart)
+        {
+            Requires.NotNull(compositionService, "compositionService");
+            Requires.NotNull(attributedPart, "attributedPart");
+            Contract.Ensures(Contract.Result<ComposablePart>() != null);
+
+            ComposablePart part = AttributedModelServices.CreatePart(attributedPart);
+            compositionService.SatisfyImportsOnce(part);
+
+            return part;
+        }
+
+#if FEATURE_REFLECTIONCONTEXT
+        /// <summary>
+        ///     Satisfies the imports of the specified attributed object exactly once and they will not
+        ///     ever be recomposed.
+        /// </summary>
+        /// <param name="part">
+        ///     The attributed object to set the imports.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="compositionService"/> or <paramref name="attributedPart"/>  or <paramref name="reflectionContext"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ICompositionService"/> has been disposed of.
+        /// </exception>
+        public static ComposablePart SatisfyImportsOnce(this ICompositionService compositionService, object attributedPart, ReflectionContext reflectionContext)
+        {
+            Requires.NotNull(compositionService, "compositionService");
+            Requires.NotNull(attributedPart, "attributedPart");
+            Requires.NotNull(reflectionContext, "reflectionContext");
+            Contract.Ensures(Contract.Result<ComposablePart>() != null);
+
+            ComposablePart part = AttributedModelServices.CreatePart(attributedPart, reflectionContext);
+            compositionService.SatisfyImportsOnce(part);
+
+            return part;
+        }
+#endif //FEATURE_REFLECTIONCONTEXT
+
+        /// <summary>
+        /// Determines whether the specified part exports the specified contract.
+        /// </summary>
+        /// <param name="part">The part.</param>
+        /// <param name="contractType">Type of the contract.</param>
+        /// <returns>
+        /// 	<c>true</c> if the specified part exports the specified contract; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool Exports(this ComposablePartDefinition part, Type contractType)
+        {
+            Requires.NotNull(part, "part");
+            Requires.NotNull(contractType, "contractType");
+
+            return part.Exports(AttributedModelServices.GetContractName(contractType));
+        }
+
+        /// <summary>
+        /// Determines whether the specified part exports the specified contract.
+        /// </summary>
+        /// <typeparam name="T">Type of the contract.</typeparam>
+        /// <param name="part">The part.</param>
+        /// <returns>
+        /// 	<c>true</c> if the specified part exports the specified contract; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool Exports<T>(this ComposablePartDefinition part)
+        {
+            Requires.NotNull(part, "part");
+
+            return part.Exports(typeof(T));
+        }
+
+        /// <summary>
+        /// Determines whether the specified part imports the specified contract.
+        /// </summary>
+        /// <param name="part">The part.</param>
+        /// <param name="contractType">Type of the contract.</param>
+        /// <returns>
+        /// 	<c>true</c> if the specified part imports the specified contract; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool Imports(this ComposablePartDefinition part, Type contractType)
+        {
+            Requires.NotNull(part, "part");
+            Requires.NotNull(contractType, "contractType");
+
+            return part.Imports(AttributedModelServices.GetContractName(contractType));
+        }
+
+        /// <summary>
+        /// Determines whether the specified part imports the specified contract.
+        /// </summary>
+        /// <param name="part">The part.</param>
+        /// <typeparam name="T">Type of the contract.</typeparam>
+        /// <returns>
+        /// 	<c>true</c> if the specified part imports the specified contract; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool Imports<T>(this ComposablePartDefinition part)
+        {
+            Requires.NotNull(part, "part");
+
+            return part.Imports(typeof(T));
+        }
+
+        /// <summary>
+        /// Determines whether the specified part imports the specified contract with the given cardinality.
+        /// </summary>
+        /// <param name="part">The part.</param>
+        /// <param name="contractType">Type of the contract.</param>
+        /// <param name="importCardinality">The import cardinality.</param>
+        /// <returns>
+        /// 	<c>true</c> if the specified part imports the specified contract with the given cardinality; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool Imports(this ComposablePartDefinition part, Type contractType, ImportCardinality importCardinality)
+        {
+            Requires.NotNull(part, "part");
+            Requires.NotNull(contractType, "contractType");
+
+            return part.Imports(AttributedModelServices.GetContractName(contractType), importCardinality);
+        }
+
+        /// <summary>
+        /// Determines whether the specified part imports the specified contract with the given cardinality.
+        /// </summary>
+        /// <param name="part">The part.</param>
+        /// <typeparam name="T">Type of the contract.</typeparam>
+        /// <param name="importCardinality">The import cardinality.</param>
+        /// <returns>
+        /// 	<c>true</c> if the specified part imports the specified contract with the given cardinality; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool Imports<T>(this ComposablePartDefinition part, ImportCardinality importCardinality)
+        {
+            Requires.NotNull(part, "part");
+
+            return part.Imports(typeof(T), importCardinality);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CatalogReflectionContextAttribute.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CatalogReflectionContextAttribute.cs
new file mode 100644
index 00000000000..1a5dfad029b
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CatalogReflectionContextAttribute.cs
@@ -0,0 +1,56 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+
+#if FEATURE_REFLECTIONCONTEXT
+
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Reflection;
+using System.Threading;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Enables the AssemblyCatalog to discover user provided ReflectionContexts.
+    /// </summary>
+    [SuppressMessage("Microsoft.Performance", "CA1813:AvoidUnsealedAttributes")]
+    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = false,Inherited = true)]
+    public class CatalogReflectionContextAttribute : Attribute
+    {
+        Type _reflectionContextType;
+
+        public CatalogReflectionContextAttribute(Type reflectionContextType)
+        {
+            Requires.NotNull(reflectionContextType, "reflectionContextType");
+
+            this._reflectionContextType = reflectionContextType;
+        }
+
+        public ReflectionContext CreateReflectionContext()
+        {
+            Assumes.NotNull<Type>(this._reflectionContextType);
+
+            ReflectionContext reflectionContext = null;
+            try
+            {
+                reflectionContext = (ReflectionContext)Activator.CreateInstance(this._reflectionContextType);
+            }
+            catch (InvalidCastException invalidCastException)
+            {
+                throw new InvalidOperationException(Strings.ReflectionContext_Type_Required, invalidCastException);
+            }
+            catch (MissingMethodException missingMethodException)
+            {
+                throw new MissingMethodException(Strings.ReflectionContext_Requires_DefaultConstructor, missingMethodException);
+            }
+
+            return reflectionContext;
+        }
+    }
+}
+#endif //FEATURE_REFLECTIONCONTEXT
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ChangeRejectedException.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ChangeRejectedException.cs
new file mode 100644
index 00000000000..3f5da5c2225
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ChangeRejectedException.cs
@@ -0,0 +1,69 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Security.Permissions;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     The exception that is thrown when one or more recoverable errors occur during
+    ///     composition which results in those changes being rejected.
+    /// </summary>
+    [Serializable]
+    public class ChangeRejectedException : CompositionException
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ChangeRejectedException"/> class.
+        /// </summary>
+        public ChangeRejectedException()
+            : this((string)null, (Exception)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ChangeRejectedException"/> class.
+        /// </summary>
+        public ChangeRejectedException(string message)
+            : this(message, (Exception)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ChangeRejectedException"/> class.
+        /// </summary>
+        public ChangeRejectedException(string message, Exception innerException)
+            : base(message, innerException, (IEnumerable<CompositionError>)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ChangeRejectedException"/> class.
+        /// </summary>
+        /// <param name="errors">List of errors that occured while applying the changes.</param>
+        public ChangeRejectedException(IEnumerable<CompositionError> errors)
+            : base((string)null, (Exception)null, errors)
+        {
+        }
+
+        /// <summary>
+        ///     Gets a message that describes the exception.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="ChangeRejectedException"/>.
+        /// </value>
+        public override string Message
+        {
+            get
+            {
+                return string.Format(CultureInfo.CurrentCulture, 
+                    Strings.CompositionException_ChangesRejected,
+                    base.Message);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionContractMismatchException.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionContractMismatchException.cs
new file mode 100644
index 00000000000..4d15c1beb3c
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionContractMismatchException.cs
@@ -0,0 +1,90 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Runtime.Serialization;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     The exception that is thrown when the underlying exported value or metadata of an 
+    ///     <see cref="Lazy{T}"/> or <see cref="Lazy{T, TMetadataView}"/> object cannot be 
+    ///     cast to <c>T</c> or <c>TMetadataView</c>, respectively.
+    /// </summary>
+    [Serializable]
+    public class CompositionContractMismatchException : Exception
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionContractMismatchException"/> class.
+        /// </summary>
+        public CompositionContractMismatchException()
+            : this((string)null, (Exception)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionContractMismatchException"/> class 
+        ///     with the specified error message.
+        /// </summary>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="CompositionContractMismatchException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.Message"/> property to its default value.
+        /// </param>
+        public CompositionContractMismatchException(string message)
+            : this(message, (Exception)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionContractMismatchException"/> class 
+        ///     with the specified error message and exception that is the cause of the  
+        ///     exception.
+        /// </summary>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="CompositionContractMismatchException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.Message"/> property to its default value.
+        /// </param>
+        /// <param name="innerException">
+        ///     The <see cref="Exception"/> that is the underlying cause of the 
+        ///     <see cref="CompositionContractMismatchException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.InnerException"/> property to <see langword="null"/>.
+        /// </param>
+        public CompositionContractMismatchException(string message, Exception innerException)
+            : base(message, innerException)
+        {
+        }
+
+#if FEATURE_SERIALIZATION
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionContractMismatchException"/> class 
+        ///     with the specified serialization data.
+        /// </summary>
+        /// <param name="info">
+        ///     The <see cref="SerializationInfo"/> that holds the serialized object data about the 
+        ///     <see cref="CompositionContractMismatchException"/>.
+        /// </param>
+        /// <param name="context">
+        ///     The <see cref="StreamingContext"/> that contains contextual information about the 
+        ///     source or destination.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="info"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="SerializationException">
+        ///     <paramref name="info"/> is missing a required value.
+        /// </exception>
+        /// <exception cref="InvalidCastException">
+        ///     <paramref name="info"/> contains a value that cannot be cast to the correct type.
+        /// </exception>
+        [System.Security.SecuritySafeCritical]
+        protected CompositionContractMismatchException(SerializationInfo info, StreamingContext context)
+            : base(info, context)
+        {
+        }
+
+#endif
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionError.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionError.cs
new file mode 100644
index 00000000000..c26b17b0853
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionError.cs
@@ -0,0 +1,187 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Globalization;
+using System.Security.Permissions;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Represents an error that occurs during composition.
+    /// </summary>
+    [Serializable]
+    [DebuggerTypeProxy(typeof(CompositionErrorDebuggerProxy))]
+    public class CompositionError
+    {
+        private readonly CompositionErrorId _id;
+        private readonly string _description;
+        private readonly Exception _exception;
+
+        private readonly ICompositionElement _element;
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionError"/> class
+        ///     with the specified error message.
+        /// </summary>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="CompositionError"/>; or <see langword="null"/> to set the 
+        ///     <see cref="Description"/> property to an empty string ("").
+        /// </param>
+        public CompositionError(string message)
+            : this(CompositionErrorId.Unknown, message, (ICompositionElement)null, (Exception)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionError"/> class
+        ///     with the specified error message and composition element that is the
+        ///     cause of the composition error.
+        /// </summary>
+        /// <param name="element">
+        ///     The <see cref="ICompositionElement"/> that is the cause of the
+        ///     <see cref="CompositionError"/>; or <see langword="null"/> to set
+        ///     the <see cref="CompositionError.Element"/> property to 
+        ///     <see langword="null"/>.
+        /// </param>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="CompositionError"/>; or <see langword="null"/> to set the 
+        ///     <see cref="Description"/> property to an empty string ("").
+        /// </param>
+        public CompositionError(string message, ICompositionElement element)
+            : this(CompositionErrorId.Unknown, message, element, (Exception)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionError"/> class 
+        ///     with the specified error message and exception that is the cause of the  
+        ///     composition error.
+        /// </summary>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="CompositionError"/>; or <see langword="null"/> to set the 
+        ///     <see cref="Description"/> property to an empty string ("").
+        /// </param>
+        /// <param name="exception">
+        ///     The <see cref="Exception"/> that is the underlying cause of the 
+        ///     <see cref="CompositionError"/>; or <see langword="null"/> to set
+        ///     the <see cref="CompositionError.Exception"/> property to <see langword="null"/>.
+        /// </param>
+        public CompositionError(string message, Exception exception)
+            : this(CompositionErrorId.Unknown, message, (ICompositionElement)null, exception)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionError"/> class 
+        ///     with the specified error message, and composition element and exception that 
+        ///     is the cause of the composition error.
+        /// </summary>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="CompositionError"/>; or <see langword="null"/> to set the 
+        ///     <see cref="Description"/> property to an empty string ("").
+        /// </param>
+        /// <param name="element">
+        ///     The <see cref="ICompositionElement"/> that is the cause of the
+        ///     <see cref="CompositionError"/>; or <see langword="null"/> to set
+        ///     the <see cref="CompositionError.Element"/> property to 
+        ///     <see langword="null"/>.
+        /// </param>
+        /// <param name="exception">
+        ///     The <see cref="Exception"/> that is the underlying cause of the 
+        ///     <see cref="CompositionError"/>; or <see langword="null"/> to set
+        ///     the <see cref="CompositionError.Exception"/> property to <see langword="null"/>.
+        /// </param>
+        public CompositionError(string message, ICompositionElement element, Exception exception)
+            : this(CompositionErrorId.Unknown, message, element, exception)
+        {
+        }
+
+        internal CompositionError(CompositionErrorId id, string description, ICompositionElement element, Exception exception)
+        {
+            _id = id;
+            _description = description ?? string.Empty;
+            _element = element;
+            _exception = exception;
+        }
+
+        /// <summary>
+        ///     Gets the composition element that is the cause of the error.
+        /// </summary>
+        /// <value>
+        ///     The <see cref="ICompositionElement"/> that is the cause of the
+        ///     <see cref="CompositionError"/>. The default is <see langword="null"/>.
+        /// </value>
+        public ICompositionElement Element
+        {
+            get { return _element; }
+        }
+
+        /// <summary>
+        ///     Gets the message that describes the composition error.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="String"/> containing a message that describes the
+        ///     <see cref="CompositionError"/>.
+        /// </value>
+        public string Description
+        {
+            get { return _description; }
+        }
+
+        /// <summary>
+        ///     Gets the exception that is the underlying cause of the composition error.
+        /// </summary>
+        /// <value>
+        ///     The <see cref="Exception"/> that is the underlying cause of the 
+        ///     <see cref="CompositionError"/>. The default is <see langword="null"/>.
+        /// </value>
+        public Exception Exception
+        {
+            get { return _exception; }
+        }
+
+        internal CompositionErrorId Id
+        {
+            get { return _id; }
+        }
+
+        internal Exception InnerException
+        {
+            get { return Exception; }
+        }
+
+        /// <summary>
+        ///     Returns a string representation of the composition error.
+        /// </summary>
+        /// <returns>
+        ///     A <see cref="String"/> containing the <see cref="Description"/> property.
+        /// </returns>
+        public override string ToString()
+        {
+            return this.Description;
+        }
+
+        internal static CompositionError Create(CompositionErrorId id, string format, params object[] parameters)
+        {
+            return Create(id, (ICompositionElement)null, (Exception)null, format, parameters);
+        }
+
+        internal static CompositionError Create(CompositionErrorId id, ICompositionElement element, string format, params object[] parameters)
+        {
+            return Create(id, element, (Exception)null, format, parameters);
+        }
+
+        internal static CompositionError Create(CompositionErrorId id, ICompositionElement element, Exception exception, string format, params object[] parameters)
+        {
+            return new CompositionError(id, string.Format(CultureInfo.CurrentCulture, format, parameters), element, exception);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionErrorDebuggerProxy.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionErrorDebuggerProxy.cs
new file mode 100644
index 00000000000..9530adb74cd
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionErrorDebuggerProxy.cs
@@ -0,0 +1,37 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition
+{
+    internal class CompositionErrorDebuggerProxy
+    {
+        private readonly CompositionError _error;
+
+        public CompositionErrorDebuggerProxy(CompositionError error)
+        {
+            Requires.NotNull(error, "error");
+
+            this._error = error;
+        }
+
+        public string Description
+        {
+            get { return this._error.Description; }
+        }
+
+        public Exception Exception
+        {
+            get { return this._error.Exception; }
+        }
+
+        public ICompositionElement Element
+        {
+            get { return this._error.Element; }
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionErrorId.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionErrorId.cs
new file mode 100644
index 00000000000..cc02cd5c629
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionErrorId.cs
@@ -0,0 +1,32 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+
+namespace System.ComponentModel.Composition
+{
+    internal enum CompositionErrorId : int
+    {
+        Unknown = 0,
+        InvalidExportMetadata,
+        ImportNotSetOnPart,
+        ImportEngine_ComposeTookTooManyIterations,
+        ImportEngine_ImportCardinalityMismatch,
+        ImportEngine_PartCycle,
+        ImportEngine_PartCannotSetImport,
+        ImportEngine_PartCannotGetExportedValue,
+        ImportEngine_PartCannotActivate,
+        ImportEngine_PreventedByExistingImport,
+        ImportEngine_InvalidStateForRecomposition,
+        ReflectionModel_ImportThrewException,
+        ReflectionModel_ImportNotAssignableFromExport,        
+        ReflectionModel_ImportCollectionNull,
+        ReflectionModel_ImportCollectionNotWritable,
+        ReflectionModel_ImportCollectionConstructionThrewException,
+        ReflectionModel_ImportCollectionGetThrewException,
+        ReflectionModel_ImportCollectionIsReadOnlyThrewException,
+        ReflectionModel_ImportCollectionClearThrewException,
+        ReflectionModel_ImportCollectionAddThrewException,
+        ReflectionModel_ImportManyOnParameterCanOnlyBeAssigned,
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionException.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionException.cs
new file mode 100644
index 00000000000..6bec825c4e1
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionException.cs
@@ -0,0 +1,342 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Globalization;
+using System.Linq;
+using System.Runtime.Serialization;
+using System.Security.Permissions;
+using System.Text;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition
+{
+
+    /// <summary>
+    ///     The exception that is thrown when one or more errors occur during composition.
+    /// </summary>
+    [Serializable]
+    [DebuggerTypeProxy(typeof(CompositionExceptionDebuggerProxy))]
+    [DebuggerDisplay("{Message}")]
+    public class CompositionException : Exception
+    {
+        const string ErrorsKey = "Errors";
+        private ReadOnlyCollection<CompositionError> _errors;
+
+#if FEATURE_SERIALIZATION
+        [Serializable]
+        private struct CompositionExceptionData : ISafeSerializationData
+        {
+            public CompositionError[] _errors;
+
+            void ISafeSerializationData.CompleteDeserialization(object obj)
+            {
+                CompositionException exception = obj as CompositionException;
+
+                exception._errors = new ReadOnlyCollection<CompositionError>(this._errors);
+            }
+        }
+#endif
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionException"/> class.
+        /// </summary>
+        public CompositionException()
+            : this((string)null, (Exception)null, (IEnumerable<CompositionError>)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionException"/> class 
+        ///     with the specified error message.
+        /// </summary>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="CompositionException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.Message"/> property to its default value.
+        /// </param>
+        public CompositionException(string message)
+            : this(message, (Exception)null, (IEnumerable<CompositionError>)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionException"/> class 
+        ///     with the specified error message and exception that is the cause of the  
+        ///     exception.
+        /// </summary>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="CompositionException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.Message"/> property to its default value.
+        /// </param>
+        /// <param name="innerException">
+        ///     The <see cref="Exception"/> that is the underlying cause of the 
+        ///     <see cref="ComposablePartException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.InnerException"/> property to <see langword="null"/>.
+        /// </param>
+        public CompositionException(string message, Exception innerException)
+            : this(message, innerException, (IEnumerable<CompositionError>)null)
+        {
+        }
+
+        internal CompositionException(CompositionError error)
+            : this(new CompositionError[] { error })
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionException"/> class 
+        ///     with the specified errors.
+        /// </summary>
+        /// <param name="errors">
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="CompositionError"/> objects
+        ///     representing the errors that are the cause of the 
+        ///     <see cref="CompositionException"/>; or <see langword="null"/> to set the 
+        ///     <see cref="Errors"/> property to an empty <see cref="IEnumerable{T}"/>.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="errors"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        public CompositionException(IEnumerable<CompositionError> errors)
+            : this((string)null, (Exception)null, errors)
+        {
+        }
+
+
+        internal CompositionException(string message, Exception innerException, IEnumerable<CompositionError> errors)
+            : base(message, innerException)
+        {
+            Requires.NullOrNotNullElements(errors, "errors");
+#if FEATURE_SERIALIZATION
+            SerializeObjectState += delegate(object exception, SafeSerializationEventArgs eventArgs)
+            {
+                var data = new CompositionExceptionData();
+                if(this._errors != null)
+                {
+                    data._errors = this._errors.Select(error => new CompositionError(
+                        error.Id, 
+                        error.Description,
+                        error.Element.ToSerializableElement(),
+                        error.Exception)).ToArray();
+                }
+                else
+                {
+                    data._errors = new CompositionError[0];
+                }
+
+                eventArgs.AddSerializedState(data);
+            };
+#endif
+            _errors = new ReadOnlyCollection<CompositionError>(errors == null ? new CompositionError[0] : errors.ToArray<CompositionError>());
+        }
+
+        /// <summary>
+        ///     Gets the errors that are the cause of the exception.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="CompositionError"/> objects
+        ///     representing the errors that are the cause of the 
+        ///     <see cref="CompositionException"/>.
+        /// </value>
+        public ReadOnlyCollection<CompositionError> Errors
+        {
+            get { return _errors; }
+        }
+
+
+        /// <summary>
+        ///     Gets a message that describes the exception.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="CompositionException"/>.
+        /// </value>
+        public override string Message
+        {
+            get
+            {
+                if (this.Errors.Count == 0)
+                {   // If there are no errors, then we simply return base.Message, 
+                    // which will either use the default Exception message, or if 
+                    // one was specified; the user supplied message.
+
+                    return base.Message;
+                }
+
+                return BuildDefaultMessage();
+            }
+        }
+
+        private string BuildDefaultMessage()
+        {
+            IEnumerable<IEnumerable<CompositionError>> paths = CalculatePaths(this);
+
+            StringBuilder writer = new StringBuilder();
+
+            WriteHeader(writer, this.Errors.Count, paths.Count());
+            WritePaths(writer, paths);
+
+            return writer.ToString();
+        }
+
+        private static void WriteHeader(StringBuilder writer, int errorsCount, int pathCount)
+        {
+            if (errorsCount > 1 && pathCount > 1)
+            {
+                // The composition produced multiple composition errors, with {0} root causes. The root causes are provided below.
+                writer.AppendFormat(
+                     CultureInfo.CurrentCulture,
+                     Strings.CompositionException_MultipleErrorsWithMultiplePaths,
+                     pathCount);
+            }
+            else if (errorsCount == 1 && pathCount > 1)
+            {
+                // The composition produced a single composition error, with {0} root causes. The root causes are provided below.
+                writer.AppendFormat(
+                     CultureInfo.CurrentCulture,
+                     Strings.CompositionException_SingleErrorWithMultiplePaths,
+                     pathCount);
+            }
+            else
+            {
+                Assumes.IsTrue(errorsCount == 1);
+                Assumes.IsTrue(pathCount == 1);
+                
+                // The composition produced a single composition error. The root cause is provided below.
+                writer.AppendFormat(
+                     CultureInfo.CurrentCulture,
+                     Strings.CompositionException_SingleErrorWithSinglePath,
+                     pathCount);
+            }
+
+            writer.Append(' ');
+            writer.AppendLine(Strings.CompositionException_ReviewErrorProperty);
+        }
+
+        private static void WritePaths(StringBuilder writer, IEnumerable<IEnumerable<CompositionError>> paths)
+        {
+            int ordinal = 0;
+            foreach (IEnumerable<CompositionError> path in paths)
+            {
+                ordinal++;
+                WritePath(writer, path, ordinal);
+            }
+        }
+
+        private static void WritePath(StringBuilder writer, IEnumerable<CompositionError> path, int ordinal)
+        {
+            writer.AppendLine();
+            writer.Append(ordinal.ToString(CultureInfo.CurrentCulture));
+            writer.Append(Strings.CompositionException_PathsCountSeparator);
+            writer.Append(' ');
+
+            WriteError(writer, path.First());
+
+            foreach (CompositionError error in path.Skip(1))
+            {
+                writer.AppendLine();
+                writer.Append(Strings.CompositionException_ErrorPrefix);
+                writer.Append(' ');
+                WriteError(writer, error);
+            }
+        }
+
+        private static void WriteError(StringBuilder writer, CompositionError error)
+        {
+            writer.AppendLine(error.Description);
+
+            if (error.Element != null)
+            {
+                WriteElementGraph(writer, error.Element);
+            }
+        }
+
+        private static void WriteElementGraph(StringBuilder writer, ICompositionElement element)
+        {
+            // Writes the composition element and its origins in the format:
+            // Element: Export --> Part --> PartDefinition --> Catalog
+
+            writer.AppendFormat(CultureInfo.CurrentCulture, Strings.CompositionException_ElementPrefix, element.DisplayName);
+
+            while ((element = element.Origin) != null)
+            {
+                writer.AppendFormat(CultureInfo.CurrentCulture, Strings.CompositionException_OriginFormat, Strings.CompositionException_OriginSeparator, element.DisplayName);
+            }
+
+            writer.AppendLine();
+        }
+
+        private static IEnumerable<IEnumerable<CompositionError>> CalculatePaths(CompositionException exception)
+        {
+            List<IEnumerable<CompositionError>> paths = new List<IEnumerable<CompositionError>>();
+
+            VisitContext context = new VisitContext();
+            context.Path = new Stack<CompositionError>();
+            context.LeafVisitor = path =>
+            {
+                // Take a snapshot of the path
+                paths.Add(path.Copy());
+            };
+
+            VisitCompositionException(exception, context);
+
+            return paths;
+        }
+
+        private static void VisitCompositionException(CompositionException exception, VisitContext context)
+        {
+            foreach (CompositionError error in exception.Errors)
+            {
+                VisitError(error, context);
+            }
+
+            if (exception.InnerException != null)
+            {
+                VisitException(exception.InnerException, context);
+            }
+        }
+
+        private static void VisitError(CompositionError error, VisitContext context)
+        {
+            context.Path.Push(error);
+
+            if (error.Exception == null)
+            {   // This error is a root cause, so write 
+                // out the stack from this point
+
+                context.LeafVisitor(context.Path);
+            }
+            else
+            {
+                VisitException(error.Exception, context);
+            }
+
+            context.Path.Pop();
+        }
+
+        private static void VisitException(Exception exception, VisitContext context)
+        {
+            CompositionException composition = exception as CompositionException;
+            if (composition != null)
+            {
+                VisitCompositionException(composition, context);
+            }
+            else
+            {
+                VisitError(new CompositionError(exception.Message, exception.InnerException), context);
+            }
+        }
+
+        private struct VisitContext
+        {
+            public Stack<CompositionError> Path;
+            public Action<Stack<CompositionError>> LeafVisitor;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionExceptionDebuggerProxy.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionExceptionDebuggerProxy.cs
new file mode 100644
index 00000000000..1db7863e409
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionExceptionDebuggerProxy.cs
@@ -0,0 +1,79 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Reflection;
+
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition
+{
+    internal class CompositionExceptionDebuggerProxy
+    {
+        private readonly CompositionException _exception;
+
+        public CompositionExceptionDebuggerProxy(CompositionException exception)
+        {
+            Requires.NotNull(exception, "exception");
+
+            this._exception = exception;
+        }
+
+        public ReadOnlyCollection<Exception> Exceptions
+        {
+            get
+            {
+                var errors = new List<Exception>();
+
+                // In here return a collection of all of the exceptions in the Errors collection
+                foreach (var error in _exception.Errors)
+                {
+                    if (error.Exception != null)
+                    {
+                        errors.Add(error.Exception);
+                    }
+                }
+                return errors.ToReadOnlyCollection<Exception>();
+            }
+        }
+
+        public string Message
+        {
+            get { return _exception.Message; }
+        }
+
+        public ReadOnlyCollection<Exception> RootCauses
+        {
+            get
+            {
+                var errors = new List<Exception>();
+
+                // In here return a collection of all of the exceptions in the Errors collection
+                foreach (var error in _exception.Errors)
+                {
+                    if (error.Exception != null)
+                    {
+                        var ce = error.Exception as CompositionException;
+                        if (ce != null)
+                        {
+                            var ceProxy = new CompositionExceptionDebuggerProxy(ce);
+                            if (ceProxy.RootCauses.Count > 0)
+                            {
+                                errors.AddRange(ceProxy.RootCauses);
+                                continue;
+                            }
+                        }
+                        errors.Add(error.Exception);
+                    }
+                }
+                return errors.ToReadOnlyCollection<Exception>();
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionResult.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionResult.cs
new file mode 100644
index 00000000000..f8c3c492ea3
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionResult.cs
@@ -0,0 +1,86 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using Microsoft.Internal.Collections;
+using System.ComponentModel.Composition.Hosting;
+
+namespace System.ComponentModel.Composition
+{
+    internal struct CompositionResult
+    {
+        public static readonly CompositionResult SucceededResult = new CompositionResult();
+        private readonly IEnumerable<CompositionError> _errors;
+
+        public CompositionResult(params CompositionError[] errors)
+            : this((IEnumerable<CompositionError>)errors)
+        {            
+        }
+
+        public CompositionResult(IEnumerable<CompositionError> errors)
+        {
+            this._errors = errors;
+        }
+
+        public bool Succeeded
+        {
+            get { return this._errors == null || !this._errors.FastAny(); }
+        }
+
+        public IEnumerable<CompositionError> Errors
+        {
+            get { return this._errors ?? Enumerable.Empty<CompositionError>(); }
+        }
+
+        public CompositionResult MergeResult(CompositionResult result)
+        {
+            if (this.Succeeded)
+            {
+                return result;
+            }
+            if (result.Succeeded)
+            {
+                return this;
+            }
+            return MergeErrors(result._errors);
+        }
+
+        public CompositionResult MergeError(CompositionError error)
+        {
+            return MergeErrors(new CompositionError[] { error });
+        }
+
+        public CompositionResult MergeErrors(IEnumerable<CompositionError> errors)
+        {
+            return new CompositionResult(this._errors.ConcatAllowingNull(errors));
+        }
+
+        public CompositionResult<T> ToResult<T>(T value)
+        {
+            return new CompositionResult<T>(value, this._errors); 
+        }
+
+        public void ThrowOnErrors()
+        {
+            ThrowOnErrors(null);
+        }
+
+        public void ThrowOnErrors(AtomicComposition atomicComposition)
+        {
+            if (!this.Succeeded)
+            {
+                if (atomicComposition == null)
+                {
+                    throw new CompositionException(this._errors);
+                }
+                else
+                {
+                    throw new ChangeRejectedException(this._errors);
+                }
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionResultOfT.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionResultOfT.cs
new file mode 100644
index 00000000000..65ee76df047
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CompositionResultOfT.cs
@@ -0,0 +1,79 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition
+{
+    internal struct CompositionResult<T>
+    {
+        private readonly IEnumerable<CompositionError> _errors;
+        private readonly T _value;
+        
+        public CompositionResult(T value)
+            : this(value, (CompositionError[])null)
+        {
+        }
+
+        public CompositionResult(params CompositionError[] errors)
+            : this(default(T), (IEnumerable<CompositionError>)errors)
+        {
+        }
+
+        public CompositionResult(IEnumerable<CompositionError> errors)
+            : this(default(T), errors)
+        {
+        }
+
+        internal CompositionResult(T value, IEnumerable<CompositionError> errors)
+        {
+            this._errors = errors;
+            this._value = value;
+        }
+
+        public bool Succeeded
+        {
+            get { return this._errors == null || !this._errors.FastAny(); }
+        }
+
+        public IEnumerable<CompositionError> Errors
+        {
+            get { return this._errors ?? Enumerable.Empty<CompositionError>(); }
+        }
+
+        /// <summary>
+        ///     Gets the value from the result, throwing a CompositionException if there are any errors.
+        /// </summary>
+        public T Value
+        {
+            get 
+            {
+                ThrowOnErrors();
+
+                return this._value; 
+            }
+        }
+
+        internal CompositionResult<TValue> ToResult<TValue>()
+        {
+            return new CompositionResult<TValue>(this._errors);
+        }
+
+        internal CompositionResult ToResult()
+        {
+            return new CompositionResult(this._errors);
+        }
+
+        private void ThrowOnErrors()
+        {
+            if (!this.Succeeded)
+            {
+                throw new CompositionException(this._errors);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ConstraintServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ConstraintServices.cs
new file mode 100644
index 00000000000..ebe2b6ca97d
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ConstraintServices.cs
@@ -0,0 +1,196 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Reflection;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition
+{
+    internal static class ConstraintServices
+    {
+        // NOTE : these are here as Reflection member search is pretty expensive, and we want that to be done once.
+        // Also, making these static would cause this class to fail loading if we rename members of ExportDefinition.
+        private static readonly PropertyInfo _exportDefinitionContractNameProperty = typeof(ExportDefinition).GetProperty("ContractName");
+        private static readonly PropertyInfo _exportDefinitionMetadataProperty = typeof(ExportDefinition).GetProperty("Metadata");
+        private static readonly MethodInfo _metadataContainsKeyMethod = typeof(IDictionary<string, object>).GetMethod("ContainsKey");
+        private static readonly MethodInfo _metadataItemMethod = typeof(IDictionary<string, object>).GetMethod("get_Item");
+        private static readonly MethodInfo _metadataEqualsMethod = typeof(object).GetMethod("Equals", new Type[] { typeof(object) });
+        private static readonly MethodInfo _typeIsInstanceOfTypeMethod = typeof(Type).GetMethod("IsInstanceOfType");
+
+        public static Expression<Func<ExportDefinition, bool>> CreateConstraint(string contractName, string requiredTypeIdentity, IEnumerable<KeyValuePair<string, Type>> requiredMetadata, CreationPolicy requiredCreationPolicy)
+        {
+            ParameterExpression parameter = Expression.Parameter(typeof(ExportDefinition), "exportDefinition");
+
+            Expression constraintBody = ConstraintServices.CreateContractConstraintBody(contractName, parameter);
+
+            if (!string.IsNullOrEmpty(requiredTypeIdentity))
+            {
+                Expression typeIdentityConstraintBody = ConstraintServices.CreateTypeIdentityContraint(requiredTypeIdentity, parameter);
+
+                constraintBody = Expression.AndAlso(constraintBody, typeIdentityConstraintBody);
+            }
+
+            if (requiredMetadata != null)
+            {
+                Expression metadataConstraintBody = ConstraintServices.CreateMetadataConstraintBody(requiredMetadata, parameter);
+                if (metadataConstraintBody != null)
+                {
+                    constraintBody = Expression.AndAlso(constraintBody, metadataConstraintBody);
+                }
+            }
+
+            if (requiredCreationPolicy != CreationPolicy.Any)
+            {
+                Expression policyConstraintBody = ConstraintServices.CreateCreationPolicyContraint(requiredCreationPolicy, parameter);
+
+                constraintBody = Expression.AndAlso(constraintBody, policyConstraintBody);
+            }
+
+            Expression<Func<ExportDefinition, bool>> constraint = Expression.Lambda<Func<ExportDefinition, bool>>(constraintBody, parameter);
+            return constraint;
+        }
+
+        private static Expression CreateContractConstraintBody(string contractName, ParameterExpression parameter)
+        {
+            Assumes.NotNull(parameter);
+
+            // export.ContractName=<contract>;
+            return Expression.Equal(
+                    Expression.Property(parameter, ConstraintServices._exportDefinitionContractNameProperty),
+                    Expression.Constant(contractName ?? string.Empty, typeof(string)));
+        }
+
+        private static Expression CreateMetadataConstraintBody(IEnumerable<KeyValuePair<string, Type>> requiredMetadata, ParameterExpression parameter)
+        {
+            Assumes.NotNull(requiredMetadata);
+            Assumes.NotNull(parameter);
+
+            Expression body = null;
+            foreach (KeyValuePair<string, Type> requiredMetadataItem in requiredMetadata)
+            {
+                // export.Metadata.ContainsKey(<metadataItem>)
+                Expression metadataItemExpression = CreateMetadataContainsKeyExpression(parameter, requiredMetadataItem.Key);
+
+                body = (body != null) ? Expression.AndAlso(body, metadataItemExpression) : metadataItemExpression;
+                body = Expression.AndAlso(body, CreateMetadataOfTypeExpression(parameter, requiredMetadataItem.Key, requiredMetadataItem.Value));
+            }
+
+            return body;
+        }
+
+        private static Expression CreateCreationPolicyContraint(CreationPolicy policy, ParameterExpression parameter)
+        {
+            Assumes.IsTrue(policy != CreationPolicy.Any);
+            Assumes.NotNull(parameter);
+
+            //    !definition.Metadata.ContainsKey(CompositionConstants.PartCreationPolicyMetadataName) ||
+            //        CreationPolicy.Any.Equals(definition.Metadata[CompositionConstants.PartCreationPolicyMetadataName]) ||
+            //        policy.Equals(definition.Metadata[CompositionConstants.PartCreationPolicyMetadataName]);
+
+            return  Expression.MakeBinary(ExpressionType.OrElse,
+                        Expression.MakeBinary(ExpressionType.OrElse,
+                            Expression.Not(CreateMetadataContainsKeyExpression(parameter, CompositionConstants.PartCreationPolicyMetadataName)),
+                            CreateMetadataValueEqualsExpression(parameter, CreationPolicy.Any, CompositionConstants.PartCreationPolicyMetadataName)),
+                        CreateMetadataValueEqualsExpression(parameter, policy, CompositionConstants.PartCreationPolicyMetadataName));
+        }
+
+        private static Expression CreateTypeIdentityContraint(string requiredTypeIdentity, ParameterExpression parameter)
+        {
+            Assumes.NotNull(requiredTypeIdentity);
+            Assumes.NotNull(parameter);
+
+            //    definition.Metadata.ContainsKey(CompositionServices.ExportTypeIdentity) &&
+            //        requiredTypeIdentity.Equals(definition.Metadata[CompositionConstants.ExportTypeIdentityMetadataName]);
+
+            return  Expression.MakeBinary(ExpressionType.AndAlso,
+                        CreateMetadataContainsKeyExpression(parameter, CompositionConstants.ExportTypeIdentityMetadataName),
+                        CreateMetadataValueEqualsExpression(parameter, requiredTypeIdentity, CompositionConstants.ExportTypeIdentityMetadataName));
+        }
+
+        private static Expression CreateMetadataContainsKeyExpression(ParameterExpression parameter, string constantKey)
+        {
+            Assumes.NotNull(parameter, constantKey);
+
+            // definition.Metadata.ContainsKey(constantKey)
+            return  Expression.Call(
+                        Expression.Property(parameter, ConstraintServices._exportDefinitionMetadataProperty),
+                        ConstraintServices._metadataContainsKeyMethod,
+                        Expression.Constant(constantKey));
+        }
+
+        private static Expression CreateMetadataOfTypeExpression(ParameterExpression parameter, string constantKey, Type constantType)
+        {
+            Assumes.NotNull(parameter, constantKey);
+            Assumes.NotNull(parameter, constantType);
+
+            // constantType.IsInstanceOfType(definition.Metadata[constantKey])
+            return Expression.Call(
+                            Expression.Constant(constantType, typeof(Type)),
+                            ConstraintServices._typeIsInstanceOfTypeMethod,
+                            Expression.Call(
+                                Expression.Property(parameter, ConstraintServices._exportDefinitionMetadataProperty),
+                                ConstraintServices._metadataItemMethod,
+                                Expression.Constant(constantKey))
+                            );
+        }
+
+        private static Expression CreateMetadataValueEqualsExpression(ParameterExpression parameter, object constantValue, string metadataName)
+        {
+            Assumes.NotNull(parameter, constantValue);
+
+            // constantValue.Equals(definition.Metadata[CompositionServices.PartCreationPolicyMetadataName])
+            return  Expression.Call(
+                        Expression.Constant(constantValue),
+                        ConstraintServices._metadataEqualsMethod,
+                        Expression.Call(
+                            Expression.Property(parameter, ConstraintServices._exportDefinitionMetadataProperty),
+                            ConstraintServices._metadataItemMethod,
+                            Expression.Constant(metadataName)));
+        }
+
+        public static Expression<Func<ExportDefinition, bool>> CreatePartCreatorConstraint(Expression<Func<ExportDefinition, bool>> baseConstraint, ImportDefinition productImportDefinition)
+        {
+            ParameterExpression exportDefinitionParameter = baseConstraint.Parameters[0];
+
+            // exportDefinition.Metadata
+            Expression metadataExpression = Expression.Property(exportDefinitionParameter, ConstraintServices._exportDefinitionMetadataProperty);
+
+            // exportDefinition.Metadata.ContainsKey("ProductDefinition")
+            Expression containsProductExpression = Expression.Call(
+                metadataExpression,
+                ConstraintServices._metadataContainsKeyMethod,
+                Expression.Constant(CompositionConstants.ProductDefinitionMetadataName));
+
+            // exportDefinition.Metadata["ProductDefinition"]
+            Expression productExportDefinitionExpression = Expression.Call(
+                    metadataExpression,
+                    ConstraintServices._metadataItemMethod,
+                    Expression.Constant(CompositionConstants.ProductDefinitionMetadataName));
+
+            // ProductImportDefinition.Contraint((ExportDefinition)exportDefinition.Metadata["ProductDefinition"])
+            Expression productMatchExpression =
+                Expression.Invoke(productImportDefinition.Constraint,
+                    Expression.Convert(productExportDefinitionExpression, typeof(ExportDefinition)));
+
+            // baseContraint(exportDefinition) &&
+            // exportDefinition.Metadata.ContainsKey("ProductDefinition") &&
+            // ProductImportDefinition.Contraint((ExportDefinition)exportDefinition.Metadata["ProductDefinition"])
+            Expression<Func<ExportDefinition, bool>> constraint =
+                 Expression.Lambda<Func<ExportDefinition, bool>>(
+                    Expression.AndAlso(
+                        baseConstraint.Body,
+                        Expression.AndAlso(
+                           containsProductExpression,
+                           productMatchExpression)),
+                    exportDefinitionParameter);
+
+            return constraint;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ContractNameServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ContractNameServices.cs
new file mode 100644
index 00000000000..962e172947c
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ContractNameServices.cs
@@ -0,0 +1,342 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Reflection;
+using System.Text;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition
+{
+    internal static class ContractNameServices
+    {
+        const char NamespaceSeparator = '.';
+        const char ArrayOpeningBracket = '[';
+        const char ArrayClosingBracket = ']';
+        const char ArraySeparator = ',';
+        const char PointerSymbol = '*';
+        const char ReferenceSymbol = '&';
+        const char GenericArityBackQuote = '`';
+        const char NestedClassSeparator = '+';
+        const char ContractNameGenericOpeningBracket = '(';
+        const char ContractNameGenericClosingBracket = ')';
+        const char ContractNameGenericArgumentSeparator = ',';
+        const char CustomModifiersSeparator = ' ';
+        const char GenericFormatOpeningBracket = '{';
+        const char GenericFormatClosingBracket = '}';
+
+        [ThreadStatic]
+        private static Dictionary<Type, string> typeIdentityCache;
+
+        private static Dictionary<Type, string> TypeIdentityCache
+        {
+            get
+            {
+                return typeIdentityCache = typeIdentityCache ?? new Dictionary<Type, string>();
+            }
+        }
+
+        internal static string GetTypeIdentity(Type type)
+        {
+            return GetTypeIdentity(type, true);
+        }
+
+        internal static string GetTypeIdentity(Type type, bool formatGenericName)
+        {
+            Assumes.NotNull(type);
+            string typeIdentity = null;
+
+            if (!TypeIdentityCache.TryGetValue(type, out typeIdentity))
+            {
+                if (!type.IsAbstract && type.IsSubclassOf(typeof(Delegate)))
+                {
+                    MethodInfo method = type.GetMethod("Invoke");
+                    typeIdentity = ContractNameServices.GetTypeIdentityFromMethod(method);
+                }
+                else if (type.IsGenericParameter)
+                {
+                    StringBuilder typeIdentityStringBuilder = new StringBuilder();
+                    WriteTypeArgument(typeIdentityStringBuilder, false, type, formatGenericName);
+                    typeIdentityStringBuilder.Remove(typeIdentityStringBuilder.Length - 1, 1);
+                    typeIdentity = typeIdentityStringBuilder.ToString();
+                }
+                else
+                {
+                    StringBuilder typeIdentityStringBuilder = new StringBuilder();
+                    WriteTypeWithNamespace(typeIdentityStringBuilder, type, formatGenericName);
+                    typeIdentity = typeIdentityStringBuilder.ToString();
+                }
+
+                Assumes.IsTrue(!string.IsNullOrEmpty(typeIdentity));
+                TypeIdentityCache.Add(type, typeIdentity);
+            }
+
+            return typeIdentity;
+        }
+
+        internal static string GetTypeIdentityFromMethod(MethodInfo method)
+        {
+            return GetTypeIdentityFromMethod(method, true);
+        }
+
+        internal static string GetTypeIdentityFromMethod(MethodInfo method, bool formatGenericName)
+        {
+            StringBuilder methodNameStringBuilder = new StringBuilder();
+
+            WriteTypeWithNamespace(methodNameStringBuilder, method.ReturnType, formatGenericName);
+
+            methodNameStringBuilder.Append("(");
+
+            ParameterInfo[] parameters = method.GetParameters();
+
+            for (int i = 0; i < parameters.Length; i++)
+            {
+                if (i != 0)
+                {
+                    methodNameStringBuilder.Append(",");
+                }
+
+                WriteTypeWithNamespace(methodNameStringBuilder, parameters[i].ParameterType, formatGenericName);
+            }
+            methodNameStringBuilder.Append(")");
+
+            return methodNameStringBuilder.ToString();
+        }
+
+        private static void WriteTypeWithNamespace(StringBuilder typeName, Type type, bool formatGenericName)
+        {
+            // Writes type with namesapce
+            if (!string.IsNullOrEmpty(type.Namespace))
+            {
+                typeName.Append(type.Namespace);
+                typeName.Append(NamespaceSeparator);
+            }
+            WriteType(typeName, type, formatGenericName);
+        }
+
+        private static void WriteType(StringBuilder typeName, Type type, bool formatGenericName)
+        {
+            // Writes type name
+            if (type.IsGenericType)
+            {
+                //
+                // Reflection format stores all the generic arguments (including the ones for parent types) on the leaf type.
+                // These arguments are placed in a queue and are written out based on generic arity (`X) of each type
+                //
+                Queue<Type> genericTypeArguments = new Queue<Type>(type.GetGenericArguments());
+                WriteGenericType(typeName, type, type.IsGenericTypeDefinition, genericTypeArguments, formatGenericName);
+                Assumes.IsTrue(genericTypeArguments.Count == 0, "Expecting genericTypeArguments queue to be empty.");
+            }
+            else
+            {
+                WriteNonGenericType(typeName, type, formatGenericName);
+            }
+        }
+
+        private static void WriteNonGenericType(StringBuilder typeName, Type type, bool formatGenericName)
+        {
+            //
+            // Writes non-generic type
+            //
+            if (type.DeclaringType != null)
+            {
+                WriteType(typeName, type.DeclaringType, formatGenericName);
+                typeName.Append(NestedClassSeparator);
+            }
+            if (type.IsArray)
+            {
+                WriteArrayType(typeName, type, formatGenericName);
+            }
+            else if (type.IsPointer)
+            {
+                WritePointerType(typeName, type, formatGenericName);
+            }
+            else if (type.IsByRef)
+            {
+                WriteByRefType(typeName, type, formatGenericName);
+            }
+            else
+            {
+                typeName.Append(type.Name);
+            }
+        }
+
+        private static void WriteArrayType(StringBuilder typeName, Type type, bool formatGenericName)
+        {
+            //
+            // Writes array type  e.g <TypeName>[]
+            // Note that jagged arrays are stored in reverse order
+            // e.g. C#: Int32[][,]  Reflection: Int32[,][]
+            // we are following C# order for arrays
+            //
+            Type rootElementType = FindArrayElementType(type);
+            WriteType(typeName, rootElementType, formatGenericName);
+            Type elementType = type;
+            do
+            {
+                WriteArrayTypeDimensions(typeName, elementType);
+            }
+            while ((elementType = elementType.GetElementType()) != null && elementType.IsArray);
+        }
+
+        private static void WritePointerType(StringBuilder typeName, Type type, bool formatGenericName)
+        {
+            //
+            // Writes pointer type  e.g <TypeName>*
+            //
+            WriteType(typeName, type.GetElementType(), formatGenericName);
+            typeName.Append(PointerSymbol);
+        }
+
+        private static void WriteByRefType(StringBuilder typeName, Type type, bool formatGenericName)
+        {
+            //
+            // Writes by ref type e.g <TypeName>&
+            //
+            WriteType(typeName, type.GetElementType(), formatGenericName);
+            typeName.Append(ReferenceSymbol);
+        }
+
+        private static void WriteArrayTypeDimensions(StringBuilder typeName, Type type)
+        {
+            //
+            // Writes array type dimensions e.g. [,,]
+            //
+            typeName.Append(ArrayOpeningBracket);
+            int rank = type.GetArrayRank();
+            for (int i = 1; i < rank; i++)
+            {
+                typeName.Append(ArraySeparator);
+            }
+            typeName.Append(ArrayClosingBracket);
+        }
+
+        private static void WriteGenericType(StringBuilder typeName, Type type, bool isDefinition, Queue<Type> genericTypeArguments, bool formatGenericName)
+        {
+            //
+            // Writes generic type including parent generic types
+            // genericTypeArguments contains type arguments obtained from the most nested type
+            // isDefinition parameter indicates if we are dealing with generic type definition
+            //
+            if (type.DeclaringType != null)
+            {
+                if (type.DeclaringType.IsGenericType)
+                {
+                    WriteGenericType(typeName, type.DeclaringType, isDefinition, genericTypeArguments, formatGenericName);
+                }
+                else
+                {
+                    WriteNonGenericType(typeName, type.DeclaringType, formatGenericName);
+                }
+                typeName.Append(NestedClassSeparator);
+            }
+            WriteGenericTypeName(typeName, type, isDefinition, genericTypeArguments, formatGenericName);
+        }
+
+        private static void WriteGenericTypeName(StringBuilder typeName, Type type, bool isDefinition, Queue<Type> genericTypeArguments, bool formatGenericName)
+        {
+            //
+            // Writes generic type name, e.g. generic name and generic arguments
+            //
+            Assumes.IsTrue(type.IsGenericType, "Expecting type to be a generic type");
+            int genericArity = GetGenericArity(type);
+            string genericTypeName = FindGenericTypeName(type.GetGenericTypeDefinition().Name);
+            typeName.Append(genericTypeName);
+            WriteTypeArgumentsString(typeName, genericArity, isDefinition, genericTypeArguments, formatGenericName);
+        }
+
+        private static void WriteTypeArgumentsString(StringBuilder typeName, int argumentsCount, bool isDefinition, Queue<Type> genericTypeArguments, bool formatGenericName)
+        {
+            //
+            // Writes type arguments in brackets, e.g. (<contract_name1>, <contract_name2>, ...)
+            //
+            if (argumentsCount == 0)
+            {
+                return;
+            }
+            typeName.Append(ContractNameGenericOpeningBracket);
+            for (int i = 0; i < argumentsCount; i++)
+            {
+                Assumes.IsTrue(genericTypeArguments.Count > 0, "Expecting genericTypeArguments to contain at least one Type");
+                Type genericTypeArgument = genericTypeArguments.Dequeue();
+                WriteTypeArgument(typeName, isDefinition, genericTypeArgument, formatGenericName);
+            }
+            typeName.Remove(typeName.Length - 1, 1);
+            typeName.Append(ContractNameGenericClosingBracket);
+        }
+
+        private static void WriteTypeArgument(StringBuilder typeName, bool isDefinition, Type genericTypeArgument, bool formatGenericName)
+        {
+            if (!isDefinition && !genericTypeArgument.IsGenericParameter)
+            {
+                WriteTypeWithNamespace(typeName, genericTypeArgument, formatGenericName);
+            }
+
+            if (formatGenericName && genericTypeArgument.IsGenericParameter)
+            {
+                typeName.Append(GenericFormatOpeningBracket);
+                typeName.Append(genericTypeArgument.GenericParameterPosition);
+                typeName.Append(GenericFormatClosingBracket);
+            }
+            typeName.Append(ContractNameGenericArgumentSeparator);
+        }
+
+        //internal for testability
+        internal static void WriteCustomModifiers(StringBuilder typeName, string customKeyword, Type[] types, bool formatGenericName)
+        {
+            //
+            // Writes custom modifiers in the format: customKeyword(<contract_name>,<contract_name>,...)
+            //
+            typeName.Append(CustomModifiersSeparator);
+            typeName.Append(customKeyword);
+            Queue<Type> typeArguments = new Queue<Type>(types);
+            WriteTypeArgumentsString(typeName, types.Length, false, typeArguments, formatGenericName);
+            Assumes.IsTrue(typeArguments.Count == 0, "Expecting genericTypeArguments queue to be empty.");
+        }
+
+        private static Type FindArrayElementType(Type type)
+        {
+            //
+            // Gets array element type by calling GetElementType() until the element is not an array
+            //
+            Type elementType = type;
+            while ((elementType = elementType.GetElementType()) != null && elementType.IsArray) { }
+            return elementType;
+        }
+
+        private static string FindGenericTypeName(string genericName)
+        {
+            //
+            // Gets generic type name omitting the backquote and arity indicator
+            // List`1 -> List
+            // Arity indicator is returned as output parameter
+            //
+            int indexOfBackQuote = genericName.IndexOf(GenericArityBackQuote);
+            if (indexOfBackQuote > -1)
+            {
+                genericName = genericName.Substring(0, indexOfBackQuote);
+            }
+            return genericName;
+        }
+
+        private static int GetGenericArity(Type type)
+        {
+            if (type.DeclaringType == null)
+            {
+                return type.GetGenericArguments().Length;
+            }
+
+            // The generic arity is equal to the difference in the number of generic arguments
+            // from the type and the declaring type.
+
+            int delclaringTypeGenericArguments = type.DeclaringType.GetGenericArguments().Length;
+            int typeGenericArguments = type.GetGenericArguments().Length;
+
+            Assumes.IsTrue(typeGenericArguments >= delclaringTypeGenericArguments);
+
+            return typeGenericArguments - delclaringTypeGenericArguments;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CreationPolicy.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CreationPolicy.cs
new file mode 100644
index 00000000000..13302bb3ea6
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/CreationPolicy.cs
@@ -0,0 +1,43 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    /// Option placed on a type that controls when the <see cref="CompositionContainer"/> creates 
+    /// a new instance of a <see cref="ComposablePart"/>.
+    /// </summary>
+    public enum CreationPolicy : int
+    {
+        /// <summary>
+        /// Let the <see cref="CompositionContainer"/> choose the most appropriate <see cref="CreationPolicy"/>
+        /// for the part given the current context. This is the default <see cref="CreationPolicy"/>, with
+        /// the <see cref="CompositionContainer"/> choosing <see cref="CreationPolicy.Shared"/> by default
+        /// unless the <see cref="ComposablePart"/> or importer requests <see cref="CreationPolicy.NonShared"/>.
+        /// </summary>
+        Any = 0,
+
+        /// <summary>
+        /// A single shared instance of the associated <see cref="ComposablePart"/> will be created
+        /// by the <see cref="CompositionContainer"/> and shared by all requestors.
+        /// </summary>
+        Shared = 1,
+
+        /// <summary>
+        /// A new non-shared instance of the associated <see cref="ComposablePart"/> will be created
+        /// by the <see cref="CompositionContainer"/> for every requestor.
+        /// </summary>
+        NonShared = 2,
+
+        /// <summary>
+        /// Each new non-shared instance of the part is created by a new <see cref="CompositionContainer"/> for every requestor.  Shared instances of the parts dependencies
+        /// are unique to this instance.
+        /// For this release can only be applied to imports of type  <see cref="ExportFactory<T>"/>
+        /// </summary>
+        NewScope = 3,
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/CompositionTrace.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/CompositionTrace.cs
new file mode 100644
index 00000000000..2f8e56bfeb1
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/CompositionTrace.cs
@@ -0,0 +1,108 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using Microsoft.Internal;
+using System.Reflection;
+
+namespace System.ComponentModel.Composition.Diagnostics
+{
+    internal static class CompositionTrace
+    {
+        internal static void PartDefinitionResurrected(ComposablePartDefinition definition)
+        {
+            Assumes.NotNull(definition);
+
+            if (CompositionTraceSource.CanWriteInformation)
+            {
+                CompositionTraceSource.WriteInformation(CompositionTraceId.Rejection_DefinitionResurrected, 
+                                                        Strings.CompositionTrace_Rejection_DefinitionResurrected, 
+                                                        definition.GetDisplayName());
+            }
+        }
+
+        internal static void PartDefinitionRejected(ComposablePartDefinition definition, ChangeRejectedException exception)
+        {
+            Assumes.NotNull(definition, exception);
+
+            if (CompositionTraceSource.CanWriteWarning)
+            {
+                CompositionTraceSource.WriteWarning(CompositionTraceId.Rejection_DefinitionRejected, 
+                                                    Strings.CompositionTrace_Rejection_DefinitionRejected, 
+                                                    definition.GetDisplayName(), 
+                                                    exception.Message);
+            }
+        }
+
+#if FEATURE_REFLECTIONFILEIO
+
+        internal static void AssemblyLoadFailed(DirectoryCatalog catalog, string fileName, Exception exception)
+        {
+            Assumes.NotNull(catalog, exception);
+            Assumes.NotNullOrEmpty(fileName);            
+
+            if (CompositionTraceSource.CanWriteWarning)
+            {
+                CompositionTraceSource.WriteWarning(CompositionTraceId.Discovery_AssemblyLoadFailed, 
+                                                    Strings.CompositionTrace_Discovery_AssemblyLoadFailed, 
+                                                    catalog.GetDisplayName(),
+                                                    fileName, 
+                                                    exception.Message);
+            }
+        }
+
+#endif //FEATURE_REFLECTIONFILEIO
+
+        internal static void DefinitionMarkedWithPartNotDiscoverableAttribute(Type type)
+        {
+            Assumes.NotNull(type);
+
+            if (CompositionTraceSource.CanWriteInformation)
+            {
+                CompositionTraceSource.WriteInformation(CompositionTraceId.Discovery_DefinitionMarkedWithPartNotDiscoverableAttribute, 
+                                                        Strings.CompositionTrace_Discovery_DefinitionMarkedWithPartNotDiscoverableAttribute, 
+                                                        type.GetDisplayName());
+            }
+        }
+
+        internal static void DefinitionMismatchedExportArity(Type type, MemberInfo member)
+        {
+            Assumes.NotNull(type);
+            Assumes.NotNull(member);
+
+            if (CompositionTraceSource.CanWriteInformation)
+            {
+                CompositionTraceSource.WriteInformation(CompositionTraceId.Discovery_DefinitionMismatchedExportArity,
+                                                        Strings.CompositionTrace_Discovery_DefinitionMismatchedExportArity,
+                                                        type.GetDisplayName(), member.GetDisplayName());
+            }
+        }
+
+        internal static void DefinitionContainsNoExports(Type type)
+        {
+            Assumes.NotNull(type);
+
+            if (CompositionTraceSource.CanWriteInformation)
+            {
+                CompositionTraceSource.WriteInformation(CompositionTraceId.Discovery_DefinitionContainsNoExports,
+                                                        Strings.CompositionTrace_Discovery_DefinitionContainsNoExports,
+                                                        type.GetDisplayName());
+            }
+        }
+
+        internal static void MemberMarkedWithMultipleImportAndImportMany(ReflectionItem item)
+        {
+            Assumes.NotNull(item);
+
+            if (CompositionTraceSource.CanWriteError)
+            {
+                CompositionTraceSource.WriteError(CompositionTraceId.Discovery_MemberMarkedWithMultipleImportAndImportMany,
+                                                  Strings.CompositionTrace_Discovery_MemberMarkedWithMultipleImportAndImportMany,
+                                                  item.GetDisplayName());
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/CompositionTraceId.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/CompositionTraceId.cs
new file mode 100644
index 00000000000..7c8a0ac2646
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/CompositionTraceId.cs
@@ -0,0 +1,24 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+
+namespace System.ComponentModel.Composition.Diagnostics
+{
+    // NOTE: Do not change the trace ids of values that have already shipped, 
+    // these leak out to TraceListerners which could take a dependency on them.
+    // This enum is a ushort deliberately, the maximum value of a trace id is 65535.
+    internal enum CompositionTraceId : ushort
+    {
+        // Rejection
+
+        Rejection_DefinitionRejected = 1,
+        Rejection_DefinitionResurrected = 2,
+
+        Discovery_AssemblyLoadFailed = 3,
+        Discovery_DefinitionMarkedWithPartNotDiscoverableAttribute = 4,
+        Discovery_DefinitionMismatchedExportArity = 5,
+        Discovery_DefinitionContainsNoExports = 6,
+        Discovery_MemberMarkedWithMultipleImportAndImportMany = 7,
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/CompositionTraceSource.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/CompositionTraceSource.cs
new file mode 100644
index 00000000000..ddf2f34ae3e
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/CompositionTraceSource.cs
@@ -0,0 +1,58 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Diagnostics
+{
+    internal static class CompositionTraceSource
+    {
+#if FEATURE_TRACING
+        private static readonly TraceSourceTraceWriter Source = new TraceSourceTraceWriter();
+#else
+        private static readonly DebuggerTraceWriter Source = new DebuggerTraceWriter();
+#endif
+
+        public static bool CanWriteInformation
+        {
+            get { return Source.CanWriteInformation; }
+        }
+
+        public static bool CanWriteWarning
+        {
+            get { return Source.CanWriteWarning; }
+        }
+
+        public static bool CanWriteError
+        {
+            get { return Source.CanWriteError; }
+        }
+
+        public static void WriteInformation(CompositionTraceId traceId, string format, params object[] arguments)
+        {
+            EnsureEnabled(CanWriteInformation);
+
+            Source.WriteInformation(traceId, format, arguments);
+        }
+
+        public static void WriteWarning(CompositionTraceId traceId, string format, params object[] arguments)
+        {
+            EnsureEnabled(CanWriteWarning);
+
+            Source.WriteWarning(traceId, format, arguments);
+        }
+
+        public static void WriteError(CompositionTraceId traceId, string format, params object[] arguments)
+        {
+            EnsureEnabled(CanWriteError);
+
+            Source.WriteError(traceId, format, arguments);
+        }
+
+        private static void EnsureEnabled(bool condition)
+        {
+            Assumes.IsTrue(condition, "To avoid unnecessary work when a trace level has not been enabled, check CanWriteXXX before calling this method.");
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/SilverlightTraceWriter.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/SilverlightTraceWriter.cs
new file mode 100644
index 00000000000..2a1e1fec124
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/SilverlightTraceWriter.cs
@@ -0,0 +1,89 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+#if !FEATURE_TRACING
+using System;
+using System.Diagnostics;
+using System.Globalization;
+using System.Text;
+
+namespace System.ComponentModel.Composition.Diagnostics
+{
+    internal sealed class DebuggerTraceWriter : TraceWriter
+    {
+        private static readonly string SourceName = "System.ComponentModel.Composition";
+
+        public override bool CanWriteInformation
+        {
+            get { return false; }
+        }
+
+        public override bool CanWriteWarning
+        {
+            get { return Debugger.IsLogging(); }
+        }
+
+        public override bool CanWriteError
+        {
+            get { return Debugger.IsLogging(); }
+        }
+
+        public override void WriteInformation(CompositionTraceId traceId, string format, params object[] arguments)
+        {
+            WriteEvent(TraceEventType.Information, traceId, format, arguments);
+        }
+
+        public override void WriteWarning(CompositionTraceId traceId, string format, params object[] arguments)
+        {
+            WriteEvent(TraceEventType.Warning, traceId, format, arguments);
+        }
+
+        public override void WriteError(CompositionTraceId traceId, string format, params object[] arguments)
+        {
+            WriteEvent(TraceEventType.Error, traceId, format, arguments);
+        }
+
+        private static void WriteEvent(TraceEventType eventType, CompositionTraceId traceId, string format, params object[] arguments)
+        {
+            if (!Debugger.IsLogging())
+            {
+                return;
+            }
+
+            string logMessage = CreateLogMessage(eventType, traceId, format, arguments);
+            Debugger.Log(0, null, logMessage);
+        }
+
+        internal static string CreateLogMessage(TraceEventType eventType, CompositionTraceId traceId, string format, params object[] arguments)
+        {
+            StringBuilder messageBuilder = new StringBuilder();
+
+            // Format taken from TraceListener.TraceEvent in full framework
+            messageBuilder.AppendFormat(CultureInfo.InvariantCulture, "{0} {1}: {2} : ", 
+                SourceName, eventType.ToString(), (int)traceId);
+
+            if (arguments == null)
+            {
+                messageBuilder.Append(format);
+            }
+            else
+            {
+                messageBuilder.AppendFormat(CultureInfo.InvariantCulture, format, arguments);
+            }
+
+            messageBuilder.AppendLine();
+
+            return messageBuilder.ToString();
+        }
+
+        // Copied from TraceEventType in full framework
+        internal enum TraceEventType
+        {
+            Error = 2,
+            Warning = 4,
+            Information = 8,
+        }
+    }
+}
+
+#endif //!FEATURE_TRACING
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/TraceSourceTraceWriter.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/TraceSourceTraceWriter.cs
new file mode 100644
index 00000000000..7cb11adcb6c
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/TraceSourceTraceWriter.cs
@@ -0,0 +1,54 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+#if FEATURE_TRACING
+
+using System;
+using System.Diagnostics;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Diagnostics
+{
+    // Represents a trace writer that writes to a System.Diagnostics TraceSource
+    internal sealed class TraceSourceTraceWriter : TraceWriter
+    {
+        internal static readonly TraceSource Source = new TraceSource("System.ComponentModel.Composition", SourceLevels.Warning);
+
+        public override bool CanWriteInformation
+        {
+            get { return Source.Switch.ShouldTrace(TraceEventType.Information); }
+        }
+
+        public override bool CanWriteWarning
+        {
+            get { return Source.Switch.ShouldTrace(TraceEventType.Warning); }
+        }
+
+        public override bool CanWriteError
+        {
+            get { return Source.Switch.ShouldTrace(TraceEventType.Error); }
+        }
+
+        public override void WriteInformation(CompositionTraceId traceId, string format, params object[] arguments)
+        {
+            WriteEvent(TraceEventType.Information, traceId, format, arguments);
+        }
+
+        public override void WriteWarning(CompositionTraceId traceId, string format, params object[] arguments)
+        {
+            WriteEvent(TraceEventType.Warning, traceId, format, arguments);
+        }
+
+        public override void WriteError(CompositionTraceId traceId, string format, params object[] arguments)
+        {
+            WriteEvent(TraceEventType.Error, traceId, format, arguments);
+        }
+
+        private static void WriteEvent(TraceEventType eventType, CompositionTraceId traceId, string format, params object[] arguments)
+        {
+            Source.TraceEvent(eventType, (int)traceId, format, arguments);
+        }
+    }
+}
+
+#endif //FEATURE_TRACING
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/TraceWriter.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/TraceWriter.cs
new file mode 100644
index 00000000000..4be992a2784
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Diagnostics/TraceWriter.cs
@@ -0,0 +1,33 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+
+using System;
+
+namespace System.ComponentModel.Composition.Diagnostics
+{
+    internal abstract class TraceWriter
+    {
+        public abstract bool CanWriteInformation
+        {
+            get;
+        }
+
+        public abstract bool CanWriteWarning
+        {
+            get;
+        }
+
+        public abstract bool CanWriteError
+        {
+            get;
+        }
+
+        public abstract void WriteInformation(CompositionTraceId traceId, string format, params object[] arguments);
+
+        public abstract void WriteWarning(CompositionTraceId traceId, string format, params object[] arguments);
+
+        public abstract void WriteError(CompositionTraceId traceId, string format, params object[] arguments);
+    }
+}
+
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ErrorBuilder.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ErrorBuilder.cs
new file mode 100644
index 00000000000..83eb9d6e71a
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ErrorBuilder.cs
@@ -0,0 +1,102 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition
+{
+    internal static class ErrorBuilder
+    {
+        public static CompositionError PreventedByExistingImport(ComposablePart part, ImportDefinition import)
+        {
+            return CompositionError.Create(
+                CompositionErrorId.ImportEngine_PreventedByExistingImport,
+                Strings.ImportEngine_PreventedByExistingImport,
+                import.ToElement().DisplayName,
+                part.ToElement().DisplayName);
+        }
+
+        public static CompositionError InvalidStateForRecompposition(ComposablePart part)
+        {
+            return CompositionError.Create(
+                CompositionErrorId.ImportEngine_InvalidStateForRecomposition,
+                Strings.ImportEngine_InvalidStateForRecomposition,
+                part.ToElement().DisplayName);
+        }
+
+        public static CompositionError ComposeTookTooManyIterations(int maximumNumberOfCompositionIterations)
+        {
+            return CompositionError.Create(
+                CompositionErrorId.ImportEngine_ComposeTookTooManyIterations,
+                Strings.ImportEngine_ComposeTookTooManyIterations,
+                maximumNumberOfCompositionIterations);
+        }
+
+        public static CompositionError CreateImportCardinalityMismatch(ImportCardinalityMismatchException exception, ImportDefinition definition)
+        {
+            Assumes.NotNull(exception, definition);
+
+            return CompositionError.Create(
+                CompositionErrorId.ImportEngine_ImportCardinalityMismatch, 
+                exception.Message,
+                definition.ToElement(), 
+                (Exception)null);
+        }
+
+        public static CompositionError CreatePartCannotActivate(ComposablePart part, Exception innerException)
+        {
+            Assumes.NotNull(part, innerException);
+
+            ICompositionElement element = part.ToElement();
+            return CompositionError.Create(
+                CompositionErrorId.ImportEngine_PartCannotActivate,
+                element,
+                innerException,
+                Strings.ImportEngine_PartCannotActivate,
+                element.DisplayName);
+        }
+
+        public static CompositionError CreatePartCannotSetImport(ComposablePart part, ImportDefinition definition, Exception innerException)
+        {
+            Assumes.NotNull(part, definition, innerException);
+
+            ICompositionElement element = definition.ToElement();
+            return CompositionError.Create(
+                CompositionErrorId.ImportEngine_PartCannotSetImport,
+                element,
+                innerException,
+                Strings.ImportEngine_PartCannotSetImport,
+                element.DisplayName,
+                part.ToElement().DisplayName);
+        }
+
+        public static CompositionError CreateCannotGetExportedValue(ComposablePart part, ExportDefinition definition, Exception innerException)
+        {
+            Assumes.NotNull(part, definition, innerException);
+
+            ICompositionElement element = definition.ToElement();
+            return CompositionError.Create(
+                CompositionErrorId.ImportEngine_PartCannotGetExportedValue,
+                element,
+                innerException,
+                Strings.ImportEngine_PartCannotGetExportedValue,
+                element.DisplayName,
+                part.ToElement().DisplayName);
+        }
+
+        public static CompositionError CreatePartCycle(ComposablePart part)
+        {
+            Assumes.NotNull(part);
+
+            ICompositionElement element = part.ToElement();
+            return CompositionError.Create(
+                CompositionErrorId.ImportEngine_PartCycle,
+                element,
+                Strings.ImportEngine_PartCycle,
+                element.DisplayName);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExceptionBuilder.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExceptionBuilder.cs
new file mode 100644
index 00000000000..98b53263fd7
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExceptionBuilder.cs
@@ -0,0 +1,95 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Globalization;
+using System.Reflection;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition
+{
+    internal static class ExceptionBuilder
+    {
+        public static Exception CreateDiscoveryException(string messageFormat, params string[] arguments)
+        {
+            // DiscoveryError (Dev10:602872): This should go through the discovery error reporting when 
+            // we add a way to report discovery errors properly.
+            return new InvalidOperationException(Format(messageFormat, arguments));
+        }
+
+        public static ArgumentException CreateContainsNullElement(string parameterName)
+        {
+            Assumes.NotNull(parameterName);
+
+            string message = Format(Strings.Argument_NullElement, parameterName);
+
+            return new ArgumentException(message, parameterName);
+        }
+
+        public static ObjectDisposedException CreateObjectDisposed(object instance)
+        {
+            Assumes.NotNull(instance);
+
+            return new ObjectDisposedException(instance.GetType().ToString());
+        }
+
+        public static NotImplementedException CreateNotOverriddenByDerived(string memberName)
+        {
+            Assumes.NotNullOrEmpty(memberName);
+
+            string message = Format(Strings.NotImplemented_NotOverriddenByDerived, memberName);
+
+            return new NotImplementedException(message);
+        }
+
+        public static ArgumentException CreateExportDefinitionNotOnThisComposablePart(string parameterName)
+        {
+            Assumes.NotNullOrEmpty(parameterName);
+
+            string message = Format(Strings.ExportDefinitionNotOnThisComposablePart, parameterName);
+
+            return new ArgumentException(message, parameterName);
+        }
+
+        public static ArgumentException CreateImportDefinitionNotOnThisComposablePart(string parameterName)
+        {
+            Assumes.NotNullOrEmpty(parameterName);
+
+            string message = Format(Strings.ImportDefinitionNotOnThisComposablePart, parameterName);
+
+            return new ArgumentException(message, parameterName);
+        }
+
+        public static CompositionException CreateCannotGetExportedValue(ComposablePart part, ExportDefinition definition, Exception innerException)
+        {
+            Assumes.NotNull(part, definition, innerException);
+
+            return new CompositionException(
+                ErrorBuilder.CreateCannotGetExportedValue(part, definition, innerException));
+        }
+
+        public static ArgumentException CreateReflectionModelInvalidPartDefinition(string parameterName, Type partDefinitionType)
+        {
+            Assumes.NotNullOrEmpty(parameterName);
+            Assumes.NotNull(partDefinitionType);
+
+            return new ArgumentException(string.Format(CultureInfo.CurrentCulture, Strings.ReflectionModel_InvalidPartDefinition, partDefinitionType), parameterName);
+        }
+
+        public static ArgumentException ExportFactory_TooManyGenericParameters(string typeName)
+        {
+            Assumes.NotNullOrEmpty(typeName);
+
+            string message = Format(Strings.ExportFactory_TooManyGenericParameters, typeName);
+
+            return new ArgumentException(message, typeName);
+        }
+
+        private static string Format(string format, params string[] arguments)
+        {
+            return String.Format(CultureInfo.CurrentCulture, format, arguments);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportAttribute.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportAttribute.cs
new file mode 100644
index 00000000000..ccd88134d8a
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportAttribute.cs
@@ -0,0 +1,144 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Specifies that a type, property, field, or method provides a particular export.
+    /// </summary>
+    [SuppressMessage("Microsoft.Performance", "CA1813:AvoidUnsealedAttributes")]
+    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Field | AttributeTargets.Property | AttributeTargets.Method, 
+                    AllowMultiple = true, Inherited = false)]
+    public class ExportAttribute : Attribute
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ExportAttribute"/> class, exporting the
+        ///     type or member marked with this attribute under the default contract name.
+        /// </summary>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the type of the 
+        ///         property or field, or the type itself, that is marked with this attribute. 
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public ExportAttribute()
+            : this((string)null, (Type)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ExportAttribute"/> class, exporting the
+        ///     type or member marked with this attribute under a contract name derived from the 
+        ///     specified type.
+        /// </summary>
+        /// <param name="contractType">
+        ///     A <see cref="Type"/> of which to derive the contract name to export the type or 
+        ///     member marked with this attribute, under; or <see langword="null"/> to use the 
+        ///     default contract name.
+        /// </param>
+        /// <remarks>
+        ///     <para>
+        ///         The contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on 
+        ///         <paramref name="contractType"/>.
+        ///     </para>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the type of the 
+        ///         property or field, or the type itself, that is marked with this attribute. 
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public ExportAttribute(Type contractType) 
+            : this((string)null, contractType)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ExportAttribute"/> class, exporting the
+        ///     type or member marked with this attribute under the specified contract name.
+        /// </summary>
+        /// <param name="contractName">
+        ///      A <see cref="String"/> containing the contract name to export the type or member 
+        ///      marked with this attribute, under; or <see langword="null"/> or an empty string 
+        ///      ("") to use the default contract name.
+        /// </param>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the property or field 
+        ///         type, or the type itself that this is marked with this attribute. 
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public ExportAttribute(string contractName)
+            : this(contractName, (Type)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ExportAttribute"/> class, exporting the
+        ///     type or member marked with this attribute under the specified contract name.
+        /// </summary>
+        /// <param name="contractName">
+        ///      A <see cref="String"/> containing the contract name to export the type or member 
+        ///      marked with this attribute, under; or <see langword="null"/> or an empty string 
+        ///      ("") to use the default contract name.
+        /// </param>
+        /// <param name="contractType">
+        ///     A <see cref="Type"/> of which to derive the contract name to export the type or 
+        ///     member marked with this attribute, under; or <see langword="null"/> to use the 
+        ///     default contract name.
+        /// </param>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the property or field 
+        ///         type, or the type itself that this is marked with this attribute. 
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public ExportAttribute(string contractName, Type contractType)
+        {
+            this.ContractName = contractName;
+            this.ContractType = contractType;
+        }
+
+        /// <summary>
+        ///     Gets the contract name to export the type or member under.
+        /// </summary>
+        /// <value>
+        ///      A <see cref="String"/> containing the contract name to export the type or member 
+        ///      marked with this attribute, under. The default value is an empty string ("").
+        /// </value>
+        public string ContractName { get; private set; }
+
+        /// <summary>
+        ///     Get the contract type that is exported by the member that this attribute is attached to.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="Type"/> of the export that is be provided. The default value is
+        ///     <see langword="null"/> which means that the type will be obtained by looking at the type on
+        ///     the member that this export is attached to. 
+        /// </value>
+        public Type ContractType { get; private set; }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportCardinalityCheckResult.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportCardinalityCheckResult.cs
new file mode 100644
index 00000000000..566726cbbcd
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportCardinalityCheckResult.cs
@@ -0,0 +1,14 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+
+namespace System.ComponentModel.Composition
+{
+    internal enum ExportCardinalityCheckResult : int
+    {
+        Match,
+        NoExports,
+        TooManyExports
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportFactoryOfT.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportFactoryOfT.cs
new file mode 100644
index 00000000000..8d72c5df760
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportFactoryOfT.cs
@@ -0,0 +1,41 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using Microsoft.Internal;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition
+{
+    public class ExportFactory<T>
+    {
+        private Func<Tuple<T, Action>> _exportLifetimeContextCreator;
+
+        public ExportFactory(Func<Tuple<T, Action>> exportLifetimeContextCreator)
+        {
+            if (exportLifetimeContextCreator == null)
+            {
+                throw new ArgumentNullException("exportLifetimeContextCreator");
+            }
+
+            this._exportLifetimeContextCreator = exportLifetimeContextCreator;
+        }
+
+        public ExportLifetimeContext<T> CreateExport()
+        {
+            Tuple<T, Action> untypedLifetimeContext = this._exportLifetimeContextCreator.Invoke();
+            return new ExportLifetimeContext<T>(untypedLifetimeContext.Item1, untypedLifetimeContext.Item2);
+        }
+
+        internal bool IncludeInScopedCatalog(ComposablePartDefinition composablePartDefinition)
+        {
+            return this.OnFilterScopedCatalog(composablePartDefinition);
+        }
+
+        protected virtual bool OnFilterScopedCatalog(ComposablePartDefinition composablePartDefinition)
+        {
+            return true;
+        }
+
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportFactoryOfTTMetadata.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportFactoryOfTTMetadata.cs
new file mode 100644
index 00000000000..4569a3d5198
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportFactoryOfTTMetadata.cs
@@ -0,0 +1,25 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition
+{
+    public class ExportFactory<T, TMetadata> : ExportFactory<T>
+    {
+        private readonly TMetadata _metadata;
+
+        public ExportFactory(Func<Tuple<T, Action>> exportLifetimeContextCreator, TMetadata metadata)
+            : base(exportLifetimeContextCreator)
+        {
+            this._metadata = metadata;
+        }
+
+        public TMetadata Metadata
+        {
+            get { return this._metadata; }
+        }
+    }
+}
+
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportLifetimeContextOfT.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportLifetimeContextOfT.cs
new file mode 100644
index 00000000000..ba239328a61
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportLifetimeContextOfT.cs
@@ -0,0 +1,38 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Primitives;
+using System.Linq;
+
+namespace System.ComponentModel.Composition
+{
+    public sealed class ExportLifetimeContext<T> : IDisposable
+    {
+        private readonly T _value;
+        private readonly Action _disposeAction;
+
+        public ExportLifetimeContext(T value, Action disposeAction)
+        {
+            this._value = value;
+            this._disposeAction = disposeAction;
+        }
+
+        public T Value
+        {
+            get
+            {
+                return this._value;
+            }
+        }
+
+        public void Dispose()
+        {
+            if (this._disposeAction != null)
+            {
+                this._disposeAction.Invoke();
+            }
+        }
+    }
+}
+
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportMetadataAttribute.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportMetadataAttribute.cs
new file mode 100644
index 00000000000..1663690eae9
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportMetadataAttribute.cs
@@ -0,0 +1,65 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Specifies metadata for a type, property, field, or method marked with the
+    ///     <see cref="ExportAttribute"/>.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Interface | AttributeTargets.Property | AttributeTargets.Method | AttributeTargets.Field, 
+                    AllowMultiple = true, Inherited = false)]
+    public sealed class ExportMetadataAttribute : Attribute
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ExportMetadataAttribute"/> with the 
+        ///     specified name and metadata value.
+        /// </summary>
+        /// <param name="name">
+        ///     A <see cref="String"/> containing the name of the metadata value; or 
+        ///     <see langword="null"/> to set the <see cref="Name"/> property to an empty 
+        ///     string ("").
+        /// </param>
+        /// <param name="value">
+        ///     An <see cref="object"/> containing the metadata value. This can be 
+        ///     <see langword="null"/>.
+        /// </param>
+        public ExportMetadataAttribute(string name, object value)
+        {
+            this.Name = name ?? string.Empty;
+            this.Value = value;
+        }
+
+        /// <summary>
+        ///     Gets the name of the metadata value.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="String"/> containing the name of the metadata value.
+        /// </value>
+        public string Name
+        {
+            get;
+            private set;
+        }
+
+        /// <summary>
+        ///     Gets the metadata value.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="object"/> containing the metadata value.
+        /// </value>
+        public object Value
+        {
+            get;
+            private set;
+        }
+
+        public bool IsMultiple
+        {
+            get;
+            set;
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportServices.DisposableLazy.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportServices.DisposableLazy.cs
new file mode 100644
index 00000000000..ddf280e8cfe
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportServices.DisposableLazy.cs
@@ -0,0 +1,51 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Primitives;
+using System.Globalization;
+using Microsoft.Internal;
+using System.Threading;
+using System.Collections.Generic;
+
+namespace System.ComponentModel.Composition
+{
+    partial class ExportServices
+    {
+        private sealed class DisposableLazy<T, TMetadataView> : Lazy<T, TMetadataView>, IDisposable
+        {
+            private IDisposable _disposable; 
+
+            public DisposableLazy(Func<T> valueFactory, TMetadataView metadataView, IDisposable disposable, LazyThreadSafetyMode mode)
+                : base(valueFactory, metadataView, mode)
+            {
+                Assumes.NotNull(disposable);
+
+                this._disposable = disposable;
+            }
+
+            void IDisposable.Dispose()
+            {
+                this._disposable.Dispose();
+            }
+        }
+
+        private sealed class DisposableLazy<T> : Lazy<T>, IDisposable
+        {
+            private IDisposable _disposable;
+
+            public DisposableLazy(Func<T> valueFactory, IDisposable disposable, LazyThreadSafetyMode mode)
+                : base(valueFactory, mode)
+            {
+                Assumes.NotNull(disposable);
+
+                this._disposable = disposable;
+            }
+
+            void IDisposable.Dispose()
+            {
+                this._disposable.Dispose();
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportServices.cs
new file mode 100644
index 00000000000..2d093d28828
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ExportServices.cs
@@ -0,0 +1,189 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Linq;
+using System.Reflection;
+using System.Threading;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition
+{
+    // Provides helpers for creating and dealing with Exports
+    internal static partial class ExportServices
+    {
+        private static readonly MethodInfo _createStronglyTypedLazyOfTM = typeof(ExportServices).GetMethod("CreateStronglyTypedLazyOfTM", BindingFlags.NonPublic | BindingFlags.Static);
+        private static readonly MethodInfo _createStronglyTypedLazyOfT = typeof(ExportServices).GetMethod("CreateStronglyTypedLazyOfT", BindingFlags.NonPublic | BindingFlags.Static);
+        private static readonly MethodInfo _createSemiStronglyTypedLazy = typeof(ExportServices).GetMethod("CreateSemiStronglyTypedLazy", BindingFlags.NonPublic | BindingFlags.Static);
+
+        internal static readonly Type DefaultMetadataViewType = typeof(IDictionary<string, object>);
+        internal static readonly Type DefaultExportedValueType = typeof(object);
+
+        internal static bool IsDefaultMetadataViewType(Type metadataViewType)
+        {
+            Assumes.NotNull(metadataViewType);
+
+            // Consider all types that IDictionary<string, object> derives from, such
+            // as ICollection<KeyValuePair<TKey, TValue>>, IEnumerable<KeyValuePair<TKey, TValue>> 
+            // and IEnumerable, as default metadata view
+            return metadataViewType.IsAssignableFrom(DefaultMetadataViewType);
+        }
+
+        internal static bool IsDictionaryConstructorViewType(Type metadataViewType)
+        {
+            Assumes.NotNull(metadataViewType);
+
+            // Does the view type have a constructor that is a Dictionary<string, object>
+            return metadataViewType.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic,
+                                                    Type.DefaultBinder,
+                                                    new Type[] { typeof(IDictionary<string, object>) },
+                                                    new ParameterModifier[0]) != null;
+        }
+
+        internal static Func<Export, object> CreateStronglyTypedLazyFactory(Type exportType, Type metadataViewType)
+        {
+            MethodInfo genericMethod = null;
+            if (metadataViewType != null)
+            {
+                genericMethod = _createStronglyTypedLazyOfTM.MakeGenericMethod(exportType ?? ExportServices.DefaultExportedValueType, metadataViewType);
+            }
+            else
+            {
+                genericMethod = _createStronglyTypedLazyOfT.MakeGenericMethod(exportType ?? ExportServices.DefaultExportedValueType);
+            }
+            Assumes.NotNull(genericMethod);
+            return (Func<Export, object>)Delegate.CreateDelegate(typeof(Func<Export, object>), genericMethod);
+        }
+
+        internal static Func<Export, Lazy<object, object>> CreateSemiStronglyTypedLazyFactory(Type exportType, Type metadataViewType)
+        {
+            MethodInfo genericMethod = _createSemiStronglyTypedLazy.MakeGenericMethod(
+                exportType ?? ExportServices.DefaultExportedValueType,
+                metadataViewType ?? ExportServices.DefaultMetadataViewType);
+            Assumes.NotNull(genericMethod);
+            return (Func<Export, Lazy<object, object>>)Delegate.CreateDelegate(typeof(Func<Export, Lazy<object,object>>), genericMethod);
+        }
+
+        [SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope")]
+        internal static Lazy<T, M> CreateStronglyTypedLazyOfTM<T, M>(Export export)
+        {
+            IDisposable disposable = export as IDisposable;
+            if (disposable != null)
+            {
+                return new DisposableLazy<T, M>(
+                    () => ExportServices.GetCastedExportedValue<T>(export),
+                    AttributedModelServices.GetMetadataView<M>(export.Metadata),
+                    disposable,
+                    LazyThreadSafetyMode.PublicationOnly);
+            }
+            else
+            {
+                return new Lazy<T, M>(
+                    () => ExportServices.GetCastedExportedValue<T>(export),
+                    AttributedModelServices.GetMetadataView<M>(export.Metadata),
+                    LazyThreadSafetyMode.PublicationOnly);
+            }
+        }
+
+        [SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope")]
+        internal static Lazy<T> CreateStronglyTypedLazyOfT<T>(Export export)
+        {
+            IDisposable disposable = export as IDisposable;
+            if (disposable != null)
+            {
+                return new DisposableLazy<T>(
+                    () => ExportServices.GetCastedExportedValue<T>(export),
+                    disposable,
+                    LazyThreadSafetyMode.PublicationOnly);
+            }
+            else
+            {
+                return new Lazy<T>(() => ExportServices.GetCastedExportedValue<T>(export), LazyThreadSafetyMode.PublicationOnly);
+
+            }
+        }
+
+        [SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope")]
+        internal static Lazy<object, object> CreateSemiStronglyTypedLazy<T, M>(Export export)
+        {
+            IDisposable disposable = export as IDisposable;
+            if (disposable != null)
+            {
+                return new DisposableLazy<object, object>(
+                    () => ExportServices.GetCastedExportedValue<T>(export),
+                    AttributedModelServices.GetMetadataView<M>(export.Metadata),
+                    disposable,
+                    LazyThreadSafetyMode.PublicationOnly);
+            }
+            else
+            {
+                return new Lazy<object, object>(
+                    () => ExportServices.GetCastedExportedValue<T>(export),
+                    AttributedModelServices.GetMetadataView<M>(export.Metadata),
+                    LazyThreadSafetyMode.PublicationOnly);
+            }
+        }
+
+        internal static T GetCastedExportedValue<T>(Export export)
+        {
+            return CastExportedValue<T>(export.ToElement(), export.Value);
+        }
+
+        internal static T CastExportedValue<T>(ICompositionElement element, object exportedValue)
+        {
+            object typedExportedValue = null;
+
+            bool succeeded = ContractServices.TryCast(typeof(T), exportedValue, out typedExportedValue);
+            if (!succeeded)
+            {
+                throw new CompositionContractMismatchException(string.Format(CultureInfo.CurrentCulture,
+                    Strings.ContractMismatch_ExportedValueCannotBeCastToT,
+                    element.DisplayName,
+                    typeof(T)));
+            }
+
+            return (T)typedExportedValue;
+        }
+
+        internal static ExportCardinalityCheckResult CheckCardinality<T>(ImportDefinition definition, IEnumerable<T> enumerable)
+        {
+            EnumerableCardinality actualCardinality = (enumerable != null) ? enumerable.GetCardinality() : EnumerableCardinality.Zero;
+
+            return MatchCardinality(actualCardinality, definition.Cardinality);
+        }
+
+
+        private static ExportCardinalityCheckResult MatchCardinality(EnumerableCardinality actualCardinality, ImportCardinality importCardinality)
+        {
+            switch (actualCardinality)
+            {
+                case EnumerableCardinality.Zero:
+                    if (importCardinality == ImportCardinality.ExactlyOne)
+                    {
+                        return ExportCardinalityCheckResult.NoExports;
+                    }
+                    break;
+
+                case EnumerableCardinality.TwoOrMore:
+                    if (importCardinality.IsAtMostOne())
+                    {
+                        return ExportCardinalityCheckResult.TooManyExports;
+                    }
+                    break;
+
+                default:
+                    Assumes.IsTrue(actualCardinality == EnumerableCardinality.One);
+                    break;
+
+            }
+
+            return ExportCardinalityCheckResult.Match;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AggregateCatalog.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AggregateCatalog.cs
new file mode 100644
index 00000000000..2772e9b1ecc
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AggregateCatalog.cs
@@ -0,0 +1,220 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Linq;
+using System.Threading;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    /// <summary>
+    ///     A mutable collection of <see cref="ComposablePartCatalog"/>s.  
+    /// </summary>
+    /// <remarks>
+    ///     This type is thread safe.
+    /// </remarks>
+    public class AggregateCatalog : ComposablePartCatalog, INotifyComposablePartCatalogChanged
+    {
+        private ComposablePartCatalogCollection _catalogs = null;
+        private volatile int _isDisposed = 0;
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="AggregateCatalog"/> class.
+        /// </summary>
+        public AggregateCatalog()
+            : this((IEnumerable<ComposablePartCatalog>)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="AggregateCatalog"/> class 
+        ///     with the specified catalogs.
+        /// </summary>
+        /// <param name="catalogs">
+        ///     An <see cref="Array"/> of <see cref="ComposablePartCatalog"/> objects to add to the 
+        ///     <see cref="AggregateCatalog"/>.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="catalogs"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="catalogs"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        public AggregateCatalog(params ComposablePartCatalog[] catalogs)
+            : this((IEnumerable<ComposablePartCatalog>)catalogs)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="AggregateCatalog"/> class
+        ///     with the specified catalogs.
+        /// </summary>
+        /// <param name="catalogs">
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="ComposablePartCatalog"/> objects to add
+        ///     to the <see cref="AggregateCatalog"/>; or <see langword="null"/> to 
+        ///     create an <see cref="AggregateCatalog"/> that is empty.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="catalogs"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        public AggregateCatalog(IEnumerable<ComposablePartCatalog> catalogs)
+        {
+            Requires.NullOrNotNullElements(catalogs, "catalogs");
+
+            this._catalogs = new ComposablePartCatalogCollection(catalogs, this.OnChanged, this.OnChanging);
+        }
+
+        /// <summary>
+        /// Notify when the contents of the Catalog has changed.
+        /// </summary>
+        public event EventHandler<ComposablePartCatalogChangeEventArgs> Changed
+        {
+            add
+            {
+                this._catalogs.Changed += value;
+            }
+            remove
+            {
+                this._catalogs.Changed -= value;
+            }
+        }
+
+        /// <summary>
+        /// Notify when the contents of the Catalog has changing.
+        /// </summary>
+        public event EventHandler<ComposablePartCatalogChangeEventArgs> Changing
+        {
+            add
+            {
+                this._catalogs.Changing += value;
+            }
+            remove
+            {
+                this._catalogs.Changing -= value;
+            }
+        }
+
+        /// <summary>
+        ///     Returns the export definitions that match the constraint defined by the specified definition.
+        /// </summary>
+        /// <param name="definition">
+        ///     The <see cref="ImportDefinition"/> that defines the conditions of the 
+        ///     <see cref="ExportDefinition"/> objects to return.
+        /// </param>
+        /// <returns>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="Tuple{T1, T2}"/> containing the 
+        ///     <see cref="ExportDefinition"/> objects and their associated 
+        ///     <see cref="ComposablePartDefinition"/> for objects that match the constraint defined 
+        ///     by <paramref name="definition"/>.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="definition"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="AggregateCatalog"/> has been disposed of.
+        /// </exception>
+        public override IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>> GetExports(ImportDefinition definition)
+        {
+            this.ThrowIfDisposed();
+
+            Requires.NotNull(definition, "definition");
+
+            // delegate the query to each catalog and merge the results.
+            var exports = new List<Tuple<ComposablePartDefinition, ExportDefinition>>();
+            foreach (var catalog in this._catalogs)
+            {
+                foreach (var export in catalog.GetExports(definition))
+                {
+                    exports.Add(export);
+                }
+            }
+            return exports;
+        }
+
+        /// <summary>
+        ///     Gets the underlying catalogs of the catalog.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="ICollection{T}"/> of underlying <see cref="ComposablePartCatalog"/> objects
+        ///     of the <see cref="AggregateCatalog"/>.
+        /// </value>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="AggregateCatalog"/> has been disposed of.
+        /// </exception>
+        public ICollection<ComposablePartCatalog> Catalogs
+        {
+            get
+            {
+                this.ThrowIfDisposed();
+                Contract.Ensures(Contract.Result<ICollection<ComposablePartCatalog>>() != null);
+
+                return this._catalogs;
+            }
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            try
+            {
+                if (disposing)
+                {
+                    // NOTE : According to http://msdn.microsoft.com/en-us/library/4bw5ewxy.aspx, the warning is bogus when used with Interlocked API.
+#pragma warning disable 420
+                    if (Interlocked.CompareExchange(ref this._isDisposed, 1, 0) == 0)
+#pragma warning restore 420
+                    {
+                        this._catalogs.Dispose();
+                    }
+                }
+            }
+            finally
+            {
+                base.Dispose(disposing);
+            }
+        }
+
+        public override IEnumerator<ComposablePartDefinition> GetEnumerator()
+        {
+            return this._catalogs.SelectMany(catalog => catalog).GetEnumerator();
+        }
+
+        /// <summary>
+        ///     Raises the <see cref="INotifyComposablePartCatalogChanged.Changed"/> event.
+        /// </summary>
+        /// <param name="e">
+        ///     An <see cref="ComposablePartCatalogChangeEventArgs"/> containing the data for the event.
+        /// </param>
+        protected virtual void OnChanged(ComposablePartCatalogChangeEventArgs e)
+        {
+            this._catalogs.OnChanged(this, e);
+        }
+
+        /// <summary>
+        ///     Raises the <see cref="INotifyComposablePartCatalogChanged.Changing"/> event.
+        /// </summary>
+        /// <param name="e">
+        ///     An <see cref="ComposablePartCatalogChangeEventArgs"/> containing the data for the event.
+        /// </param>
+        protected virtual void OnChanging(ComposablePartCatalogChangeEventArgs e)
+        {
+            this._catalogs.OnChanging(this, e);
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed == 1)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AggregateExportProvider.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AggregateExportProvider.cs
new file mode 100644
index 00000000000..1a12153514b
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AggregateExportProvider.cs
@@ -0,0 +1,235 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Linq;
+using System.Threading;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public class AggregateExportProvider : ExportProvider , IDisposable
+    {
+        private readonly ReadOnlyCollection<ExportProvider> _readOnlyProviders;
+        private readonly ExportProvider[] _providers;
+        private volatile int _isDisposed = 0;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="AggregateExportProvider"/> class.
+        /// </summary>
+        /// <param name="providers">The prioritized list of export providers.</param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="providers"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        /// <remarks>
+        ///     <para>
+        ///         The <see cref="AggregateExportProvider"/> will consult the providers in the order they have been specfied when 
+        ///         executing <see cref="ExportProvider.GetExports(ImportDefinition,AtomicComposition)"/>. 
+        ///     </para>
+        ///     <para>
+        ///         The <see cref="AggregateExportProvider"/> does not take ownership of the specified providers. 
+        ///         That is, it will not try to dispose of any of them when it gets disposed.
+        ///     </para>
+        /// </remarks>
+        public AggregateExportProvider(params ExportProvider[] providers) 
+        {
+            // NOTE : we optimize for the array case here, because the collection of providers is typically tiny
+            // Arrays are much more compact to store and much faster to create and enumerate
+            ExportProvider[] copiedProviders = null;
+            if (providers != null)
+            {
+                copiedProviders = new ExportProvider[providers.Length];
+                for (int i = 0; i < providers.Length; i++)
+                {
+                    ExportProvider provider = providers[i];
+                    if (provider == null)
+                    {
+                        throw ExceptionBuilder.CreateContainsNullElement("providers");
+                    }
+
+                    copiedProviders[i] = provider;
+
+                    provider.ExportsChanged += this.OnExportChangedInternal;
+                    provider.ExportsChanging += this.OnExportChangingInternal;
+                }
+            }
+            else
+            {
+                copiedProviders = new ExportProvider[] { };
+            }
+
+            this._providers = copiedProviders;
+            this._readOnlyProviders = new ReadOnlyCollection<ExportProvider>(this._providers);
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="AggregateExportProvider"/> class.
+        /// </summary>
+        /// <param name="providers">The prioritized list of export providers. The providers are consulted in order in which they are supplied.</param>
+        /// <remarks>
+        ///     <para>
+        ///         The <see cref="AggregateExportProvider"/> will consult the providers in the order they have been specfied when 
+        ///         executing <see cref="ExportProvider.GetExports(ImportDefinition,AtomicComposition)"/>. 
+        ///     </para>
+        ///     <para>
+        ///         The <see cref="AggregateExportProvider"/> does not take ownership of the specified providers. 
+        ///         That is, it will not try to dispose of any of them when it gets disposed.
+        ///     </para>
+        /// </remarks>
+        public AggregateExportProvider(IEnumerable<ExportProvider> providers)
+            : this((providers!= null) ? providers.AsArray() : null)
+        {
+        }
+
+        /// <summary>
+        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
+        /// </summary>
+        public void Dispose()
+        {
+            this.Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        /// <summary>
+        /// Releases unmanaged and - optionally - managed resources
+        /// </summary>
+        /// <param name="disposing"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
+        protected virtual void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                // NOTE : According to http://msdn.microsoft.com/en-us/library/4bw5ewxy.aspx, the warning is bogus when used with Interlocked API.
+#pragma warning disable 420
+                if (Interlocked.CompareExchange(ref this._isDisposed, 1, 0) == 0)
+#pragma warning restore 420
+                {
+                    foreach (ExportProvider provider in this._providers)
+                    {
+                        provider.ExportsChanged -= this.OnExportChangedInternal;
+                        provider.ExportsChanging -= this.OnExportChangingInternal;
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        ///     Gets the export providers which the aggregate export provider aggregates.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="ReadOnlyCollection{T}"/> of <see cref="ExportProvider"/> objects
+        ///     which the <see cref="AggregateExportProvider"/> aggregates.
+        /// </value>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="AggregateExportProvider"/> has been disposed of.
+        /// </exception>
+        public ReadOnlyCollection<ExportProvider> Providers
+        {
+            get
+            {
+                this.ThrowIfDisposed();
+                Contract.Ensures(Contract.Result<ReadOnlyCollection<ExportProvider>>() != null);
+
+                return this._readOnlyProviders;
+            }
+        }
+
+        /// <summary>
+        /// Returns all exports that match the conditions of the specified import.
+        /// </summary>
+        /// <param name="definition">The <see cref="ImportDefinition"/> that defines the conditions of the
+        /// <see cref="Export"/> to get.</param>
+        /// <returns></returns>
+        /// <result>
+        /// An <see cref="IEnumerable{T}"/> of <see cref="Export"/> objects that match
+        /// the conditions defined by <see cref="ImportDefinition"/>, if found; otherwise, an
+        /// empty <see cref="IEnumerable{T}"/>.
+        /// </result>
+        /// <remarks>
+        /// 	<note type="inheritinfo">
+        /// The implementers should not treat the cardinality-related mismatches as errors, and are not
+        /// expected to throw exceptions in those cases.
+        /// For instance, if the import requests exactly one export and the provider has no matching exports or more than one,
+        /// it should return an empty <see cref="IEnumerable{T}"/> of <see cref="Export"/>.
+        /// </note>
+        /// </remarks>
+        protected override IEnumerable<Export> GetExportsCore(ImportDefinition definition, AtomicComposition atomicComposition)
+        {
+            this.ThrowIfDisposed();
+
+            if (definition.Cardinality == ImportCardinality.ZeroOrMore)
+            {
+                var exports = new List<Export>();
+                foreach (var provider in this._providers)
+                {
+                    foreach (var export in provider.GetExports(definition, atomicComposition))
+                    {
+                        exports.Add(export);
+                    }
+                }
+                return exports;
+            }
+            else
+            {
+                IEnumerable<Export> allExports = null;
+
+                // if asked for "one or less", the prioriry is at play - the first provider that agrees to return the value 
+                // which best complies with the request, wins.
+                foreach (ExportProvider provider in this._providers)
+                {
+                    IEnumerable<Export> exports;
+                    bool cardinalityCheckResult = provider.TryGetExports(definition, atomicComposition, out exports);
+                    bool anyExports = exports.FastAny();
+                    if (cardinalityCheckResult && anyExports)
+                    {
+                        // NOTE : if the provider returned nothing, we need to proceed, even if it indicated that the
+                        // cardinality is correct - when asked for "one or less", the provider might - correctly - 
+                        // return an empty sequence, but we shouldn't be satisfied with that as providers down the list
+                        // might have a value we are interested in.
+                        return exports;
+                    }
+                    else
+                    {
+                        // TODO
+                        // This is a sneaky thing that we do - if in the end no provider returns the exports with the right cardinality
+                        // we simply return the aggregation of all exports they have returned. This way the end result is still not what we want
+                        // but no information is lost.
+                        // WE SHOULD fix this behavior, but this is ONLY possible if we can treat many exports as no exports for the sake of singles
+                        if (anyExports)
+                        {
+                            allExports = (allExports != null) ? allExports.Concat(exports) : exports;
+                        }
+                    }
+                }
+
+                return allExports;
+            }
+        }
+
+        private void OnExportChangedInternal(object sender, ExportsChangeEventArgs e)
+        {
+            this.OnExportsChanged(e);
+        }
+
+        private void OnExportChangingInternal(object sender, ExportsChangeEventArgs e)
+        {
+            this.OnExportsChanging(e);
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed == 1)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ApplicationCatalog.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ApplicationCatalog.cs
new file mode 100644
index 00000000000..f022e2c25d1
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ApplicationCatalog.cs
@@ -0,0 +1,232 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.ComponentModel.Composition.Diagnostics;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Globalization;
+using System.Reflection;
+using System.Threading;
+using Microsoft.Internal;
+using System.IO;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+#if !MEF_FEATURE_INITIALIZATION
+    public partial class ApplicationCatalog : ComposablePartCatalog, ICompositionElement
+    {
+        private bool _isDisposed = false;
+        private volatile AggregateCatalog _innerCatalog = null;
+        private readonly object _thisLock = new object();
+        private ICompositionElement _definitionOrigin = null;
+#if FEATURE_REFLECTIONCONTEXT
+        private ReflectionContext _reflectionContext = null;
+#endif
+
+        public ApplicationCatalog() {}
+
+        public ApplicationCatalog(ICompositionElement definitionOrigin)
+        {
+            Requires.NotNull(definitionOrigin, "definitionOrigin");
+
+            this._definitionOrigin = definitionOrigin;
+        }
+
+#if FEATURE_REFLECTIONCONTEXT
+        public ApplicationCatalog(ReflectionContext reflectionContext)
+        {
+            Requires.NotNull(reflectionContext, "reflectionContext");
+
+            this._reflectionContext = reflectionContext;
+        }
+
+        public ApplicationCatalog(ReflectionContext reflectionContext, ICompositionElement definitionOrigin)
+        {
+            Requires.NotNull(reflectionContext, "reflectionContext");
+            Requires.NotNull(definitionOrigin, "definitionOrigin");
+
+            this._reflectionContext = reflectionContext;
+            this._definitionOrigin = definitionOrigin;
+        }
+#endif
+
+        internal ComposablePartCatalog CreateCatalog(string location, string pattern)
+        {
+#if FEATURE_REFLECTIONCONTEXT
+            if(this._reflectionContext != null)
+            {
+                return (this._definitionOrigin != null)
+                    ? new DirectoryCatalog(location, pattern, this._reflectionContext, this._definitionOrigin)
+                    : new DirectoryCatalog(location, pattern, this._reflectionContext);
+            }
+#endif
+            return (this._definitionOrigin != null)
+                ? new DirectoryCatalog(location, pattern, this._definitionOrigin)
+                : new DirectoryCatalog(location, pattern);
+        }
+
+//  Note:
+//      Creating a catalog does not cause change notifications to propagate, For some reason the DeploymentCatalog did, but that is a bug.
+//      InnerCatalog is delay evaluated, from data supplied at construction time and so does not propagate change notifications
+        private AggregateCatalog InnerCatalog
+        {
+            get
+            {
+                if(this._innerCatalog == null)
+                {
+                    lock(this._thisLock)
+                    {
+                        if(this._innerCatalog == null)
+                        {
+                            var location = AppDomain.CurrentDomain.BaseDirectory;
+                            Assumes.NotNull(location);
+        
+                            var catalogs = new List<ComposablePartCatalog>();
+                            catalogs.Add(CreateCatalog(location, "*.exe"));
+                            catalogs.Add(CreateCatalog(location, "*.dll"));
+        
+                            string relativeSearchPath = AppDomain.CurrentDomain.RelativeSearchPath;
+                            if(!string.IsNullOrEmpty(relativeSearchPath))
+                            {
+                                string[] probingPaths = relativeSearchPath.Split(new char[] {';'}, StringSplitOptions.RemoveEmptyEntries);
+                                foreach(var probingPath in probingPaths)
+                                {
+                                    var path = Path.Combine(location, probingPath);
+                                    if(Directory.Exists(path))
+                                    {
+                                        catalogs.Add(CreateCatalog(path, "*.dll"));
+                                    }
+                                }
+                            }
+                            var innerCatalog = new AggregateCatalog(catalogs);
+                            this._innerCatalog = innerCatalog;
+                        }
+                    }
+                }
+
+                return this._innerCatalog;
+            }
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            try
+            {
+                if (!this._isDisposed)
+                {
+                    IDisposable innerCatalog = null;
+                    lock (this._thisLock)
+                    {
+                        innerCatalog = this._innerCatalog as IDisposable;
+                        this._innerCatalog = null;
+                        this._isDisposed = true;
+                    }
+                    if(innerCatalog != null)
+                    {
+                        innerCatalog.Dispose();
+                    }
+                }
+            }
+            finally
+            {
+                base.Dispose(disposing);
+            }
+        }
+
+        public override IEnumerator<ComposablePartDefinition> GetEnumerator()
+        {
+            this.ThrowIfDisposed();
+
+            return this.InnerCatalog.GetEnumerator();
+        }
+
+        /// <summary>
+        ///     Returns the export definitions that match the constraint defined by the specified definition.
+        /// </summary>
+        /// <param name="definition">
+        ///     The <see cref="ImportDefinition"/> that defines the conditions of the 
+        ///     <see cref="ExportDefinition"/> objects to return.
+        /// </param>
+        /// <returns>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="Tuple{T1, T2}"/> containing the 
+        ///     <see cref="ExportDefinition"/> objects and their associated 
+        ///     <see cref="ComposablePartDefinition"/> for objects that match the constraint defined 
+        ///     by <paramref name="definition"/>.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="definition"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="DirectoryCatalog"/> has been disposed of.
+        /// </exception>
+        public override IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>> GetExports(ImportDefinition definition)
+        {
+            this.ThrowIfDisposed();
+
+            Requires.NotNull(definition, "definition");
+
+            return this.InnerCatalog.GetExports(definition);
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+
+        private string GetDisplayName()
+        {
+            return string.Format(CultureInfo.CurrentCulture,
+                                "{0} (Path=\"{1}\") (PrivateProbingPath=\"{2}\")",   // NOLOC
+                                this.GetType().Name,
+                                AppDomain.CurrentDomain.BaseDirectory, 
+                                AppDomain.CurrentDomain.RelativeSearchPath);
+        }
+
+        /// <summary>
+        ///     Returns a string representation of the directory catalog.
+        /// </summary>
+        /// <returns>
+        ///     A <see cref="String"/> containing the string representation of the <see cref="DirectoryCatalog"/>.
+        /// </returns>
+        public override string ToString()
+        {
+            return GetDisplayName();
+        }
+
+        /// <summary>
+        ///     Gets the display name of the ApplicationCatalog.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="String"/> containing a human-readable display name of the <see cref="ApplicationCatalog"/>.
+        /// </value>
+        [SuppressMessage("Microsoft.Design", "CA1033:InterfaceMethodsShouldBeCallableByChildTypes")]
+        string ICompositionElement.DisplayName
+        {
+            get { return this.GetDisplayName(); }
+        }
+
+        /// <summary>
+        ///     Gets the composition element from which the ApplicationCatalog originated.
+        /// </summary>
+        /// <value>
+        ///     This property always returns <see langword="null"/>.
+        /// </value>
+        [SuppressMessage("Microsoft.Design", "CA1033:InterfaceMethodsShouldBeCallableByChildTypes")]
+        ICompositionElement ICompositionElement.Origin
+        {
+            get { return null; }
+        }
+    }
+#endif //MEF_FEATURE_INITIALIZATION
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AssemblyCatalog.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AssemblyCatalog.cs
new file mode 100644
index 00000000000..a8d5c624099
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AssemblyCatalog.cs
@@ -0,0 +1,602 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Globalization;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Security;
+using System.Threading;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    /// <summary>
+    ///     An immutable ComposablePartCatalog created from a managed code assembly.
+    /// </summary>
+    /// <remarks>
+    ///     This type is thread safe.
+    /// </remarks>
+    [DebuggerTypeProxy(typeof(AssemblyCatalogDebuggerProxy))]
+    public class AssemblyCatalog : ComposablePartCatalog, ICompositionElement
+    {
+        private readonly object _thisLock = new object();
+        private readonly ICompositionElement _definitionOrigin;
+        private volatile Assembly _assembly = null;
+        private volatile ComposablePartCatalog _innerCatalog = null;
+        private int _isDisposed = 0;
+
+#if FEATURE_REFLECTIONCONTEXT
+        private ReflectionContext _reflectionContext = default(ReflectionContext);
+#endif //FEATURE_REFLECTIONCONTEXT
+
+#if FEATURE_REFLECTIONFILEIO
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="AssemblyCatalog"/> class 
+        ///     with the specified code base.
+        /// </summary>
+        /// <param name="codeBase">
+        ///     A <see cref="String"/> containing the code base of the assembly containing the
+        ///     attributed <see cref="Type"/> objects to add to the <see cref="AssemblyCatalog"/>.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="codeBase"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="codeBase"/> is a zero-length string, contains only white space, 
+        ///     or contains one or more invalid characters as defined by <see cref="Path.InvalidPathChars"/>.
+        /// </exception>
+        /// <exception cref="PathTooLongException">
+        ///     The specified path, file name, or both exceed the system-defined maximum length. 
+        /// </exception>
+        /// <exception cref="SecurityException">
+        ///     The caller does not have path discovery permission. 
+        /// </exception>
+        /// <exception cref="FileNotFoundException">
+        ///     <paramref name="codeBase"/> is not found.
+        /// </exception>
+        /// <exception cref="FileLoadException ">
+        ///     <paramref name="codeBase"/> could not be loaded.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="codeBase"/> specified a directory.
+        /// </exception>
+        /// <exception cref="BadImageFormatException">
+        ///     <paramref name="codeBase"/> is not a valid assembly
+        ///     -or- 
+        ///     Version 2.0 or later of the common language runtime is currently loaded 
+        ///     and <paramref name="codeBase"/> was compiled with a later version. 
+        /// </exception>
+        /// <remarks>
+        ///     The assembly referenced by <paramref langword="codeBase"/> is loaded into the Load context.
+        /// </remarks>
+        public AssemblyCatalog(string codeBase)
+        {
+            Requires.NotNullOrEmpty(codeBase, "codeBase");
+
+            InitializeAssemblyCatalog(LoadAssembly(codeBase));
+            this._definitionOrigin = this;
+        }
+#endif //FEATURE_REFLECTIONFILEIO
+
+#if FEATURE_REFLECTIONCONTEXT
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="AssemblyCatalog"/> class 
+        ///     with the specified code base.
+        /// </summary>
+        /// <param name="codeBase">
+        ///     A <see cref="String"/> containing the code base of the assembly containing the
+        ///     attributed <see cref="Type"/> objects to add to the <see cref="AssemblyCatalog"/>.
+        /// </param>
+        /// <param name="reflectionContext">
+        ///     The <see cref="ReflectionContext"/> a context used by the catalog when 
+        ///     interpreting the types to inject attributes into the type definition<see cref="AssemblyCatalog"/>.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="codeBase"/> is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="reflectionContext"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="codeBase"/> is a zero-length string, contains only white space, 
+        ///     or contains one or more invalid characters as defined by <see cref="Path.InvalidPathChars"/>.
+        /// </exception>
+        /// <exception cref="PathTooLongException">
+        ///     The specified path, file name, or both exceed the system-defined maximum length. 
+        /// </exception>
+        /// <exception cref="SecurityException">
+        ///     The caller does not have path discovery permission. 
+        /// </exception>
+        /// <exception cref="FileNotFoundException">
+        ///     <paramref name="codeBase"/> is not found.
+        /// </exception>
+        /// <exception cref="FileLoadException ">
+        ///     <paramref name="codeBase"/> could not be loaded.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="codeBase"/> specified a directory.
+        /// </exception>
+        /// <exception cref="BadImageFormatException">
+        ///     <paramref name="codeBase"/> is not a valid assembly
+        ///     -or- 
+        ///     Version 2.0 or later of the common language runtime is currently loaded 
+        ///     and <paramref name="codeBase"/> was compiled with a later version. 
+        /// </exception>
+        /// <remarks>
+        ///     The assembly referenced by <paramref langword="codeBase"/> is loaded into the Load context.
+        /// </remarks>
+        public AssemblyCatalog(string codeBase, ReflectionContext reflectionContext)
+        {
+            Requires.NotNullOrEmpty(codeBase, "codeBase");
+            Requires.NotNull(reflectionContext, "reflectionContext");
+
+            InitializeAssemblyCatalog(LoadAssembly(codeBase));
+            this._reflectionContext = reflectionContext;
+            this._definitionOrigin = this;
+        }
+#endif //FEATURE_REFLECTIONCONTEXT
+
+#if FEATURE_REFLECTIONFILEIO
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="AssemblyCatalog"/> class 
+        ///     with the specified code base.
+        /// </summary>
+        /// <param name="codeBase">
+        ///     A <see cref="String"/> containing the code base of the assembly containing the
+        ///     attributed <see cref="Type"/> objects to add to the <see cref="AssemblyCatalog"/>.
+        /// </param>
+        /// <param name="definitionOrigin">
+        ///     The <see cref="ICompositionElement"/> CompositionElement used by Diagnostics to identify the source for parts.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="codeBase"/> is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="definitionOrigin"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="codeBase"/> is a zero-length string, contains only white space, 
+        ///     or contains one or more invalid characters as defined by <see cref="Path.InvalidPathChars"/>.
+        /// </exception>
+        /// <exception cref="PathTooLongException">
+        ///     The specified path, file name, or both exceed the system-defined maximum length. 
+        /// </exception>
+        /// <exception cref="SecurityException">
+        ///     The caller does not have path discovery permission. 
+        /// </exception>
+        /// <exception cref="FileNotFoundException">
+        ///     <paramref name="codeBase"/> is not found.
+        /// </exception>
+        /// <exception cref="FileLoadException ">
+        ///     <paramref name="codeBase"/> could not be loaded.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="codeBase"/> specified a directory.
+        /// </exception>
+        /// <exception cref="BadImageFormatException">
+        ///     <paramref name="codeBase"/> is not a valid assembly
+        ///     -or- 
+        ///     Version 2.0 or later of the common language runtime is currently loaded 
+        ///     and <paramref name="codeBase"/> was compiled with a later version. 
+        /// </exception>
+        /// <remarks>
+        ///     The assembly referenced by <paramref langword="codeBase"/> is loaded into the Load context.
+        /// </remarks>
+        public AssemblyCatalog(string codeBase, ICompositionElement definitionOrigin)
+        {
+            Requires.NotNullOrEmpty(codeBase, "codeBase");
+            Requires.NotNull(definitionOrigin, "definitionOrigin");
+
+            InitializeAssemblyCatalog(LoadAssembly(codeBase));
+            this._definitionOrigin = definitionOrigin;
+        }
+#endif //FEATURE_REFLECTIONFILEIO
+
+#if FEATURE_REFLECTIONFILEIO && FEATURE_REFLECTIONCONTEXT
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="AssemblyCatalog"/> class 
+        ///     with the specified code base.
+        /// </summary>
+        /// <param name="codeBase">
+        ///     A <see cref="String"/> containing the code base of the assembly containing the
+        ///     attributed <see cref="Type"/> objects to add to the <see cref="AssemblyCatalog"/>.
+        /// </param>
+        /// <param name="reflectionContext">
+        ///     The <see cref="ReflectionContext"/> a context used by the catalog when 
+        ///     interpreting the types to inject attributes into the type definition<see cref="AssemblyCatalog"/>.
+        /// </param>
+        /// <param name="definitionOrigin">
+        ///     The <see cref="ICompositionElement"/> CompositionElement used by Diagnostics to identify the source for parts.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="codeBase"/> is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="reflectionContext"/> is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="definitionOrigin"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="codeBase"/> is a zero-length string, contains only white space, 
+        ///     or contains one or more invalid characters as defined by <see cref="Path.InvalidPathChars"/>.
+        /// </exception>
+        /// <exception cref="PathTooLongException">
+        ///     The specified path, file name, or both exceed the system-defined maximum length. 
+        /// </exception>
+        /// <exception cref="SecurityException">
+        ///     The caller does not have path discovery permission. 
+        /// </exception>
+        /// <exception cref="FileNotFoundException">
+        ///     <paramref name="codeBase"/> is not found.
+        /// </exception>
+        /// <exception cref="FileLoadException ">
+        ///     <paramref name="codeBase"/> could not be loaded.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="codeBase"/> specified a directory.
+        /// </exception>
+        /// <exception cref="BadImageFormatException">
+        ///     <paramref name="codeBase"/> is not a valid assembly
+        ///     -or- 
+        ///     Version 2.0 or later of the common language runtime is currently loaded 
+        ///     and <paramref name="codeBase"/> was compiled with a later version. 
+        /// </exception>
+        /// <remarks>
+        ///     The assembly referenced by <paramref langword="codeBase"/> is loaded into the Load context.
+        /// </remarks>
+        public AssemblyCatalog(string codeBase, ReflectionContext reflectionContext, ICompositionElement definitionOrigin)
+        {
+            Requires.NotNullOrEmpty(codeBase, "codeBase");
+            Requires.NotNull(reflectionContext, "reflectionContext");
+            Requires.NotNull(definitionOrigin, "definitionOrigin");
+
+            InitializeAssemblyCatalog(LoadAssembly(codeBase));
+            this._reflectionContext = reflectionContext;
+            this._definitionOrigin = definitionOrigin;
+        }
+#endif //FEATURE_REFLECTIONFILEIO && FEATURE_REFLECTIONCONTEXT
+
+#if FEATURE_REFLECTIONCONTEXT
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="AssemblyCatalog"/> class 
+        ///     with the specified assembly and reflection context.
+        /// </summary>
+        /// <param name="assembly">
+        ///     The <see cref="Assembly"/> containing the attributed <see cref="Type"/> objects to 
+        ///     add to the <see cref="AssemblyCatalog"/>.
+        /// </param>
+        /// <param name="reflectionContext">
+        ///     The <see cref="ReflectionContext"/> a context used by the catalog when 
+        ///     interpreting the types to inject attributes into the type definition.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="assembly"/> is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>    
+        ///     <paramref name="assembly"/> was loaded in the reflection-only context.
+        ///     <para>
+        ///         -or-
+        ///     </para>    
+        ///     <paramref name="reflectionContext"/> is <see langword="null"/>.
+        /// </exception>
+        public AssemblyCatalog(Assembly assembly, ReflectionContext reflectionContext)
+        {
+            Requires.NotNull(assembly, "assembly");
+            Requires.NotNull(reflectionContext, "reflectionContext");
+
+            InitializeAssemblyCatalog(assembly);
+            this._reflectionContext = reflectionContext;
+            this._definitionOrigin = this;
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="AssemblyCatalog"/> class 
+        ///     with the specified assembly, reflectionContext and definitionOrigin.
+        /// </summary>
+        /// <param name="assembly">
+        ///     The <see cref="Assembly"/> containing the attributed <see cref="Type"/> objects to 
+        ///     add to the <see cref="AssemblyCatalog"/>.
+        /// </param>
+        /// <param name="reflectionContext">
+        ///     The <see cref="ReflectionContext"/> a context used by the catalog when 
+        ///     interpreting the types to inject attributes into the type definition.
+        /// </param>
+        /// <param name="definitionOrigin">
+        ///     The <see cref="ICompositionElement"/> CompositionElement used by Diagnostics to identify the source for parts.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="assembly"/> is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>    
+        ///     <paramref name="assembly"/> was loaded in the reflection-only context.
+        ///     <para>
+        ///         -or-
+        ///     </para>    
+        ///     <paramref name="reflectionContext"/> is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>    
+        ///     <paramref name="definitionOrigin"/> is <see langword="null"/>.
+        /// </exception>
+        public AssemblyCatalog(Assembly assembly, ReflectionContext reflectionContext, ICompositionElement definitionOrigin)
+        {
+            Requires.NotNull(assembly, "assembly");
+            Requires.NotNull(reflectionContext, "reflectionContext");
+            Requires.NotNull(definitionOrigin, "definitionOrigin");
+
+            InitializeAssemblyCatalog(assembly);
+            this._reflectionContext = reflectionContext;
+            this._definitionOrigin = definitionOrigin;
+        }
+#endif //FEATURE_REFLECTIONCONTEXT
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="AssemblyCatalog"/> class 
+        ///     with the specified assembly.
+        /// </summary>
+        /// <param name="assembly">
+        ///     The <see cref="Assembly"/> containing the attributed <see cref="Type"/> objects to 
+        ///     add to the <see cref="AssemblyCatalog"/>.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="assembly"/> is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>    
+        ///     <paramref name="assembly"/> was loaded in the reflection-only context.
+        /// </exception>
+        public AssemblyCatalog(Assembly assembly)
+        {
+            Requires.NotNull(assembly, "assembly");
+
+            InitializeAssemblyCatalog(assembly);
+            this._definitionOrigin = this;
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="AssemblyCatalog"/> class 
+        ///     with the specified assembly.
+        /// </summary>
+        /// <param name="assembly">
+        ///     The <see cref="Assembly"/> containing the attributed <see cref="Type"/> objects to 
+        ///     add to the <see cref="AssemblyCatalog"/>.
+        /// </param>
+        /// <param name="definitionOrigin">
+        ///     The <see cref="ICompositionElement"/> CompositionElement used by Diagnostics to identify the source for parts.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="assembly"/> is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>    
+        ///     <paramref name="assembly"/> was loaded in the reflection-only context.
+        ///     <para>
+        ///         -or-
+        ///     </para>    
+        ///     <paramref name="definitionOrigin"/> is <see langword="null"/>.
+        /// </exception>
+        public AssemblyCatalog(Assembly assembly, ICompositionElement definitionOrigin)
+        {
+            Requires.NotNull(assembly, "assembly");
+            Requires.NotNull(definitionOrigin, "definitionOrigin");
+
+            InitializeAssemblyCatalog(assembly);
+            this._definitionOrigin = definitionOrigin;
+        }
+
+        private void InitializeAssemblyCatalog(Assembly assembly)
+        {
+#if FEATURE_REFLECTIONONLY
+            if (assembly.ReflectionOnly)
+            {
+                throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, Strings.Argument_AssemblyReflectionOnly, "assembly"), "assembly");
+            }
+#endif //FEATURE_REFLECTIONONLY
+            this._assembly = assembly;
+        }
+
+        /// <summary>
+        ///     Returns the export definitions that match the constraint defined by the specified definition.
+        /// </summary>
+        /// <param name="definition">
+        ///     The <see cref="ImportDefinition"/> that defines the conditions of the 
+        ///     <see cref="ExportDefinition"/> objects to return.
+        /// </param>
+        /// <returns>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="Tuple{T1, T2}"/> containing the 
+        ///     <see cref="ExportDefinition"/> objects and their associated 
+        ///     <see cref="ComposablePartDefinition"/> for objects that match the constraint defined 
+        ///     by <paramref name="definition"/>.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="definition"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ComposablePartCatalog"/> has been disposed of.
+        /// </exception>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Overriders of this property should never return <see langword="null"/>, if no 
+        ///         <see cref="ExportDefinition"/> match the conditions defined by 
+        ///         <paramref name="definition"/>, return an empty <see cref="IEnumerable{T}"/>.
+        ///     </note>
+        /// </remarks>
+        [SuppressMessage("Microsoft.Contracts", "CC1055", Justification = "Precondition is being validated in the call to inner catalog")]  
+        public override IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>> GetExports(ImportDefinition definition)
+        {
+            return this.InnerCatalog.GetExports(definition);
+        }
+
+        private ComposablePartCatalog InnerCatalog
+        {
+            get
+            {
+                this.ThrowIfDisposed();
+
+                if (this._innerCatalog == null)
+                {
+#if FEATURE_REFLECTIONCONTEXT
+                    var catalogReflectionContextAttribute = this._assembly.GetFirstAttribute<CatalogReflectionContextAttribute>();
+                    var assembly = (catalogReflectionContextAttribute != null) 
+                        ? catalogReflectionContextAttribute.CreateReflectionContext().MapAssembly(this._assembly)
+                        : this._assembly;
+#else
+                    var assembly = this._assembly;
+#endif //FEATURE_REFLECTIONCONTEXT
+                    lock (this._thisLock)
+                    {
+                        if (this._innerCatalog == null)
+                        {
+#if FEATURE_REFLECTIONCONTEXT
+                            var catalog = (this._reflectionContext != null) 
+                                ? new TypeCatalog(assembly.GetTypes(), this._reflectionContext, this._definitionOrigin)
+                                : new TypeCatalog(assembly.GetTypes(), this._definitionOrigin);
+#else
+                            var catalog = new TypeCatalog(assembly.GetTypes(), this._definitionOrigin);
+#endif //FEATURE_REFLECTIONCONTEXT
+                            Thread.MemoryBarrier();
+                            this._innerCatalog = catalog;
+                        }
+                    }
+                }
+                return this._innerCatalog;
+            }
+        }
+
+        /// <summary>
+        ///     Gets the assembly containing the attributed types contained within the assembly
+        ///     catalog.
+        /// </summary>
+        /// <value>
+        ///     The <see cref="Assembly"/> containing the attributed <see cref="Type"/> objects
+        ///     contained within the <see cref="AssemblyCatalog"/>.
+        /// </value>
+        public Assembly Assembly
+        {
+            get 
+            {
+                Contract.Ensures(Contract.Result<Assembly>() != null);
+                
+                return this._assembly; 
+            }
+        }
+
+        /// <summary>
+        ///     Gets the display name of the assembly catalog.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="String"/> containing a human-readable display name of the <see cref="AssemblyCatalog"/>.
+        /// </value>
+        [SuppressMessage("Microsoft.Design", "CA1033:InterfaceMethodsShouldBeCallableByChildTypes")]
+        string ICompositionElement.DisplayName
+        {
+            get { return this.GetDisplayName(); }
+        }
+
+        /// <summary>
+        ///     Gets the composition element from which the assembly catalog originated.
+        /// </summary>
+        /// <value>
+        ///     This property always returns <see langword="null"/>.
+        /// </value>
+        [SuppressMessage("Microsoft.Design", "CA1033:InterfaceMethodsShouldBeCallableByChildTypes")]
+        ICompositionElement ICompositionElement.Origin
+        {
+            get { return null; }
+        }
+
+
+        /// <summary>
+        ///     Returns a string representation of the assembly catalog.
+        /// </summary>
+        /// <returns>
+        ///     A <see cref="String"/> containing the string representation of the <see cref="AssemblyCatalog"/>.
+        /// </returns>
+        public override string ToString()
+        {
+            return this.GetDisplayName();
+        }
+
+
+        protected override void Dispose(bool disposing)
+        {                
+            try
+            {
+                if (Interlocked.CompareExchange(ref this._isDisposed, 1, 0) == 0)
+                {
+                    if (disposing)
+                    {
+                        if (this._innerCatalog != null)
+                        {
+                            this._innerCatalog.Dispose();
+                        }
+                    }
+                }
+            }
+            finally
+            {
+                base.Dispose(disposing);
+            }
+        }
+
+        public override IEnumerator<ComposablePartDefinition> GetEnumerator()
+        {
+            return this.InnerCatalog.GetEnumerator();
+        }
+
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed == 1)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+
+        private string GetDisplayName()
+        {
+            return string.Format(CultureInfo.CurrentCulture,
+                                "{0} (Assembly=\"{1}\")",   // NOLOC
+                                GetType().Name, 
+                                this.Assembly.FullName);
+        }
+
+#if FEATURE_REFLECTIONFILEIO
+        private static Assembly LoadAssembly(string codeBase)
+        {
+            Requires.NotNullOrEmpty(codeBase, "codeBase");
+
+            AssemblyName assemblyName;
+
+            try
+            {
+                assemblyName = AssemblyName.GetAssemblyName(codeBase);
+            }
+            catch (ArgumentException)
+            {
+                assemblyName = new AssemblyName();
+                assemblyName.CodeBase = codeBase;
+            }
+
+            return Assembly.Load(assemblyName);
+        }
+#endif //FEATURE_REFLECTIONFILEIO
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AssemblyCatalogDebuggerProxy.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AssemblyCatalogDebuggerProxy.cs
new file mode 100644
index 00000000000..e8f519852fa
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AssemblyCatalogDebuggerProxy.cs
@@ -0,0 +1,40 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.ObjectModel;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Linq;
+using System.Reflection;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    internal class AssemblyCatalogDebuggerProxy
+    {
+        private readonly AssemblyCatalog _catalog;
+
+        public AssemblyCatalogDebuggerProxy(AssemblyCatalog catalog)
+        {
+            Requires.NotNull(catalog, "catalog");
+
+            this._catalog = catalog;
+        }
+
+        public Assembly Assembly
+        {
+            get { return this._catalog.Assembly; }
+        }
+
+        public ReadOnlyCollection<ComposablePartDefinition> Parts
+        {
+            // NOTE: This shouldn't be cached, so that on every query of
+            // the current value of the underlying catalog is respected.
+            // We use ReadOnlyCollection as arrays do not have the 
+            // appropriate debugger display attributes applied to them.
+            get { return this._catalog.Parts.ToReadOnlyCollection(); }
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AtomicComposition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AtomicComposition.cs
new file mode 100644
index 00000000000..f0a2fa51c4d
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AtomicComposition.cs
@@ -0,0 +1,315 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    /// <summary>
+    /// AtomicComposition provides lightweight atomicCompositional semantics to enable temporary
+    /// state to be managed for a series of nested atomicCompositions.  Each atomicComposition maintains
+    /// queryable state along with a sequence of actions necessary to complete the state when
+    /// the atomicComposition is no longer in danger of being rolled back.  State is completed or
+    /// rolled back when the atomicComposition is disposed, depending on the state of the
+    /// CompleteOnDipose property which defaults to false.  The using(...) pattern in C# is a
+    /// convenient mechanism for defining atomicComposition scopes.
+    /// 
+    /// The least obvious aspects of AtomicComposition deal with nesting.
+    /// 
+    /// Firstly, no complete actions are actually performed until the outermost atomicComposition is
+    /// completed.  Completeting or rolling back nested atomicCompositions serves only to change which
+    /// actions would be completed the outer atomicComposition.
+    /// 
+    /// Secondly, state is added in the form of queries associated with an object key.  The
+    /// key represents a unique object the state is being held on behalf of.  The quieries are
+    /// accessed throught the Query methods which provide automatic chaining to execute queries
+    /// across the target atomicComposition and its inner atomicComposition as appropriate.
+    /// 
+    /// Lastly, when a nested atomicComposition is created for a given outer the outer atomicComposition is locked.
+    /// It remains locked until the inner atomicComposition is disposed or completeed preventing the addition of
+    /// state, actions or other inner atomicCompositions.
+    /// </summary>
+    public class AtomicComposition : IDisposable
+    {
+        private readonly AtomicComposition _outerAtomicComposition;
+        private KeyValuePair<object, object>[] _values;
+        private int _valueCount = 0;
+        private List<Action> _completeActionList;
+        private List<Action> _revertActionList;
+        private bool _isDisposed = false;
+        private bool _isCompleted = false;
+        private bool _containsInnerAtomicComposition = false;
+
+        public AtomicComposition()
+            : this(null)
+        {
+        }
+
+        public AtomicComposition(AtomicComposition outerAtomicComposition)
+        {
+            // Lock the inner atomicComposition so that we can assume nothing changes except on
+            // the innermost scope, and thereby optimize the query path
+            if (outerAtomicComposition != null)
+            {
+                this._outerAtomicComposition = outerAtomicComposition;
+                this._outerAtomicComposition.ContainsInnerAtomicComposition = true;
+            }
+        }
+
+        public void SetValue(object key, object value)
+        {
+            ThrowIfDisposed();
+            ThrowIfCompleted();
+            ThrowIfContainsInnerAtomicComposition();
+
+            Requires.NotNull(key, "key");
+
+            SetValueInternal(key, value);
+        }
+
+        public bool TryGetValue<T>(object key, out T value) 
+        {
+            return TryGetValue(key, false, out value);
+        }
+
+        [SuppressMessage("Microsoft.Design", "CA1021:AvoidOutParameters")]
+        public bool TryGetValue<T>(object key, bool localAtomicCompositionOnly, out T value) 
+        {
+            ThrowIfDisposed();
+            ThrowIfCompleted();
+
+            Requires.NotNull(key, "key");
+
+            return TryGetValueInternal(key, localAtomicCompositionOnly, out value);
+        }
+
+        public void AddCompleteAction(Action completeAction)
+        {
+            ThrowIfDisposed();
+            ThrowIfCompleted();
+            ThrowIfContainsInnerAtomicComposition();
+
+            Requires.NotNull(completeAction, "completeAction");
+
+            if (this._completeActionList == null)
+            {
+                this._completeActionList = new List<Action>();
+            }
+            this._completeActionList.Add(completeAction);
+        }
+
+        public void AddRevertAction(Action revertAction)
+        {
+            ThrowIfDisposed();
+            ThrowIfCompleted();
+            ThrowIfContainsInnerAtomicComposition();
+
+            Requires.NotNull(revertAction, "revertAction");
+
+            if (this._revertActionList == null)
+            {
+                this._revertActionList = new List<Action>();
+            }
+            this._revertActionList.Add(revertAction);
+        }
+
+        public void Complete()
+        {
+            ThrowIfDisposed();
+            ThrowIfCompleted();
+
+            if (this._outerAtomicComposition == null)
+            {   // Execute all the complete actions
+                FinalComplete();
+            }
+            else
+            {   // Copy the actions and state to the outer atomicComposition
+                CopyComplete();
+            }
+
+            this._isCompleted = true;
+        }
+
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        protected virtual void Dispose(bool disposing)
+        {
+            ThrowIfDisposed();
+            this._isDisposed = true;
+
+            if (this._outerAtomicComposition != null)
+            {
+                this._outerAtomicComposition.ContainsInnerAtomicComposition = false;
+            }
+
+            // Revert is always immediate and involves forgetting information and
+            // exceuting any appropriate revert actions
+            if (!this._isCompleted)
+            {
+                if (this._revertActionList != null)
+                {
+                    // Execute the revert actions in reverse order to ensure
+                    // everything incrementally rollsback its state.
+                    for (int i = this._revertActionList.Count - 1; i >= 0; i--)
+                    {
+                        Action action = this._revertActionList[i];
+                        action();
+                    }
+                    this._revertActionList = null;
+                }
+            }
+        }
+
+        private void FinalComplete()
+        {
+            // Completeting the outer most scope is easy, just execute all the actions
+            if (this._completeActionList != null)
+            {
+                foreach (Action action in this._completeActionList)
+                {
+                    action();
+                }
+                this._completeActionList = null;
+            }
+        }
+
+        private void CopyComplete()
+        {
+            Assumes.NotNull(this._outerAtomicComposition);
+
+            this._outerAtomicComposition.ContainsInnerAtomicComposition = false;
+
+            // Inner scopes are much odder, because completeting them means coalescing them into the
+            // outer scope - the complete or revert actions are deferred until the outermost scope completes
+            // or any intermediate rolls back
+            if (this._completeActionList != null)
+            {
+                foreach (Action action in this._completeActionList)
+                {
+                    this._outerAtomicComposition.AddCompleteAction(action);
+                }
+            }
+
+            if (this._revertActionList != null)
+            {
+                foreach (Action action in this._revertActionList)
+                {
+                    this._outerAtomicComposition.AddRevertAction(action);
+                }
+            }
+
+            // We can copy over existing atomicComposition entries because they're either already chained or
+            // overwrite by design and can now be completed or rolled back together
+            for (var index = 0; index < this._valueCount; index++)
+            {
+                this._outerAtomicComposition.SetValueInternal(
+                    this._values[index].Key, this._values[index].Value);
+            }
+        }
+
+        private bool ContainsInnerAtomicComposition
+        {
+            set
+            {
+                if (value == true && this._containsInnerAtomicComposition == true)
+                {
+                    throw new InvalidOperationException(Strings.AtomicComposition_AlreadyNested);
+                }
+                this._containsInnerAtomicComposition = value;
+            }
+        }
+
+        private bool TryGetValueInternal<T>(object key, bool localAtomicCompositionOnly, out T value) 
+        {
+            for (var index = 0; index < this._valueCount; index++)
+            {
+                if (this._values[index].Key == key)
+                {
+                    value = (T)this._values[index].Value;
+                    return true;
+                }
+            }
+
+            // If there's no atomicComposition available then recurse until we hit the outermost
+            // scope, where upon we go ahead and return null
+            if (!localAtomicCompositionOnly && this._outerAtomicComposition != null)
+            {
+                return this._outerAtomicComposition.TryGetValueInternal<T>(key, localAtomicCompositionOnly, out value);
+            }
+
+            value = default(T);
+            return false;
+        }
+
+        private void SetValueInternal(object key, object value)
+        {
+            // Handle overwrites quickly
+            for (var index = 0; index < this._valueCount; index++)
+            {
+                if (this._values[index].Key == key)
+                {
+                    this._values[index] = new KeyValuePair<object,object>(key, value);
+                    return;
+                }
+            }
+
+            // Expand storage when needed
+            if (this._values == null || this._valueCount == this._values.Length)
+            {
+                var newQueries = new KeyValuePair<object, object>[this._valueCount == 0 ? 5 : this._valueCount * 2];
+                if (this._values != null)
+                {
+                    Array.Copy(this._values, newQueries, this._valueCount);
+                }
+                this._values = newQueries;
+            }
+
+            // Store a new entry
+            this._values[_valueCount] = new KeyValuePair<object, object>(key, value);
+            this._valueCount++;
+            return;
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfContainsInnerAtomicComposition()
+        {
+            if (this._containsInnerAtomicComposition)
+            {
+                throw new InvalidOperationException(Strings.AtomicComposition_PartOfAnotherAtomicComposition);
+            }
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfCompleted()
+        {
+            if (this._isCompleted)
+            {
+                throw new InvalidOperationException(Strings.AtomicComposition_AlreadyCompleted);
+            }
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AtomicCompositionExtensions.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AtomicCompositionExtensions.cs
new file mode 100644
index 00000000000..af573295aa7
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/AtomicCompositionExtensions.cs
@@ -0,0 +1,56 @@
+using System;
+using System.Diagnostics;
+using System.Collections.Generic;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    internal static class AtomicCompositionExtensions
+    {
+        internal static T GetValueAllowNull<T>(this AtomicComposition atomicComposition, T defaultResultAndKey) where T : class
+        {
+            Assumes.NotNull(defaultResultAndKey);
+
+            return GetValueAllowNull<T>(atomicComposition, defaultResultAndKey, defaultResultAndKey);
+        }
+
+        internal static T GetValueAllowNull<T>(this AtomicComposition atomicComposition, object key, T defaultResult)
+        {
+            T result;
+            if (atomicComposition != null && atomicComposition.TryGetValue(key, out result))
+            {
+                return result;
+            }
+
+            return defaultResult;
+        }
+
+        internal static void AddRevertActionAllowNull(this AtomicComposition atomicComposition, Action action)
+        {
+            Assumes.NotNull(action);
+
+            if (atomicComposition == null)
+            {
+                action();
+            }
+            else
+            {
+                atomicComposition.AddRevertAction(action);
+            }
+        }
+
+        internal static void AddCompleteActionAllowNull(this AtomicComposition atomicComposition, Action action)
+        {
+            Assumes.NotNull(action);
+
+            if (atomicComposition == null)
+            {
+                action();
+            }
+            else
+            {
+                atomicComposition.AddCompleteAction(action);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.CatalogChangeProxy.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.CatalogChangeProxy.cs
new file mode 100644
index 00000000000..56e4f01db94
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.CatalogChangeProxy.cs
@@ -0,0 +1,64 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Threading;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class CatalogExportProvider : ExportProvider, IDisposable
+    {
+        private class CatalogChangeProxy : ComposablePartCatalog
+        {
+            private ComposablePartCatalog _originalCatalog;
+            private List<ComposablePartDefinition> _addedParts;
+            private HashSet<ComposablePartDefinition> _removedParts;
+
+            public CatalogChangeProxy(ComposablePartCatalog originalCatalog,
+                IEnumerable<ComposablePartDefinition> addedParts,
+                IEnumerable<ComposablePartDefinition> removedParts)
+            {
+                this._originalCatalog = originalCatalog;
+                this._addedParts = new List<ComposablePartDefinition>(addedParts);
+                this._removedParts = new HashSet<ComposablePartDefinition>(removedParts);
+            }
+
+            public override IEnumerator<ComposablePartDefinition> GetEnumerator()
+            {
+                return this._originalCatalog.Concat(this._addedParts).Except(this._removedParts).GetEnumerator();
+            }
+
+            public override IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>> GetExports(
+                ImportDefinition definition)
+            {
+                Requires.NotNull(definition, "definition");
+
+                var originalExports = this._originalCatalog.GetExports(definition);
+                var trimmedExports = originalExports.Where(partAndExport =>
+                    !this._removedParts.Contains(partAndExport.Item1));
+
+                var addedExports = new List<Tuple<ComposablePartDefinition, ExportDefinition>>();
+                foreach (var part in this._addedParts)
+                {
+                    foreach (var export in part.ExportDefinitions)
+                    {
+                        if (definition.IsConstraintSatisfiedBy(export))
+                        {
+                            addedExports.Add(new Tuple<ComposablePartDefinition, ExportDefinition>(part, export));
+                        }
+                    }
+                }
+                return trimmedExports.Concat(addedExports);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.CatalogExport.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.CatalogExport.cs
new file mode 100644
index 00000000000..7214b94d0a4
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.CatalogExport.cs
@@ -0,0 +1,173 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.CodeAnalysis;
+using Microsoft.Internal;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class CatalogExportProvider
+    {
+        private class CatalogExport : Export
+        {
+            protected readonly CatalogExportProvider _catalogExportProvider;
+            protected readonly ComposablePartDefinition _partDefinition;
+            protected readonly ExportDefinition _definition;
+
+            public CatalogExport(CatalogExportProvider catalogExportProvider,
+                ComposablePartDefinition partDefinition, ExportDefinition definition)
+            {
+                this._catalogExportProvider = catalogExportProvider;
+                this._partDefinition = partDefinition;
+                this._definition = definition;
+            }
+
+            public override ExportDefinition Definition
+            {
+                get
+                {
+                    return this._definition;
+                }
+            }
+
+            protected virtual bool IsSharedPart
+            {
+                get
+                {
+                    return true;
+                }
+            }
+
+            protected CatalogPart GetPartCore()
+            {
+                return this._catalogExportProvider.GetComposablePart(this._partDefinition, this.IsSharedPart);
+            }
+
+            protected void ReleasePartCore(CatalogPart part, object value)
+            {
+                this._catalogExportProvider.ReleasePart(value, part, null);
+            }
+
+            protected virtual CatalogPart GetPart()
+            {
+                return this.GetPartCore();
+            }
+
+            protected override object GetExportedValueCore()
+            {
+                return this._catalogExportProvider.GetExportedValue(this.GetPart(), this._definition, this.IsSharedPart);
+            }
+
+            [SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope")]
+            public static CatalogExport CreateExport(CatalogExportProvider catalogExportProvider,
+                ComposablePartDefinition partDefinition, ExportDefinition definition, CreationPolicy importCreationPolicy)
+            {
+                CreationPolicy partPolicy = partDefinition.Metadata.GetValue<CreationPolicy>(CompositionConstants.PartCreationPolicyMetadataName);
+                bool isSharedPart = ShouldUseSharedPart(partPolicy, importCreationPolicy);
+
+                if (isSharedPart)
+                {
+                    return new CatalogExport(catalogExportProvider, partDefinition, definition);
+                }
+                else
+                {
+                    return new NonSharedCatalogExport(catalogExportProvider, partDefinition, definition);
+                }
+            }
+
+            private static bool ShouldUseSharedPart(CreationPolicy partPolicy, CreationPolicy importPolicy)
+            {
+                // Matrix that details which policy to use for a given part to satisfy a given import.
+                //                   Part.Any   Part.Shared  Part.NonShared
+                // Import.Any        Shared     Shared       NonShared
+                // Import.Shared     Shared     Shared       N/A
+                // Import.NonShared  NonShared  N/A          NonShared
+
+                switch (partPolicy)
+                {
+                    case CreationPolicy.Any:
+                        {
+                            if (importPolicy == CreationPolicy.Any ||
+                                importPolicy == CreationPolicy.NewScope ||
+                                importPolicy == CreationPolicy.Shared)
+                            {
+                                return true;
+                            }
+                            return false;
+                        }
+
+                    case CreationPolicy.NonShared:
+                        {
+                            Assumes.IsTrue(importPolicy != CreationPolicy.Shared);
+                            return false;
+                        }
+
+                    default:
+                        {
+                            Assumes.IsTrue(partPolicy == CreationPolicy.Shared);
+                            Assumes.IsTrue(importPolicy != CreationPolicy.NonShared && importPolicy != CreationPolicy.NewScope);
+                            return true;
+                        }
+                }
+            }
+        }
+
+        private sealed class NonSharedCatalogExport : CatalogExport, IDisposable
+        {
+            private CatalogPart _part;
+            private readonly object _lock = new object();
+
+            public NonSharedCatalogExport(CatalogExportProvider catalogExportProvider,
+                ComposablePartDefinition partDefinition, ExportDefinition definition)
+                : base(catalogExportProvider, partDefinition, definition)
+            {
+            }
+
+            protected override CatalogPart GetPart()
+            {
+                // we need to ensure that the part gets created only once, as the export contract requires that the same value be returned on subsequent calls
+                if (this._part == null)
+                {
+                    CatalogPart part = this.GetPartCore();
+
+                    lock (this._lock)
+                    {
+                        if (this._part == null)
+                        {
+                            Thread.MemoryBarrier();
+                            this._part = part;
+                            part = null;
+                        }
+                    }
+
+                    if (part != null)
+                    {
+                        this.ReleasePartCore(part, null);
+                    }
+                }
+
+                return this._part;
+            }
+
+            protected override bool IsSharedPart
+            {
+                get
+                {
+                    return false;
+                }
+            }
+
+            void IDisposable.Dispose()
+            {
+                if (this._part != null)
+                {
+                    this.ReleasePartCore(this._part, this.Value);
+                    this._part = null;
+                }
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.FactoryExport.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.FactoryExport.cs
new file mode 100644
index 00000000000..cf9ea6ef0e5
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.FactoryExport.cs
@@ -0,0 +1,143 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Linq;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class CatalogExportProvider
+    {
+        internal abstract class FactoryExport : Export
+        {
+            private readonly ComposablePartDefinition _partDefinition;
+            private readonly ExportDefinition _exportDefinition;
+            private ExportDefinition _factoryExportDefinition;
+            private FactoryExportPartDefinition _factoryExportPartDefinition;
+
+            public FactoryExport(ComposablePartDefinition partDefinition, ExportDefinition exportDefinition)
+            {
+                this._partDefinition = partDefinition;
+                this._exportDefinition = exportDefinition;
+                this._factoryExportDefinition = new PartCreatorExportDefinition(this._exportDefinition);
+            }
+
+            public override ExportDefinition Definition
+            {
+                get { return this._factoryExportDefinition; }
+            }
+
+            protected override object GetExportedValueCore()
+            {
+                if (this._factoryExportPartDefinition == null)
+                {
+                    this._factoryExportPartDefinition = new FactoryExportPartDefinition(this);
+                }
+                return this._factoryExportPartDefinition;
+            }
+
+            protected ComposablePartDefinition UnderlyingPartDefinition
+            {
+                get
+                {
+                    return this._partDefinition;
+                }
+            }
+
+            protected ExportDefinition UnderlyingExportDefinition
+            {
+                get
+                {
+                    return this._exportDefinition;
+                }
+            }
+
+            public abstract Export CreateExportProduct();
+
+            private class FactoryExportPartDefinition : ComposablePartDefinition
+            {
+                private readonly FactoryExport _FactoryExport;
+
+                public FactoryExportPartDefinition(FactoryExport FactoryExport)
+                {
+                    this._FactoryExport = FactoryExport;
+                }
+
+                public override IEnumerable<ExportDefinition> ExportDefinitions
+                {
+                    get { return new ExportDefinition[] { this._FactoryExport.Definition }; }
+                }
+
+                public override IEnumerable<ImportDefinition> ImportDefinitions
+                {
+                    get { return Enumerable.Empty<ImportDefinition>(); }
+                }
+
+                public ExportDefinition FactoryExportDefinition
+                {
+                    get { return this._FactoryExport.Definition; }
+                }
+
+                public Export CreateProductExport()
+                {
+                    return this._FactoryExport.CreateExportProduct();
+                }
+
+                public override ComposablePart CreatePart()
+                {
+                    return new FactoryExportPart(this);
+                }
+            }
+
+            private sealed class FactoryExportPart : ComposablePart, IDisposable
+            {
+                private readonly FactoryExportPartDefinition _definition;
+                private readonly Export _export;
+
+                public FactoryExportPart(FactoryExportPartDefinition definition)
+                {
+                    this._definition = definition;
+                    this._export = definition.CreateProductExport();
+                }
+
+                public override IEnumerable<ExportDefinition> ExportDefinitions
+                {
+                    get { return this._definition.ExportDefinitions; }
+                }
+
+                public override IEnumerable<ImportDefinition> ImportDefinitions
+                {
+                    get { return this._definition.ImportDefinitions; }
+                }
+
+                public override object GetExportedValue(ExportDefinition definition)
+                {
+                    if (definition != this._definition.FactoryExportDefinition)
+                    {
+                        throw ExceptionBuilder.CreateExportDefinitionNotOnThisComposablePart("definition");
+                    }
+
+                    return this._export.Value;
+                }
+
+                public override void SetImport(ImportDefinition definition, IEnumerable<Export> exports)
+                {
+                    throw ExceptionBuilder.CreateImportDefinitionNotOnThisComposablePart("definition");
+                }
+
+                public void Dispose()
+                {
+                    IDisposable disposable = this._export as IDisposable;
+
+                    if (disposable != null)
+                    {
+                        disposable.Dispose();
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.PartCreatorExport.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.PartCreatorExport.cs
new file mode 100644
index 00000000000..1f5e7bd537a
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.PartCreatorExport.cs
@@ -0,0 +1,30 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Linq;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class CatalogExportProvider
+    {
+        internal class PartCreatorExport : FactoryExport
+        {
+            private readonly CatalogExportProvider _catalogExportProvider;
+
+            public PartCreatorExport(CatalogExportProvider catalogExportProvider, ComposablePartDefinition partDefinition, ExportDefinition exportDefinition) : 
+                base(partDefinition, exportDefinition)
+            {
+                this._catalogExportProvider = catalogExportProvider;
+            }
+
+            public override Export CreateExportProduct()
+            {
+                return new NonSharedCatalogExport(this._catalogExportProvider, this.UnderlyingPartDefinition, this.UnderlyingExportDefinition);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.ScopeFactoryExport.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.ScopeFactoryExport.cs
new file mode 100644
index 00000000000..9267c282066
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.ScopeFactoryExport.cs
@@ -0,0 +1,117 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Linq;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class CatalogExportProvider
+    {
+        internal class ScopeFactoryExport : FactoryExport
+        {
+            private readonly ScopeManager _scopeManager;
+            private readonly CompositionScopeDefinition _catalog;
+
+            internal ScopeFactoryExport(ScopeManager scopeManager, CompositionScopeDefinition catalog, ComposablePartDefinition partDefinition, ExportDefinition exportDefinition) :
+                base(partDefinition, exportDefinition)
+            {
+                this._scopeManager = scopeManager;
+                this._catalog = catalog;
+            }
+
+            public virtual Export CreateExportProduct(Func<ComposablePartDefinition, bool> filter)
+            {
+                return new ScopeCatalogExport(this, filter);
+            }
+
+            public override Export CreateExportProduct()
+            {
+                return new ScopeCatalogExport(this, null);
+            }
+
+            private sealed class ScopeCatalogExport : Export, IDisposable
+            {
+                private readonly ScopeFactoryExport _scopeFactoryExport;
+                private Func<ComposablePartDefinition, bool> _catalogFilter;
+                private CompositionContainer _childContainer;
+                private Export _export;
+                private readonly object _lock = new object();
+
+                public ScopeCatalogExport(ScopeFactoryExport scopeFactoryExport, Func<ComposablePartDefinition, bool> catalogFilter)
+                {
+                    this._scopeFactoryExport = scopeFactoryExport;
+                    this._catalogFilter = catalogFilter;
+                }
+
+                public override ExportDefinition Definition
+                {
+                    get
+                    {
+                        return this._scopeFactoryExport.UnderlyingExportDefinition;
+                    }
+                }
+
+                protected override object GetExportedValueCore()
+                {
+                    if (this._export == null)
+                    {
+                        // Need to create a new scopedefinition that is filtered by the ExportProvider
+                        var filteredScopeDefinition = new CompositionScopeDefinition(
+                            new FilteredCatalog(this._scopeFactoryExport._catalog, this._catalogFilter), 
+                            this._scopeFactoryExport._catalog.Children);
+                        var childContainer = this._scopeFactoryExport._scopeManager.CreateChildContainer(filteredScopeDefinition);
+
+                        var export = childContainer.CatalogExportProvider.CreateExport(this._scopeFactoryExport.UnderlyingPartDefinition, this._scopeFactoryExport.UnderlyingExportDefinition, false, CreationPolicy.Any);
+                        lock (this._lock)
+                        {
+                            if (this._export == null)
+                            {
+                                this._childContainer = childContainer;
+                                Thread.MemoryBarrier();
+                                this._export = export;
+
+                                childContainer = null;
+                                export = null;
+                            }
+                        }
+                        if (childContainer != null)
+                        {
+                            childContainer.Dispose();
+                        }
+                    }
+
+                    return this._export.Value;
+                }
+
+                public void Dispose()
+                {
+                    CompositionContainer childContainer = null;
+                    Export export = null;
+
+                    if (this._export != null)
+                    {
+                        lock (this._lock)
+                        {
+                            export = this._export;
+                            childContainer = this._childContainer;
+
+                            this._childContainer = null;
+                            Thread.MemoryBarrier();
+                            this._export = null;
+                        }
+                    }
+
+                    if(childContainer != null)
+                    {
+                        childContainer.Dispose();
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.ScopeManager.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.ScopeManager.cs
new file mode 100644
index 00000000000..b07a961bca2
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.ScopeManager.cs
@@ -0,0 +1,115 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Linq;
+using System.Text;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class CatalogExportProvider
+    {
+        internal class ScopeManager : ExportProvider
+        {
+            private CompositionScopeDefinition _scopeDefinition;
+            private CatalogExportProvider _catalogExportProvider;
+
+            public ScopeManager(CatalogExportProvider catalogExportProvider, CompositionScopeDefinition scopeDefinition)
+            {
+                Assumes.NotNull(catalogExportProvider);
+                Assumes.NotNull(scopeDefinition);
+
+                this._scopeDefinition = scopeDefinition;
+                this._catalogExportProvider = catalogExportProvider;
+            }
+
+            protected override IEnumerable<Export> GetExportsCore(ImportDefinition definition, AtomicComposition atomicComposition)
+            {
+                List<Export> exports = new List<Export>();
+
+                ImportDefinition queryImport = TranslateImport(definition);
+                if (queryImport == null)
+                {
+                    return exports;
+                }
+
+                // go through the catalogs and see if there's anything there of interest
+                foreach (CompositionScopeDefinition childCatalog in this._scopeDefinition.Children)
+                {
+                    foreach (var partDefinitionAndExportDefinition in childCatalog.GetExportsFromPublicSurface(queryImport))
+                    {
+                        using (var container = this.CreateChildContainer(childCatalog))
+                        {
+                            // We create a nested AtomicComposition() because the container will be Disposed and 
+                            // the RevertActions need to operate before we Dispose the child container
+                            using (var ac = new AtomicComposition(atomicComposition))
+                            {
+                                var childCatalogExportProvider = container.CatalogExportProvider;
+                                if (!childCatalogExportProvider.DetermineRejection(partDefinitionAndExportDefinition.Item1, ac))
+                                {
+                                    exports.Add(this.CreateScopeExport(childCatalog, partDefinitionAndExportDefinition.Item1, partDefinitionAndExportDefinition.Item2));
+                                }
+                            }
+                        }
+                    }
+                }
+
+                return exports;
+            }
+
+            private Export CreateScopeExport(CompositionScopeDefinition childCatalog, ComposablePartDefinition partDefinition, ExportDefinition exportDefinition)
+            {
+                return new ScopeFactoryExport(this, childCatalog, partDefinition, exportDefinition);
+            }
+
+            internal CompositionContainer CreateChildContainer(ComposablePartCatalog childCatalog)
+            {
+                return new CompositionContainer(childCatalog, this._catalogExportProvider._compositionOptions, this._catalogExportProvider._sourceProvider);
+            }
+
+            private static ImportDefinition TranslateImport(ImportDefinition definition)
+            {
+                IPartCreatorImportDefinition factoryDefinition = definition as IPartCreatorImportDefinition;
+                if (factoryDefinition == null)
+                {
+                    return null;
+                }
+
+                // Now we need to make sure that the creation policy is handled correctly
+                // We will always create a new child CatalogEP to satsify the request, so from the perspecitive of the caller, the policy should 
+                // always be NonShared (or Any). From teh perspective of the callee, it's the otehr way around.
+                ContractBasedImportDefinition productImportDefinition = factoryDefinition.ProductImportDefinition;
+                ImportDefinition result = null;
+
+                switch (productImportDefinition.RequiredCreationPolicy)
+                {
+                    case CreationPolicy.NonShared:
+                    case CreationPolicy.NewScope:
+                        {
+                            // we need to recreate the import definition with the policy "Any", so that we can
+                            // pull singletons from the inner CatalogEP. teh "non-sharedness" is achieved through 
+                            // the creation of the new EPs already.
+                            result = new ContractBasedImportDefinition(
+                                productImportDefinition.ContractName,
+                                productImportDefinition.RequiredTypeIdentity,
+                                productImportDefinition.RequiredMetadata,
+                                productImportDefinition.Cardinality,
+                                productImportDefinition.IsRecomposable,
+                                productImportDefinition.IsPrerequisite,
+                                CreationPolicy.Any,
+                                productImportDefinition.Metadata);
+                            break;
+                        }
+                    case CreationPolicy.Any:
+                        {
+                            // "Any" works every time
+                            result = productImportDefinition;
+                            break;
+                        }
+                }
+
+                return result;
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.cs
new file mode 100644
index 00000000000..874bb4f5830
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExportProvider.cs
@@ -0,0 +1,955 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Diagnostics;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Globalization;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Threading;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class CatalogExportProvider : ExportProvider, IDisposable
+    {
+        private class InnerCatalogExportProvider : ExportProvider
+        {
+            Func<ImportDefinition, AtomicComposition, IEnumerable<Export>> _getExportsCore;
+            
+            public InnerCatalogExportProvider(Func<ImportDefinition, AtomicComposition, IEnumerable<Export>> getExportsCore )
+            {
+                this._getExportsCore = getExportsCore;
+            }
+
+            protected override IEnumerable<Export> GetExportsCore(ImportDefinition definition, AtomicComposition atomicComposition)
+            {
+                Assumes.NotNull(this._getExportsCore);
+                return this._getExportsCore(definition, atomicComposition);
+            }
+        }
+
+        private readonly CompositionLock _lock;
+        private Dictionary<ComposablePartDefinition, CatalogPart> _activatedParts = new Dictionary<ComposablePartDefinition, CatalogPart>();
+        private HashSet<ComposablePartDefinition> _rejectedParts = new HashSet<ComposablePartDefinition>();
+        private ConditionalWeakTable<object, List<ComposablePart>> _gcRoots;
+        private HashSet<IDisposable> _partsToDispose = new HashSet<IDisposable>();
+        private ComposablePartCatalog _catalog;
+        private volatile bool _isDisposed = false;
+        private volatile bool _isRunning = false;
+        private ExportProvider _sourceProvider;
+        private ImportEngine _importEngine;
+        private CompositionOptions _compositionOptions;
+        private ExportProvider _innerExportProvider;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CatalogExportProvider"/> class.
+        /// </summary>
+        /// <param name="catalog">
+        ///     The <see cref="ComposablePartCatalog"/> that the <see cref="CatalogExportProvider"/>
+        ///     uses to produce <see cref="Export"/> objects.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="catalog"/> is <see langword="null"/>.
+        /// </exception>
+        public CatalogExportProvider(ComposablePartCatalog catalog)
+            : this(catalog, CompositionOptions.Default)
+        {
+        }
+
+        public CatalogExportProvider(ComposablePartCatalog catalog, bool isThreadSafe)
+            : this(catalog, isThreadSafe ? CompositionOptions.IsThreadSafe : CompositionOptions.Default)
+        {
+        }
+
+        public CatalogExportProvider(ComposablePartCatalog catalog, CompositionOptions compositionOptions)
+        {
+            Requires.NotNull(catalog, "catalog");
+            if (compositionOptions > (CompositionOptions.DisableSilentRejection | CompositionOptions.IsThreadSafe | CompositionOptions.ExportCompositionService))
+            {
+                throw new ArgumentOutOfRangeException("compositionOptions");
+            }
+
+            this._catalog = catalog;
+            this._compositionOptions = compositionOptions;
+            var notifyCatalogChanged = this._catalog as INotifyComposablePartCatalogChanged;
+            if (notifyCatalogChanged != null)
+            {
+                notifyCatalogChanged.Changing += this.OnCatalogChanging;
+            }
+
+            CompositionScopeDefinition scopeDefinition = this._catalog as CompositionScopeDefinition;
+            if (scopeDefinition != null)
+            {
+                this._innerExportProvider = new AggregateExportProvider(new ScopeManager(this, scopeDefinition), new InnerCatalogExportProvider(InternalGetExportsCore));
+            }
+            else
+            {
+                this._innerExportProvider = new InnerCatalogExportProvider(InternalGetExportsCore);
+            }            
+            this._lock = new CompositionLock(compositionOptions.HasFlag(CompositionOptions.IsThreadSafe));
+        }
+
+
+        /// <summary>
+        ///     Gets the composable part catalog that the provider users to 
+        ///     produce exports.
+        /// </summary>
+        /// <value>
+        ///     The <see cref="ComposablePartCatalog"/> that the 
+        ///     <see cref="CatalogExportProvider"/>
+        ///     uses to produce <see cref="Export"/> objects.
+        /// </value>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        public ComposablePartCatalog Catalog
+        {
+            get
+            {
+                ThrowIfDisposed();
+                Contract.Ensures(Contract.Result<ComposablePartCatalog>() != null);
+
+                return this._catalog;
+            }
+        }
+
+        /// <summary>
+        ///     Gets the export provider which provides the provider access to additional
+        ///     exports.
+        /// </summary>
+        /// <value>
+        ///     The <see cref="ExportProvider"/> which provides the 
+        ///     <see cref="CatalogExportProvider"/> access to additional
+        ///     <see cref="Export"/> objects. The default is <see langword="null"/>.
+        /// </value>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="value"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="InvalidOperationException">
+        ///     This property has already been set.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     The methods on the <see cref="CatalogExportProvider"/> 
+        ///     have already been accessed.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CatalogExportProvider"/> has been disposed of.
+        /// </exception>
+        /// <remarks>
+        ///     This property must be set before accessing any methods on the 
+        ///     <see cref="CatalogExportProvider"/>.
+        /// </remarks>
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope", Justification="EnsureCanSet ensures that the property is set only once, Dispose is not required")]
+        public ExportProvider SourceProvider
+        {
+            get
+            {
+                this.ThrowIfDisposed();
+                using (this._lock.LockStateForRead())
+                {
+                    return this._sourceProvider;
+                }
+            }
+            set
+            {
+                this.ThrowIfDisposed();
+
+                Requires.NotNull(value, "value");
+
+                ImportEngine newImportEngine = null;
+                AggregateExportProvider aggregateExportProvider = null;
+                ExportProvider sourceProvider = value;
+
+                bool isThrowing = true;
+                try
+                {
+                    newImportEngine = new ImportEngine(sourceProvider, this._compositionOptions);
+
+                    sourceProvider.ExportsChanging += this.OnExportsChangingInternal;
+
+                    using (this._lock.LockStateForWrite())
+                    {
+                        this.EnsureCanSet(this._sourceProvider);
+
+                        this._sourceProvider = sourceProvider;
+                        this._importEngine = newImportEngine;
+
+                        isThrowing = false;
+                    }
+                }
+                finally
+                {
+                    if (isThrowing)
+                    {
+                        sourceProvider.ExportsChanging -= this.OnExportsChangingInternal;
+                        newImportEngine.Dispose();
+                        if (aggregateExportProvider != null)
+                        {
+                            aggregateExportProvider.Dispose();
+                        }
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Releases unmanaged and - optionally - managed resources
+        /// </summary>
+        public void Dispose()
+        {
+            this.Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        /// <summary>
+        /// Releases unmanaged and - optionally - managed resources
+        /// </summary>
+        /// <param name="disposing"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
+        protected virtual void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                if (!this._isDisposed)
+                {
+                    bool disposeLock = false;
+                    INotifyComposablePartCatalogChanged catalogToUnsubscribeFrom = null;
+                    HashSet<IDisposable> partsToDispose = null;
+                    ImportEngine importEngine = null;
+                    ExportProvider sourceProvider = null;
+                    AggregateExportProvider aggregateExportProvider = null;
+                    try
+                    {
+                        using (this._lock.LockStateForWrite())
+                        {
+                            if (!this._isDisposed)
+                            {
+                                catalogToUnsubscribeFrom = this._catalog as INotifyComposablePartCatalogChanged;
+                                this._catalog = null;
+
+                                aggregateExportProvider = this._innerExportProvider as AggregateExportProvider;
+                                this._innerExportProvider = null;
+
+                                sourceProvider = this._sourceProvider;
+                                this._sourceProvider = null;
+
+                                importEngine = this._importEngine;
+                                this._importEngine = null;
+
+                                partsToDispose = this._partsToDispose;
+                                this._gcRoots = null;
+
+                                disposeLock = true;
+                                this._isDisposed = true;
+                                
+                            }
+                        }
+                    }
+                    finally
+                    {
+                        if (catalogToUnsubscribeFrom != null)
+                        {
+                            catalogToUnsubscribeFrom.Changing -= this.OnCatalogChanging;
+                        }
+
+                        if (aggregateExportProvider != null)
+                        {
+                            aggregateExportProvider.Dispose();
+                        }
+
+                        if (sourceProvider != null)
+                        {
+                            sourceProvider.ExportsChanging -= this.OnExportsChangingInternal;
+                        }
+
+                        if (importEngine != null)
+                        {
+                            importEngine.Dispose();
+                        }
+
+                        if (partsToDispose != null)
+                        {
+                            foreach (var part in partsToDispose)
+                            {
+                                part.Dispose();
+                            }
+                        }
+
+                        if (disposeLock)
+                        {
+                            this._lock.Dispose();
+                        }
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Returns all exports that match the conditions of the specified import.
+        /// </summary>
+        /// <param name="definition">The <see cref="ImportDefinition"/> that defines the conditions of the
+        /// <see cref="Export"/> to get.</param>
+        /// <returns></returns>
+        /// <result>
+        /// An <see cref="IEnumerable{T}"/> of <see cref="Export"/> objects that match
+        /// the conditions defined by <see cref="ImportDefinition"/>, if found; otherwise, an
+        /// empty <see cref="IEnumerable{T}"/>.
+        /// </result>
+        /// <remarks>
+        /// 	<note type="inheritinfo">
+        /// The implementers should not treat the cardinality-related mismatches as errors, and are not
+        /// expected to throw exceptions in those cases.
+        /// For instance, if the import requests exactly one export and the provider has no matching exports or more than one,
+        /// it should return an empty <see cref="IEnumerable{T}"/> of <see cref="Export"/>.
+        /// </note>
+        /// </remarks>
+        protected override IEnumerable<Export> GetExportsCore(ImportDefinition definition, AtomicComposition atomicComposition)
+        {
+            this.ThrowIfDisposed();
+            this.EnsureRunning();
+
+            Assumes.NotNull(this._innerExportProvider);
+
+            IEnumerable<Export> exports;
+            this._innerExportProvider.TryGetExports(definition, atomicComposition, out exports);
+            return exports;
+        }
+
+        private IEnumerable<Export> InternalGetExportsCore(ImportDefinition definition, AtomicComposition atomicComposition)
+        {
+            this.ThrowIfDisposed();
+            this.EnsureRunning();
+            
+            // Use the version of the catalog appropriate to this atomicComposition
+            ComposablePartCatalog currentCatalog = atomicComposition.GetValueAllowNull(this._catalog);
+
+            IPartCreatorImportDefinition partCreatorDefinition = definition as IPartCreatorImportDefinition;
+            bool isExportFactory = false;
+
+            if (partCreatorDefinition != null)
+            {
+                definition = partCreatorDefinition.ProductImportDefinition;
+                isExportFactory = true;
+            }
+
+            CreationPolicy importPolicy = definition.GetRequiredCreationPolicy();
+
+            List<Export> exports = new List<Export>();
+            foreach (var partDefinitionAndExportDefinition in currentCatalog.GetExports(definition))
+            {
+                if (!this.IsRejected(partDefinitionAndExportDefinition.Item1, atomicComposition))
+                {
+                    exports.Add(this.CreateExport(partDefinitionAndExportDefinition.Item1, partDefinitionAndExportDefinition.Item2, isExportFactory, importPolicy));
+                }
+            }
+
+            return exports;
+        }
+
+        private Export CreateExport(ComposablePartDefinition partDefinition, ExportDefinition exportDefinition, bool isExportFactory, CreationPolicy importPolicy)
+        {
+            if (isExportFactory)
+            {
+                return new PartCreatorExport(this,
+                            partDefinition,
+                            exportDefinition);
+            }
+            else
+            {
+                return CatalogExport.CreateExport(this,
+                            partDefinition,
+                            exportDefinition,
+                            importPolicy);
+            }
+        }
+
+
+
+        private void OnExportsChangingInternal(object sender, ExportsChangeEventArgs e)
+        {
+            UpdateRejections(e.AddedExports.Concat(e.RemovedExports), e.AtomicComposition);
+        }
+
+        private static ExportDefinition[] GetExportsFromPartDefinitions(IEnumerable<ComposablePartDefinition> partDefinitions)
+        {
+            List<ExportDefinition> exports = new List<ExportDefinition>();
+
+            foreach (var partDefinition in partDefinitions)
+            {
+                foreach (var export in partDefinition.ExportDefinitions)
+                {
+                    exports.Add(export);
+
+                    // While creating a PartCreatorExportDefinition for every changed definition may not be the most
+                    // efficient way to do this the PartCreatorExportDefinition is very efficient and doesn't do any
+                    // real work unless its metadata is pulled on. If this turns out to be a bottleneck then we
+                    // will need to start tracking all the PartCreator's we hand out and only send those which we 
+                    // have handed out. In fact we could do the same thing for all the Exports if we wished but 
+                    // that requires a cache management which we don't want to do at this point.
+                    exports.Add(new PartCreatorExportDefinition(export));
+                }
+            }
+
+            return exports.ToArray();
+        }
+
+        [SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope")]
+        private void OnCatalogChanging(object sender, ComposablePartCatalogChangeEventArgs e)
+        {
+            using (var atomicComposition = new AtomicComposition(e.AtomicComposition))
+            {
+                // Save the preview catalog to use in place of the original while handling
+                // this event
+                atomicComposition.SetValue(this._catalog,
+                    new CatalogChangeProxy(this._catalog, e.AddedDefinitions, e.RemovedDefinitions));
+
+                IEnumerable<ExportDefinition> addedExports = GetExportsFromPartDefinitions(e.AddedDefinitions);
+                IEnumerable<ExportDefinition> removedExports = GetExportsFromPartDefinitions(e.RemovedDefinitions);
+
+                // Remove any parts based on eliminated definitions (in a atomicComposition-friendly
+                // fashion)
+                foreach (var definition in e.RemovedDefinitions)
+                {
+                    CatalogPart removedPart = null;
+                    bool removed = false;
+
+                    using (this._lock.LockStateForRead())
+                    {
+                        removed = this._activatedParts.TryGetValue(definition, out removedPart);
+                    }
+
+                    if (removed)
+                    {
+                        var capturedDefinition = definition;
+                        this.ReleasePart(null, removedPart, atomicComposition);
+                        atomicComposition.AddCompleteActionAllowNull(() =>
+                        {
+                            using (this._lock.LockStateForWrite())
+                            {
+                                this._activatedParts.Remove(capturedDefinition);
+                            }
+                        });
+                    }
+                }
+
+                UpdateRejections(addedExports.ConcatAllowingNull(removedExports), atomicComposition);
+
+                this.OnExportsChanging(
+                    new ExportsChangeEventArgs(addedExports, removedExports, atomicComposition));
+
+                atomicComposition.AddCompleteAction(() => this.OnExportsChanged(
+                    new ExportsChangeEventArgs(addedExports, removedExports, null)));
+
+                atomicComposition.Complete();
+            }
+        }
+
+        private CatalogPart GetComposablePart(ComposablePartDefinition partDefinition, bool isSharedPart)
+        {
+            this.ThrowIfDisposed();
+            this.EnsureRunning();
+
+            CatalogPart catalogPart = null;
+
+            if (isSharedPart)
+            {
+                catalogPart = this.GetSharedPart(partDefinition);
+            }
+            else
+            {
+                ComposablePart part = partDefinition.CreatePart();
+                catalogPart = new CatalogPart(part);
+
+                IDisposable disposablePart = part as IDisposable;
+                if (disposablePart != null)
+                {
+                    using (this._lock.LockStateForWrite())
+                    {
+                        this._partsToDispose.Add(disposablePart);
+                    }
+                }
+            }
+
+            return catalogPart;
+        }
+
+        private CatalogPart GetSharedPart(ComposablePartDefinition partDefinition)
+        {
+            CatalogPart catalogPart = null;
+
+            // look up the part
+            using (this._lock.LockStateForRead())
+            {
+                if (this._activatedParts.TryGetValue(partDefinition, out catalogPart))
+                {
+                    return catalogPart;
+                }
+            }
+
+            // create a part outside of the lock
+            ComposablePart newPart = partDefinition.CreatePart();
+            IDisposable disposableNewPart = newPart as IDisposable;
+
+            using (this._lock.LockStateForWrite())
+            {
+                // check if the part is still not there
+                if (!this._activatedParts.TryGetValue(partDefinition, out catalogPart))
+                {
+                    catalogPart = new CatalogPart(newPart);
+                    this._activatedParts.Add(partDefinition, catalogPart);
+                    if (disposableNewPart != null)
+                    {
+                        this._partsToDispose.Add(disposableNewPart);
+                    }
+
+                    // indiacate the the part has been added
+                    newPart = null;
+                    disposableNewPart = null;
+                }
+            }
+
+            // if disposableNewPart != null, this means we have created a new instance of something disposable and not used it
+            // Dispose of it now
+            if (disposableNewPart != null)
+            {
+                disposableNewPart.Dispose();
+            }
+
+            return catalogPart;
+        }
+
+        private object GetExportedValue(CatalogPart part, ExportDefinition export, bool isSharedPart)
+        {
+            this.ThrowIfDisposed();
+            this.EnsureRunning();
+
+            Assumes.NotNull(part, export);
+
+            // We don't protect against thread racing here, as "importsSatisfied" is merely an optimization
+            // if two threads satisfy imports twice, the results is the same, just the perf hit is heavier.
+
+            bool importsSatisfied = part.ImportsSatisfied;
+            ImportEngine importEngine = importsSatisfied ? null : this._importEngine;
+
+            object exportedValue = CompositionServices.GetExportedValueFromComposedPart(
+                importEngine, part.Part, export);
+
+            if (!importsSatisfied)
+            {
+                // and set "ImportsSatisfied" to true
+                part.ImportsSatisfied = true;
+            }
+
+            // Only hold conditional references for recomposable non-shared parts because we are 
+            // already holding strong references to the shared parts.
+            if (exportedValue != null && !isSharedPart && part.Part.IsRecomposable())
+            {
+                this.PreventPartCollection(exportedValue, part.Part);
+            }
+
+            return exportedValue;
+        }
+
+        private void ReleasePart(object exportedValue, CatalogPart catalogPart, AtomicComposition atomicComposition)
+        {
+            this.ThrowIfDisposed();
+            this.EnsureRunning();
+
+            Assumes.NotNull(catalogPart);
+
+            this._importEngine.ReleaseImports(catalogPart.Part, atomicComposition);
+
+            if (exportedValue != null)
+            {
+                atomicComposition.AddCompleteActionAllowNull(() =>
+                {
+                    this.AllowPartCollection(exportedValue);
+                });
+            }
+
+            IDisposable diposablePart = catalogPart.Part as IDisposable;
+            if (diposablePart != null)
+            {
+                atomicComposition.AddCompleteActionAllowNull(() =>
+                {
+                    bool removed = false;
+                    using (this._lock.LockStateForWrite())
+                    {
+                        removed = this._partsToDispose.Remove(diposablePart);
+                    }
+                    if (removed)
+                    {
+                        diposablePart.Dispose();
+                    }
+                });
+            }
+        }
+
+        private void PreventPartCollection(object exportedValue, ComposablePart part)
+        {
+            Assumes.NotNull(exportedValue, part);
+
+            using (this._lock.LockStateForWrite())
+            {
+                List<ComposablePart> partList;
+
+                ConditionalWeakTable<object, List<ComposablePart>> gcRoots = this._gcRoots;
+                if (gcRoots == null)
+                {
+                    gcRoots = new ConditionalWeakTable<object, List<ComposablePart>>();
+                }
+
+                if (!gcRoots.TryGetValue(exportedValue, out partList))
+                {
+                    partList = new List<ComposablePart>();
+                    gcRoots.Add(exportedValue, partList);
+                }
+
+                partList.Add(part);
+
+                if (this._gcRoots == null)
+                {
+                    Thread.MemoryBarrier();
+                    this._gcRoots = gcRoots;
+                }
+            }
+        }
+
+        private void AllowPartCollection(object gcRoot)
+        {
+            if (this._gcRoots != null)
+            {
+                using (this._lock.LockStateForWrite())
+                {
+                    this._gcRoots.Remove(gcRoot);
+                }
+            }
+        }
+
+        private bool IsRejected(ComposablePartDefinition definition, AtomicComposition atomicComposition)
+        {
+            // Check to see if we're currently working on the definition in question.
+            // Recursive queries always answer optimistically, as if the definition hasn't
+            // been rejected - because if it is we can discard all decisions that were based
+            // on the faulty assumption in the first place.
+            var forceRejectionTest = false;
+            if (atomicComposition != null)
+            {
+                var atomicCompositionQuery = GetAtomicCompositionQuery(atomicComposition);
+                AtomicCompositionQueryState state = atomicCompositionQuery(definition);
+                switch (state)
+                {
+                    case AtomicCompositionQueryState.TreatAsRejected:
+                        return true;
+                    case AtomicCompositionQueryState.TreatAsValidated:
+                        return false;
+                    case AtomicCompositionQueryState.NeedsTesting:
+                        forceRejectionTest = true;
+                        break;
+                    default:
+                        Assumes.IsTrue(state == AtomicCompositionQueryState.Unknown);
+                        // Need to do the work to determine the state
+                        break;
+                }
+            }
+
+            if (!forceRejectionTest)
+            {
+                // Next, anything that has been activated is not rejected
+                using (this._lock.LockStateForRead())
+                {
+                    if (this._activatedParts.ContainsKey(definition))
+                    {
+                        return false;
+                    }
+
+                    // Last stop before doing the hard work: check a specific registry of rejected parts
+                    if (this._rejectedParts.Contains(definition))
+                    {
+                        return true;
+                    }
+                }
+            }
+
+            // Determine whether or not the definition's imports can be satisfied
+            return DetermineRejection(definition, atomicComposition);
+        }
+
+        private bool DetermineRejection(ComposablePartDefinition definition, AtomicComposition parentAtomicComposition)
+        {
+            ChangeRejectedException exception = null;
+
+            using (var localAtomicComposition = new AtomicComposition(parentAtomicComposition))
+            {
+                // The part definition we're currently working on is treated optimistically
+                // as if we know it hasn't been rejected.  This handles recursion, and if we
+                // later decide that it has been rejected we'll discard all nested progress so
+                // all side-effects of the mistake are erased.
+                //
+                // Note that this means that recursive failures that would be detected by the
+                // import engine are not discovered by rejection currently.  Loops among
+                // prerequisites, runaway import chains involving factories, and prerequisites
+                // that cannot be fully satisfied still result in runtime errors.  Doing
+                // otherwise would be possible but potentially expensive - and could be a v2
+                // improvement if deemed worthwhile.
+                UpdateAtomicCompositionQuery(localAtomicComposition,
+                    def => definition.Equals(def), AtomicCompositionQueryState.TreatAsValidated);
+
+                var newPart = definition.CreatePart();
+                try
+                {
+                    this._importEngine.PreviewImports(newPart, localAtomicComposition);
+
+                    // Reuse the partially-fleshed out part the next time we need a shared
+                    // instance to keep the expense of pre-validation to a minimum.  Note that
+                    // _activatedParts holds references to both shared and non-shared parts.
+                    // The non-shared parts will only be used for rejection purposes only but
+                    // the shared parts will be handed out when requested via GetExports as 
+                    // well as be used for rejection purposes.
+                    localAtomicComposition.AddCompleteActionAllowNull(() =>
+                    {
+                        using (this._lock.LockStateForWrite())
+                        {
+                            if (!this._activatedParts.ContainsKey(definition))
+                            {
+                                this._activatedParts.Add(definition, new CatalogPart(newPart));
+                                IDisposable newDisposablePart = newPart as IDisposable;
+                                if (newDisposablePart != null)
+                                {
+                                    this._partsToDispose.Add(newDisposablePart);
+                                }
+                            }
+                        }
+                    });
+
+                    // Success! Complete any recursive work that was conditioned on this part's validation
+                    localAtomicComposition.Complete();
+
+                    return false;
+                }
+                catch (ChangeRejectedException ex)
+                {
+                    exception = ex;
+                }
+            }
+
+            // If we've reached this point then this part has been rejected so we need to 
+            // record the rejection in our parent composition or execute it immediately if 
+            // one doesn't exist.
+            parentAtomicComposition.AddCompleteActionAllowNull(() =>
+            {
+                using (this._lock.LockStateForWrite())
+                {
+                    this._rejectedParts.Add(definition);
+                }
+
+                CompositionTrace.PartDefinitionRejected(definition, exception);
+
+            });
+            if (parentAtomicComposition != null)
+            {
+                UpdateAtomicCompositionQuery(parentAtomicComposition,
+                    def => definition.Equals(def), AtomicCompositionQueryState.TreatAsRejected);
+            }
+
+            return true;
+        }
+
+        private void UpdateRejections(IEnumerable<ExportDefinition> changedExports, AtomicComposition atomicComposition)
+        {
+            using (var localAtomicComposition = new AtomicComposition(atomicComposition))
+            {
+                // Reconsider every part definition that has been previously
+                // rejected to see if any of them can be added back.
+                var affectedRejections = new HashSet<ComposablePartDefinition>();
+                var atomicCompositionQuery = GetAtomicCompositionQuery(localAtomicComposition);
+
+                ComposablePartDefinition[] rejectedParts;
+                using (this._lock.LockStateForRead())
+                {
+                    rejectedParts = this._rejectedParts.ToArray();
+                }
+                foreach (var definition in rejectedParts)
+                {
+                    if (atomicCompositionQuery(definition) == AtomicCompositionQueryState.TreatAsValidated)
+                    {
+                        continue;
+                    }
+
+                    foreach (var import in definition.ImportDefinitions.Where(ImportEngine.IsRequiredImportForPreview))
+                    {
+                        if (changedExports.Any(export => import.IsConstraintSatisfiedBy(export)))
+                        {
+                            affectedRejections.Add(definition);
+                            break;
+                        }
+                    }
+                }
+                UpdateAtomicCompositionQuery(localAtomicComposition,
+                    def => affectedRejections.Contains(def), AtomicCompositionQueryState.NeedsTesting);
+
+                // Determine if any of the resurrectable parts is now available so that we can
+                // notify listeners of the exact changes to exports
+                var resurrectedExports = new List<ExportDefinition>();
+
+                foreach (var partDefinition in affectedRejections)
+                {
+                    if (!IsRejected(partDefinition, localAtomicComposition))
+                    {
+                        // Notify listeners of the newly available exports and
+                        // prepare to remove the rejected part from the list of rejections
+                        resurrectedExports.AddRange(partDefinition.ExportDefinitions);
+
+                        // Capture the local so that the closure below refers to the current definition
+                        // in the loop and not the value of 'partDefinition' when the closure executes
+                        var capturedPartDefinition = partDefinition;
+                        localAtomicComposition.AddCompleteAction(() =>
+                        {
+                            using (this._lock.LockStateForWrite())
+                            {
+                                this._rejectedParts.Remove(capturedPartDefinition);                                
+                            }
+
+                            CompositionTrace.PartDefinitionResurrected(capturedPartDefinition);
+                        });
+                    }
+                }
+
+                // Notify anyone sourcing exports that the resurrected exports have appeared
+                if (resurrectedExports.Any())
+                {
+                    this.OnExportsChanging(
+                        new ExportsChangeEventArgs(resurrectedExports, new ExportDefinition[0], localAtomicComposition));
+
+                    localAtomicComposition.AddCompleteAction(() => this.OnExportsChanged(
+                        new ExportsChangeEventArgs(resurrectedExports, new ExportDefinition[0], null)));
+                }
+
+                localAtomicComposition.Complete();
+            }
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+
+        /// <summary>
+        ///  EnsureCanRun must be called from within a lock.
+        /// </summary>
+        [DebuggerStepThrough]
+        private void EnsureCanRun()
+        {
+            if ((this._sourceProvider == null) || (this._importEngine == null))
+            {
+                throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, Strings.ObjectMustBeInitialized, "SourceProvider")); // NOLOC
+            }
+        }
+
+        [DebuggerStepThrough]
+        private void EnsureRunning()
+        {
+            if (!this._isRunning)
+            {
+                using (this._lock.LockStateForWrite())
+                {
+                    if (!this._isRunning)
+                    {
+                        this.EnsureCanRun();
+                        this._isRunning = true;
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        ///  EnsureCanSet<T> must be called from within a lock.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="currentValue"></param>
+        [DebuggerStepThrough]
+        private void EnsureCanSet<T>(T currentValue)
+            where T : class
+        {
+            if ((this._isRunning) || (currentValue != null))
+            {
+                throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, Strings.ObjectAlreadyInitialized));
+            }
+        }
+
+        private Func<ComposablePartDefinition, AtomicCompositionQueryState> GetAtomicCompositionQuery(AtomicComposition atomicComposition)
+        {
+            Func<ComposablePartDefinition, AtomicCompositionQueryState> atomicCompositionQuery;
+            atomicComposition.TryGetValue(this, out atomicCompositionQuery);
+
+            if (atomicCompositionQuery == null)
+            {
+                return (definition) => AtomicCompositionQueryState.Unknown;
+            }
+
+            return atomicCompositionQuery;
+        }
+
+        private void UpdateAtomicCompositionQuery(
+            AtomicComposition atomicComposition,
+            Func<ComposablePartDefinition, bool> query,
+            AtomicCompositionQueryState state)
+        {
+            var parentQuery = GetAtomicCompositionQuery(atomicComposition);
+            Func<ComposablePartDefinition, AtomicCompositionQueryState> newQuery = definition =>
+            {
+                if (query(definition))
+                {
+                    return state;
+                }
+                return parentQuery(definition);
+            };
+
+            atomicComposition.SetValue(this, newQuery);
+        }
+
+        private enum AtomicCompositionQueryState
+        {
+            Unknown,
+            TreatAsRejected,
+            TreatAsValidated,
+            NeedsTesting
+        };
+
+        private class CatalogPart
+        {
+            private volatile bool _importsSatisfied = false;
+            public CatalogPart(ComposablePart part)
+            {
+                this.Part = part;
+            }
+            public ComposablePart Part { get; private set; }
+
+            public bool ImportsSatisfied
+            {
+                get
+                {
+                    return this._importsSatisfied;
+                }
+                set
+                {
+                    this._importsSatisfied = value;
+                }
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExtensions.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExtensions.cs
new file mode 100644
index 00000000000..15308a2380b
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CatalogExtensions.cs
@@ -0,0 +1,26 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Linq;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public static class CatalogExtensions
+    {
+        /// <summary>
+        /// Creates a <see cref="CompositionService"/>.
+        /// </summary>
+        /// <param name="catalog">The catalog.</param>
+        /// <returns>The newly created <see cref="CompositionService"/> 
+        public static CompositionService CreateCompositionService(this ComposablePartCatalog composablePartCatalog)
+        {
+            Requires.NotNull(composablePartCatalog, "composablePartCatalog");
+
+            return new CompositionService(composablePartCatalog);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ComposablePartCatalogChangeEventArgs.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ComposablePartCatalogChangeEventArgs.cs
new file mode 100644
index 00000000000..b7ff41a7fc3
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ComposablePartCatalogChangeEventArgs.cs
@@ -0,0 +1,101 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.Contracts;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    /// <summary>
+    ///     Provides data for the <see cref="INotifyComposablePartCatalogChanged.Changed"/> and
+    ///     <see cref="INotifyComposablePartCatalogChanged.Changing"/> events.
+    /// </summary>
+    public class ComposablePartCatalogChangeEventArgs : EventArgs
+    {
+        private readonly IEnumerable<ComposablePartDefinition> _addedDefinitions;
+        private readonly IEnumerable<ComposablePartDefinition> _removedDefinitions;
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ComposablePartCatalogChangeEventArgs"/>.
+        /// </summary>
+        /// <param name="addedDefinitions">
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="ComposablePartDefinition"/> objects that 
+        ///     are being added to the <see cref="ComposablePartCatalog"/>.
+        /// </param>
+        /// <param name="removedDefinitions">
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="ComposablePartDefinition"/> objects that 
+        ///     are being removed from the <see cref="ComposablePartCatalog"/>.
+        /// </param>
+        /// <param name="atomicComposition">
+        ///     A <see cref="AtomicComposition"/> representing all tentative changes that will
+        ///     be completed if the change is successful, or discarded if it is not. 
+        ///     <see langword="null"/> if being applied outside a <see cref="AtomicComposition"/> 
+        ///     or during a <see cref="INotifyComposablePartCatalogChanged.Changed"/> event.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="addedDefinitions"/> or <paramref name="removedDefinitions"/> is <see langword="null"/>.
+        /// </exception>
+        public ComposablePartCatalogChangeEventArgs(IEnumerable<ComposablePartDefinition> addedDefinitions,
+            IEnumerable<ComposablePartDefinition> removedDefinitions, AtomicComposition atomicComposition)
+        {
+            Requires.NotNull(addedDefinitions, "addedDefinitions");
+            Requires.NotNull(removedDefinitions, "removedDefinitions");
+
+            this._addedDefinitions = addedDefinitions.AsArray();
+            this._removedDefinitions = removedDefinitions.AsArray();
+            this.AtomicComposition = atomicComposition;
+        }
+
+        /// <summary>
+        ///     Gets the identifiers of the parts that have been added.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="ComposablePartDefinition"/> objects that 
+        ///     have been added to the <see cref="ComposablePartCatalog"/>.
+        /// </value>
+        public IEnumerable<ComposablePartDefinition> AddedDefinitions 
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<IEnumerable<ComposablePartDefinition>>() != null);
+
+                return this._addedDefinitions;
+            }
+        }
+
+        /// <summary>
+        ///     Gets the identifiers of the parts that have been removed.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="ComposablePartDefinition"/> objects that 
+        ///     have been removed from from the <see cref="ComposablePartCatalog"/>.
+        /// </value>
+        public IEnumerable<ComposablePartDefinition> RemovedDefinitions 
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<IEnumerable<ComposablePartDefinition>>() != null);
+                
+                return this._removedDefinitions;
+            }
+        }
+
+        /// <summary>
+        ///     Gets the atomicComposition, if any, that this change applies to.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="AtomicComposition"/> that this set of changes applies too. 
+        ///     It can be <see langword="null"/> if the changes are being applied outside a 
+        ///     <see cref="AtomicComposition"/> or during a 
+        ///     <see cref="INotifyComposablePartCatalogChanged.Changed"/> event.
+        ///     
+        ///     When the value is non-null it should be used to record temporary changed state
+        ///     and actions that will be executed when the atomicComposition is completeed.
+        /// </value>
+        public AtomicComposition AtomicComposition { get; private set; }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ComposablePartCatalogCollection.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ComposablePartCatalogCollection.cs
new file mode 100644
index 00000000000..151162887fc
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ComposablePartCatalogCollection.cs
@@ -0,0 +1,415 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.ObjectModel;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using System.Diagnostics;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using System.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    /// <summary>
+    ///     This class implements a threadsafe ICollection{T} of ComposablePartCatalog.
+    ///     It is exposed as an ICollection(ComposablePartCatalog)
+    ///     It is threadsafe, notifications are not marshalled using a SynchronizationContext.
+    ///     It is Disposable.
+    /// </summary>
+    internal class ComposablePartCatalogCollection : ICollection<ComposablePartCatalog>, INotifyComposablePartCatalogChanged, IDisposable
+    {
+        private readonly Lock _lock = new Lock();
+        private Action<ComposablePartCatalogChangeEventArgs> _onChanged;
+        private Action<ComposablePartCatalogChangeEventArgs> _onChanging;
+        private List<ComposablePartCatalog> _catalogs = new List<ComposablePartCatalog>();
+        private volatile bool _isCopyNeeded = false;
+        private volatile bool _isDisposed = false;
+        private bool _hasChanged = false;
+
+        public ComposablePartCatalogCollection(
+            IEnumerable<ComposablePartCatalog> catalogs,
+            Action<ComposablePartCatalogChangeEventArgs> onChanged,
+            Action<ComposablePartCatalogChangeEventArgs> onChanging)
+        {
+            catalogs = catalogs ?? Enumerable.Empty<ComposablePartCatalog>();
+            this._catalogs = new List<ComposablePartCatalog>(catalogs);
+            this._onChanged = onChanged;
+            this._onChanging = onChanging;
+
+            SubscribeToCatalogNotifications(catalogs);
+        }
+
+        public void Add(ComposablePartCatalog item)
+        {
+            Requires.NotNull(item, "item");
+
+            this.ThrowIfDisposed();
+
+            var addedParts = new Lazy<IEnumerable<ComposablePartDefinition>>(() => item.ToArray(), LazyThreadSafetyMode.PublicationOnly);
+
+            using (var atomicComposition = new AtomicComposition())
+            {
+                this.RaiseChangingEvent(addedParts, null, atomicComposition);
+ 
+                using (new WriteLock(this._lock))
+                {
+                    if (this._isCopyNeeded)
+                    {
+                        this._catalogs = new List<ComposablePartCatalog>(this._catalogs);
+                        this._isCopyNeeded = false;
+                    }
+                    this._hasChanged = true;
+                    this._catalogs.Add(item);
+                }
+                
+                this.SubscribeToCatalogNotifications(item);
+
+                // Complete after the catalog changes are written
+                atomicComposition.Complete();
+            }
+
+            this.RaiseChangedEvent(addedParts, null);
+        }
+
+        /// <summary>
+        /// Notify when the contents of the Catalog has changed.
+        /// </summary>
+        public event EventHandler<ComposablePartCatalogChangeEventArgs> Changed;
+
+        /// <summary>
+        /// Notify when the contents of the Catalog has changing.
+        /// </summary>
+        public event EventHandler<ComposablePartCatalogChangeEventArgs> Changing;
+
+        public void Clear()
+        {
+            this.ThrowIfDisposed();
+
+            // No action is required if we are already empty
+            ComposablePartCatalog[] catalogs = null;
+            using (new ReadLock(this._lock))
+            {
+                if (this._catalogs.Count == 0)
+                {
+                    return;
+                }
+                catalogs = this._catalogs.ToArray();
+            }
+
+            //TODO-MT: This is pretty suspect - we can easily eliminate catalogs that aren't listed as being
+            // removed.  Then again, the idea of trying to mutate the catalog on two threads at the same time is pretty
+            // suspect to begin with.  When would that ever result in a meaningful composition?
+
+            // We are doing this outside of the lock, so it's possible that the catalog will continute propagating events from things
+            // we are about to unsubscribe from. Given the non-specificity of our event, in the worst case scenario we would simply fire 
+            // unnecessary events.
+
+            var removedParts = new Lazy<IEnumerable<ComposablePartDefinition>>(() => catalogs.SelectMany(catalog => catalog).ToArray(), LazyThreadSafetyMode.PublicationOnly);
+
+            // Validate the changes before applying them
+            using (var atomicComposition = new AtomicComposition())
+            {
+                this.RaiseChangingEvent(null, removedParts, atomicComposition);
+                this.UnsubscribeFromCatalogNotifications(catalogs);
+
+                using (new WriteLock(this._lock))
+                {
+                    this._catalogs = new List<ComposablePartCatalog>();
+
+                    this._isCopyNeeded = false;
+                    this._hasChanged = true;
+                }
+
+                // Complete after the catalog changes are written
+                atomicComposition.Complete();
+            }
+
+            this.RaiseChangedEvent(null, removedParts);
+        }
+
+        public bool Contains(ComposablePartCatalog item)
+        {
+            Requires.NotNull(item, "item");
+
+            this.ThrowIfDisposed();
+
+            using (new ReadLock(this._lock))
+            {
+                return this._catalogs.Contains(item);
+            }
+        }
+
+        public void CopyTo(ComposablePartCatalog[] array, int arrayIndex)
+        {
+            this.ThrowIfDisposed();
+
+            using (new ReadLock(this._lock))
+            {
+                this._catalogs.CopyTo(array, arrayIndex);
+            }
+        }
+
+        public int Count
+        {
+            get 
+            {
+                this.ThrowIfDisposed();
+
+                using (new ReadLock(this._lock))
+                {
+                    return this._catalogs.Count;
+                }
+            }
+        }
+
+        public bool IsReadOnly
+        {
+            get
+            {
+                this.ThrowIfDisposed();
+
+                return false;
+            }
+        }
+
+        public bool Remove(ComposablePartCatalog item)
+        {
+            Requires.NotNull(item, "item");
+
+            this.ThrowIfDisposed();
+
+            using (new ReadLock(this._lock))
+            {
+                if (!this._catalogs.Contains(item))
+                {
+                    return false;
+                }
+            }
+
+            bool isSuccessfulRemoval = false;
+
+            var removedParts = new Lazy<IEnumerable<ComposablePartDefinition>>(() => item.ToArray(), LazyThreadSafetyMode.PublicationOnly);
+            using (var atomicComposition = new AtomicComposition())
+            {
+                this.RaiseChangingEvent(null, removedParts, atomicComposition);
+
+                using (new WriteLock(this._lock))
+                {
+                    if (_isCopyNeeded)
+                    {
+                        this._catalogs = new List<ComposablePartCatalog>(this._catalogs);
+                        this._isCopyNeeded = false;
+                    }
+
+                    isSuccessfulRemoval = this._catalogs.Remove(item);
+                    if (isSuccessfulRemoval)
+                    {
+                        this._hasChanged = true;
+                    }
+                }
+
+                this.UnsubscribeFromCatalogNotifications(item);
+
+                // Complete after the catalog changes are written
+                atomicComposition.Complete();
+            }
+
+            this.RaiseChangedEvent(null, removedParts);
+
+            return isSuccessfulRemoval;
+        }
+
+        internal bool HasChanged
+        {
+            get
+            {
+                this.ThrowIfDisposed();
+
+                using (new ReadLock(this._lock))
+                {
+                    return this._hasChanged;
+                }
+            }
+        }
+
+        public IEnumerator<ComposablePartCatalog> GetEnumerator()
+        {
+            this.ThrowIfDisposed();
+
+            using (new WriteLock(this._lock))
+            {
+                IEnumerator<ComposablePartCatalog> enumerator = this._catalogs.GetEnumerator();
+                this._isCopyNeeded = true;
+                return enumerator;
+            }
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return this.GetEnumerator();
+        }
+
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        protected virtual void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                if (!this._isDisposed)
+                {
+                    bool disposeLock = false;
+                    IEnumerable<ComposablePartCatalog> catalogs = null;
+                    try
+                    {
+                        using (new WriteLock(this._lock))
+                        {
+                            if (!this._isDisposed)
+                            {
+                                disposeLock = true;
+
+                                catalogs = this._catalogs;
+                                this._catalogs = null;
+
+                                this._isDisposed = true;
+                            }
+                        }
+                    }
+                    finally
+                    {
+                        if (catalogs != null)
+                        {
+                            this.UnsubscribeFromCatalogNotifications(catalogs);
+                            catalogs.ForEach(catalog => catalog.Dispose());
+                        }
+
+                        if (disposeLock)
+                        {
+                            this._lock.Dispose();
+                        }
+                    }
+                }
+            }
+        }
+
+        private void RaiseChangedEvent(
+            Lazy<IEnumerable<ComposablePartDefinition>> addedDefinitions,
+            Lazy<IEnumerable<ComposablePartDefinition>> removedDefinitions)
+        {
+            if (this._onChanged == null || this.Changed == null)
+            {
+                return;
+            }
+
+            var added = (addedDefinitions == null ? Enumerable.Empty<ComposablePartDefinition>() : addedDefinitions.Value);
+            var removed = (removedDefinitions == null ? Enumerable.Empty<ComposablePartDefinition>() : removedDefinitions.Value);
+
+            this._onChanged.Invoke(new ComposablePartCatalogChangeEventArgs(added, removed, null));
+        }
+
+        public void OnChanged(object sender, ComposablePartCatalogChangeEventArgs e)
+        {
+            var changedEvent = this.Changed;
+            if (changedEvent != null)
+            {
+                changedEvent(sender, e);
+            }
+        }
+
+        private void RaiseChangingEvent(
+           Lazy<IEnumerable<ComposablePartDefinition>> addedDefinitions,
+           Lazy<IEnumerable<ComposablePartDefinition>> removedDefinitions,
+           AtomicComposition atomicComposition)
+        {
+            if (this._onChanging == null || this.Changing == null)
+            {
+                return;
+            }
+            var added = (addedDefinitions == null ? Enumerable.Empty<ComposablePartDefinition>() : addedDefinitions.Value);
+            var removed = (removedDefinitions == null ? Enumerable.Empty<ComposablePartDefinition>() : removedDefinitions.Value);
+
+            this._onChanging.Invoke(new ComposablePartCatalogChangeEventArgs(added, removed, atomicComposition));
+        }
+
+        public void OnChanging(object sender, ComposablePartCatalogChangeEventArgs e)
+        {
+            var changingEvent = this.Changing;
+            if (changingEvent != null)
+            {
+                changingEvent(sender, e);
+            }
+        }
+
+        private void OnContainedCatalogChanged(object sender, ComposablePartCatalogChangeEventArgs e)
+        {
+            if (this._onChanged == null || this.Changed == null)
+            {
+                return;
+            }
+
+            this._onChanged.Invoke(e);
+        }
+
+        private void OnContainedCatalogChanging(object sender, ComposablePartCatalogChangeEventArgs e)
+        {
+            if (this._onChanging == null || this.Changing == null)
+            {
+                return;
+            }
+
+            this._onChanging.Invoke(e);
+        }
+
+        private void SubscribeToCatalogNotifications(ComposablePartCatalog catalog)
+        {
+            INotifyComposablePartCatalogChanged notifyCatalog = catalog as INotifyComposablePartCatalogChanged;
+            if (notifyCatalog != null)
+            {
+                notifyCatalog.Changed += this.OnContainedCatalogChanged;
+                notifyCatalog.Changing += this.OnContainedCatalogChanging;
+            }
+        }
+
+        private void SubscribeToCatalogNotifications(IEnumerable<ComposablePartCatalog> catalogs)
+        {
+            foreach (var catalog in catalogs)
+            {
+                SubscribeToCatalogNotifications(catalog);
+            }
+        }
+
+        private void UnsubscribeFromCatalogNotifications(ComposablePartCatalog catalog)
+        {
+            INotifyComposablePartCatalogChanged notifyCatalog = catalog as INotifyComposablePartCatalogChanged;
+            if (notifyCatalog != null)
+            {
+                notifyCatalog.Changed -= this.OnContainedCatalogChanged;
+                notifyCatalog.Changing -= this.OnContainedCatalogChanging;
+            }
+        }
+
+        private void UnsubscribeFromCatalogNotifications(IEnumerable<ComposablePartCatalog> catalogs)
+        {
+            foreach (var catalog in catalogs)
+            {
+                UnsubscribeFromCatalogNotifications(catalog);
+            }
+        }
+
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ComposablePartExportProvider.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ComposablePartExportProvider.cs
new file mode 100644
index 00000000000..dc0bc251be4
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ComposablePartExportProvider.cs
@@ -0,0 +1,449 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Globalization;
+using System.Linq;
+using System.Threading;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public class ComposablePartExportProvider : ExportProvider, IDisposable
+    {
+        private List<ComposablePart> _parts = new List<ComposablePart>();
+        private volatile bool _isDisposed = false;
+        private volatile bool _isRunning = false;
+        private CompositionLock _lock = null;
+        private ExportProvider _sourceProvider;
+        private ImportEngine _importEngine;
+        private volatile bool _currentlyComposing;
+        private CompositionOptions _compositionOptions;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ComposablePartExportProvider"/> class.
+        /// </summary>
+        public ComposablePartExportProvider() : 
+            this(false)
+        {
+        }
+
+        public ComposablePartExportProvider(bool isThreadSafe)
+            :this(isThreadSafe ? CompositionOptions.IsThreadSafe : CompositionOptions.Default)
+        {
+        }
+
+        public ComposablePartExportProvider(CompositionOptions compositionOptions)
+        {
+            if (compositionOptions > (CompositionOptions.DisableSilentRejection | CompositionOptions.IsThreadSafe | CompositionOptions.ExportCompositionService))
+            {
+                throw new ArgumentOutOfRangeException("compositionOptions");
+            }
+
+            this._compositionOptions = compositionOptions;
+            this._lock = new CompositionLock(compositionOptions.HasFlag(CompositionOptions.IsThreadSafe));
+        }
+
+        /// <summary>
+        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
+        /// </summary>
+        public void Dispose()
+        {
+            this.Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        /// <summary>
+        /// Releases unmanaged and - optionally - managed resources
+        /// </summary>
+        /// <param name="disposing"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
+        protected virtual void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                if (!this._isDisposed)
+                {
+                    bool disposeLock = false;
+                    ImportEngine importEngine = null;
+                    try
+                    {
+                        using (this._lock.LockStateForWrite())
+                        {
+                            if (!this._isDisposed)
+                            {
+                                importEngine = this._importEngine;
+                                this._importEngine = null;
+
+                                this._sourceProvider = null;
+                                this._isDisposed = true;
+                                disposeLock = true;
+                            }
+                        }
+                    }
+                    finally
+                    {
+                        if (importEngine != null)
+                        {
+                            importEngine.Dispose();
+                        }
+
+                        if (disposeLock)
+                        {
+                            this._lock.Dispose();
+                        }
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        ///     Gets the export provider which provides the provider access to
+        ///     exports.
+        /// </summary>
+        /// <value>
+        ///     The <see cref="ExportProvider"/> which provides the 
+        ///     <see cref="ComposablePartExportProvider"/> access to <see cref="Export"/> objects. 
+        ///     The default is <see langword="null"/>.
+        /// </value>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="value"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="InvalidOperationException">
+        ///     This property has already been set.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     The methods on the <see cref="ComposablePartExportProvider"/> 
+        ///     have already been accessed.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ComposablePartExportProvider"/> has been disposed of.
+        /// </exception>
+        /// <remarks>
+        ///     This property must be set before accessing any methods on the 
+        ///     <see cref="ComposablePartExportProvider"/>.
+        /// </remarks>
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope", Justification = "EnsureCanSet ensures that the property is set only once, Dispose is not required")]
+        public ExportProvider SourceProvider
+        {
+            get
+            {
+                this.ThrowIfDisposed();
+
+                return this._sourceProvider;
+            }
+            set
+            {
+                this.ThrowIfDisposed();
+
+                Requires.NotNull(value, "value");
+                using (this._lock.LockStateForWrite())
+                {
+                    this.EnsureCanSet(this._sourceProvider);
+                    this._sourceProvider = value;
+                }
+            }
+        }
+
+        private ImportEngine ImportEngine
+        {
+            get
+            {
+                if (this._importEngine == null)
+                {
+                    Assumes.NotNull(this._sourceProvider);
+                    ImportEngine importEngine = new ImportEngine(this._sourceProvider, this._compositionOptions);
+                    using (this._lock.LockStateForWrite())
+                    {
+                        if (this._importEngine == null)
+                        {
+                            Thread.MemoryBarrier();
+                            this._importEngine = importEngine;
+                            importEngine = null;
+                        }
+                    }
+
+                    // if we have created an engine and didn't set it because of a race condition, we need to dispose of it
+                    if (importEngine != null)
+                    {
+                        importEngine.Dispose();
+                    }
+                }
+
+                return this._importEngine;
+            }
+        }
+
+
+        /// <summary>
+        /// Returns all exports that match the conditions of the specified import.
+        /// </summary>
+        /// <param name="definition">The <see cref="ImportDefinition"/> that defines the conditions of the
+        /// <see cref="Export"/> to get.</param>
+        /// <returns></returns>
+        /// <result>
+        /// An <see cref="IEnumerable{T}"/> of <see cref="Export"/> objects that match
+        /// the conditions defined by <see cref="ImportDefinition"/>, if found; otherwise, an
+        /// empty <see cref="IEnumerable{T}"/>.
+        /// </result>
+        /// <remarks>
+        /// 	<note type="inheritinfo">
+        /// The implementers should not treat the cardinality-related mismatches as errors, and are not
+        /// expected to throw exceptions in those cases.
+        /// For instance, if the import requests exactly one export and the provider has no matching exports or more than one,
+        /// it should return an empty <see cref="IEnumerable{T}"/> of <see cref="Export"/>.
+        /// </note>
+        /// </remarks>
+        protected override IEnumerable<Export> GetExportsCore(ImportDefinition definition, AtomicComposition atomicComposition)
+        {
+            this.ThrowIfDisposed();
+            this.EnsureRunning();
+
+            // Determine whether there is a composition atomicComposition-specific list of parts to use,
+            // failing that use the usual list.  We never change the list of parts in place,
+            // but rather copy, change and write a new list atomically.  Therefore all we need
+            // to do here is to read the _parts member.
+            List<ComposablePart> parts = null;
+            using (this._lock.LockStateForRead())
+            {
+                parts = atomicComposition.GetValueAllowNull(this, this._parts);
+            }
+
+            if (parts.Count == 0)
+            {
+                return null;
+            }
+
+            List<Export> exports = new List<Export>();
+            foreach (var part in parts)
+            {
+                foreach (var exportDefinition in part.ExportDefinitions)
+                {
+                    if (definition.IsConstraintSatisfiedBy(exportDefinition))
+                    {
+                        exports.Add(this.CreateExport(part, exportDefinition));
+                    }
+                }
+            }
+            return exports;
+        }    
+
+        public void Compose(CompositionBatch batch)
+        {
+            this.ThrowIfDisposed();
+            this.EnsureRunning();
+
+            Requires.NotNull(batch, "batch");
+
+            // Quick exit test can be done prior to cloning since it's just an optimization, not a
+            // change in behavior
+            if ((batch.PartsToAdd.Count == 0) && (batch.PartsToRemove.Count == 0))
+            {
+                return;
+            }
+
+            CompositionResult result = CompositionResult.SucceededResult;
+
+            // Get updated parts list and a cloned batch
+            var newParts = GetUpdatedPartsList(ref batch);
+
+            // Allow only recursive calls from the import engine to see the changes until
+            // they've been verified ...
+            using (var atomicComposition = new AtomicComposition())
+            {
+                // Don't allow reentrant calls to compose during previewing to prevent
+                // corrupted state.
+                if (this._currentlyComposing)
+                {
+                    throw new InvalidOperationException(Strings.ReentrantCompose);
+                }
+
+                this._currentlyComposing = true;
+
+                try
+                {
+                    // In the meantime recursive calls need to be able to see the list as well
+                    atomicComposition.SetValue(this, newParts);
+
+                    // Recompose any existing imports effected by the these changes first so that
+                    // adapters, resurrected parts, etc. can all play their role in satisfying
+                    // imports for added parts
+                    this.Recompose(batch, atomicComposition);
+
+                    // Ensure that required imports can be satisfied
+                    foreach (ComposablePart part in batch.PartsToAdd)
+                    {
+                        // collect the result of previewing all the adds in the batch
+                        try
+                        {
+                            this.ImportEngine.PreviewImports(part, atomicComposition);
+                        }
+                        catch (ChangeRejectedException ex)
+                        {
+                            result = result.MergeResult(new CompositionResult(ex.Errors));
+                        }
+                    }
+
+                    result.ThrowOnErrors(atomicComposition);
+
+                    // Complete the new parts since they passed previewing.`
+                    using (this._lock.LockStateForWrite())
+                    {
+                        this._parts = newParts;
+                    }
+
+                    atomicComposition.Complete();
+                }
+                finally
+                {
+                    this._currentlyComposing = false;
+                }
+            }
+
+            // Satisfy Imports
+            // - Satisfy imports on all newly added component parts
+            foreach (ComposablePart part in batch.PartsToAdd)
+            {
+                result = result.MergeResult(CompositionServices.TryInvoke(() =>
+                    this.ImportEngine.SatisfyImports(part)));
+            }
+
+            // return errors
+            result.ThrowOnErrors();
+        }
+
+        private List<ComposablePart> GetUpdatedPartsList(ref CompositionBatch batch)
+        {
+            Assumes.NotNull(batch);
+
+            // Copy the current list of parts - we are about to modify it
+            // This is an OK thing to do as this is the only method that can modify the List AND Compose can
+            // only be executed on one thread at a time - thus two different threads cannot tramp over each other
+            List<ComposablePart> parts = null;
+            using (this._lock.LockStateForRead())
+            {
+                parts = this._parts.ToList(); // this copies the list
+            }
+
+            foreach (ComposablePart part in batch.PartsToAdd)
+            {
+                parts.Add(part);
+            }
+
+            List<ComposablePart> partsToRemove = null;
+
+            foreach (ComposablePart part in batch.PartsToRemove)
+            {
+                if (parts.Remove(part))
+                {
+                    if (partsToRemove == null)
+                    {
+                        partsToRemove = new List<ComposablePart>();
+                    }
+                    partsToRemove.Add(part);
+                }
+            }
+
+            // Clone the batch, so that the external changes wouldn't happen half-way thorugh compose
+            // NOTE : this does not guarantee the atomicity of cloning, which is not the goal anyway, 
+            // rather the fact that all subsequent calls will deal with an unchanging batch
+            batch = new CompositionBatch(batch.PartsToAdd, partsToRemove);
+
+            return parts;
+        }
+
+        private void Recompose(CompositionBatch batch, AtomicComposition atomicComposition)
+        {
+            Assumes.NotNull(batch);
+
+            // Unregister any removed component parts
+            foreach (ComposablePart part in batch.PartsToRemove)
+            {
+                this.ImportEngine.ReleaseImports(part, atomicComposition);
+            }
+
+            // Recompose any imports effected by the these changes (the changes are
+            // observable through GetExports in the appropriate atomicComposition, thus we can fire
+            // the event
+            IEnumerable<ExportDefinition> addedExports = batch.PartsToAdd.Count != 0 ?
+                batch.PartsToAdd.SelectMany(part => part.ExportDefinitions).ToArray() :
+                new ExportDefinition[0];
+
+            IEnumerable<ExportDefinition> removedExports = batch.PartsToRemove.Count != 0 ?
+                batch.PartsToRemove.SelectMany(part => part.ExportDefinitions).ToArray() :
+                new ExportDefinition[0];
+
+            this.OnExportsChanging(
+                new ExportsChangeEventArgs(addedExports, removedExports, atomicComposition));
+
+            atomicComposition.AddCompleteAction(() => this.OnExportsChanged(
+                new ExportsChangeEventArgs(addedExports, removedExports, null)));
+        }
+
+        private Export CreateExport(ComposablePart part, ExportDefinition export)
+        {
+            return new Export(export, () => GetExportedValue(part, export));
+        }
+
+        private object GetExportedValue(ComposablePart part, ExportDefinition export)
+        {
+            this.ThrowIfDisposed();
+            this.EnsureRunning();
+
+            return CompositionServices.GetExportedValueFromComposedPart(this.ImportEngine, part, export);
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed)
+            {
+                throw new ObjectDisposedException(this.GetType().Name);
+            }
+        }
+
+        [DebuggerStepThrough]
+        private void EnsureCanRun()
+        {
+            if (this._sourceProvider == null)
+            {
+                throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, Strings.ObjectMustBeInitialized, "SourceProvider")); // NOLOC
+            }
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void EnsureRunning()
+        {
+            if (!this._isRunning)
+            {
+                using (this._lock.LockStateForWrite())
+                {
+                    if (!this._isRunning)
+                    {
+                        this.EnsureCanRun();
+                        this._isRunning = true;
+                    }
+                }
+            }
+        }
+
+        [DebuggerStepThrough]
+        private void EnsureCanSet<T>(T currentValue)
+            where T : class
+        {
+            if ((this._isRunning) || (currentValue != null))
+            {
+                throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, Strings.ObjectAlreadyInitialized));
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionBatch.SingleExportComposablePart.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionBatch.SingleExportComposablePart.cs
new file mode 100644
index 00000000000..fd5875e5b40
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionBatch.SingleExportComposablePart.cs
@@ -0,0 +1,62 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Linq;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    partial class CompositionBatch
+    {
+        // Represents a part that exports a single export
+        private class SingleExportComposablePart : ComposablePart
+        {
+            private readonly Export _export;
+
+            public SingleExportComposablePart(Export export)
+            {
+                Assumes.NotNull(export);
+
+                this._export = export;
+            }
+
+            public override IDictionary<string, object> Metadata
+            {
+                get { return MetadataServices.EmptyMetadata; }
+            }
+
+            public override IEnumerable<ExportDefinition> ExportDefinitions
+            {
+                get { return new ExportDefinition[] { _export.Definition }; }
+            }
+
+            public override IEnumerable<ImportDefinition> ImportDefinitions
+            {
+                get { return Enumerable.Empty<ImportDefinition>(); }
+            }
+
+            public override object GetExportedValue(ExportDefinition definition)
+            {
+                Requires.NotNull(definition, "definition");
+
+                if (definition != _export.Definition)
+                {
+                    throw ExceptionBuilder.CreateExportDefinitionNotOnThisComposablePart("definition");
+                }
+
+                return _export.Value;
+            }
+
+            public override void SetImport(ImportDefinition definition, IEnumerable<Export> exports)
+            {
+                Requires.NotNull(definition, "definition");
+                Requires.NotNullOrNullElements(exports, "exports");
+
+                throw ExceptionBuilder.CreateImportDefinitionNotOnThisComposablePart("definition");
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionBatch.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionBatch.cs
new file mode 100644
index 00000000000..24be4db75dd
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionBatch.cs
@@ -0,0 +1,178 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.Contracts;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class CompositionBatch
+    {
+        private object _lock = new object();
+        private bool _copyNeededForAdd;
+        private bool _copyNeededForRemove;
+        private List<ComposablePart> _partsToAdd;
+        private ReadOnlyCollection<ComposablePart> _readOnlyPartsToAdd;
+        private List<ComposablePart> _partsToRemove;
+        private ReadOnlyCollection<ComposablePart> _readOnlyPartsToRemove;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CompositionBatch"/> class.
+        /// </summary>
+        public CompositionBatch() : 
+            this(null, null)
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CompositionBatch"/> class.
+        /// </summary>
+        /// <param name="partsToAdd">The parts to add.</param>
+        /// <param name="partsToRemove">The parts to remove.</param>
+        public CompositionBatch(IEnumerable<ComposablePart> partsToAdd, IEnumerable<ComposablePart> partsToRemove)
+        {
+            this._partsToAdd = new List<ComposablePart>();
+            if (partsToAdd != null)
+            {
+                foreach (var part in partsToAdd)
+                {
+                    if (part == null)
+                    {
+                        throw ExceptionBuilder.CreateContainsNullElement("partsToAdd");
+                    }
+                    this._partsToAdd.Add(part);
+                }
+            }
+            this._readOnlyPartsToAdd = this._partsToAdd.AsReadOnly();
+
+            this._partsToRemove = new List<ComposablePart>();
+            if (partsToRemove != null)
+            {
+                foreach (var part in partsToRemove)
+                {
+                    if (part == null)
+                    {
+                        throw ExceptionBuilder.CreateContainsNullElement("partsToRemove");
+                    }
+                    this._partsToRemove.Add(part);
+                }
+            }
+            this._readOnlyPartsToRemove = this._partsToRemove.AsReadOnly();
+        }
+
+        /// <summary>
+        /// Returns the collection of parts that will be added.
+        /// </summary>
+        /// <value>The parts to be added.</value>
+        public ReadOnlyCollection<ComposablePart> PartsToAdd
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<ReadOnlyCollection<ComposablePart>>() != null);
+
+                lock (this._lock)
+                {
+                    this._copyNeededForAdd = true;
+                    return this._readOnlyPartsToAdd;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Returns the collection of parts that will be removed.
+        /// </summary>
+        /// <value>The parts to be removed.</value>
+        public ReadOnlyCollection<ComposablePart> PartsToRemove
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result <ReadOnlyCollection<ComposablePart>>() != null);
+
+                lock (this._lock)
+                {
+                    this._copyNeededForRemove = true;
+                    return this._readOnlyPartsToRemove;
+                }
+            }
+        }
+
+        /// <summary>
+        ///     Adds the specified part to the <see cref="CompositionBatch"/>.
+        /// </summary>
+        /// <param name="part">
+        /// The part.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="part"/> is <see langword="null"/>.
+        /// </exception>
+        public void AddPart(ComposablePart part)
+        {
+            Requires.NotNull(part, "part");
+            lock (this._lock)
+            {
+                if (this._copyNeededForAdd)
+                {
+                    this._partsToAdd = new List<ComposablePart>(this._partsToAdd);
+                    this._readOnlyPartsToAdd = this._partsToAdd.AsReadOnly();
+                    this._copyNeededForAdd = false;
+                }
+                this._partsToAdd.Add(part);
+            }
+        }
+
+        /// <summary>
+        ///     Removes the specified part from the <see cref="CompositionBatch"/>.
+        /// </summary>
+        /// <param name="part">
+        /// The part.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="part"/> is <see langword="null"/>.
+        /// </exception>
+        public void RemovePart(ComposablePart part)
+        {
+            Requires.NotNull(part, "part");
+            lock (this._lock)
+            {
+                if (this._copyNeededForRemove)
+                {
+                    this._partsToRemove = new List<ComposablePart>(this._partsToRemove);
+                    this._readOnlyPartsToRemove = this._partsToRemove.AsReadOnly();
+                    this._copyNeededForRemove = false;
+                }
+                this._partsToRemove.Add(part);
+            }
+        }
+
+        /// <summary>
+        ///     Adds the specified export to the <see cref="CompositionBatch"/>.
+        /// </summary>
+        /// <param name="export">
+        ///     The <see cref="Export"/> to add to the <see cref="CompositionBatch"/>.
+        /// </param>
+        /// <returns>
+        ///     A <see cref="ComposablePart"/> that can be used remove the <see cref="Export"/>
+        ///     from the <see cref="CompositionBatch"/>.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="export"/> is <see langword="null"/>.
+        /// </exception>
+        /// <remarks>
+        /// </remarks>
+        public ComposablePart AddExport(Export export)
+        {
+            Requires.NotNull(export, "export");
+            Contract.Ensures(Contract.Result<ComposablePart>() != null);
+
+            ComposablePart part = new SingleExportComposablePart(export);
+
+            this.AddPart(part);
+
+            return part;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionConstants.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionConstants.cs
new file mode 100644
index 00000000000..aae9cfce7c3
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionConstants.cs
@@ -0,0 +1,31 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public static class CompositionConstants
+    {
+        private const string CompositionNamespace = "System.ComponentModel.Composition";
+
+        public const string PartCreationPolicyMetadataName = CompositionNamespace + ".CreationPolicy";
+        public const string ImportSourceMetadataName = CompositionNamespace + ".ImportSource";
+        public const string IsGenericPartMetadataName = CompositionNamespace + ".IsGenericPart";
+        public const string GenericContractMetadataName = CompositionNamespace + ".GenericContractName";
+        public const string GenericParametersMetadataName = CompositionNamespace + ".GenericParameters";
+        public const string ExportTypeIdentityMetadataName = "ExportTypeIdentity";
+
+        internal const string GenericImportParametersOrderMetadataName = CompositionNamespace + ".GenericImportParametersOrderMetadataName";
+        internal const string GenericExportParametersOrderMetadataName = CompositionNamespace + ".GenericExportParametersOrderMetadataName";
+        internal const string GenericPartArityMetadataName = CompositionNamespace + ".GenericPartArity";
+        internal const string GenericParameterConstraintsMetadataName = CompositionNamespace + ".GenericParameterConstraints";
+        internal const string GenericParameterAttributesMetadataName = CompositionNamespace + ".GenericParameterAttributes";
+
+        internal const string ProductDefinitionMetadataName = "ProductDefinition";
+
+        internal const string PartCreatorContractName = CompositionNamespace + ".Contracts.ExportFactory";
+        internal static readonly string PartCreatorTypeIdentity = AttributedModelServices.GetTypeIdentity(typeof(ComposablePartDefinition));
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionContainer.CompositionServiceShim.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionContainer.CompositionServiceShim.cs
new file mode 100644
index 00000000000..3d992138d92
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionContainer.CompositionServiceShim.cs
@@ -0,0 +1,31 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Linq;
+using System.Text;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class CompositionContainer
+    {
+        private class CompositionServiceShim : ICompositionService
+        {
+            CompositionContainer _innerContainer = null;
+
+            public CompositionServiceShim(CompositionContainer innerContainer)
+            {
+                Assumes.NotNull(innerContainer);
+                this._innerContainer = innerContainer;
+            }
+
+            void ICompositionService.SatisfyImportsOnce(ComposablePart part)
+            {
+                this._innerContainer.SatisfyImportsOnce(part);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionContainer.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionContainer.cs
new file mode 100644
index 00000000000..9ac01dcb215
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionContainer.cs
@@ -0,0 +1,589 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Threading;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class CompositionContainer : ExportProvider, ICompositionService, IDisposable
+    {
+        private CompositionOptions _compositionOptions;
+        private ImportEngine _importEngine;
+        private ComposablePartExportProvider _partExportProvider;
+        private ExportProvider _rootProvider;
+        private CatalogExportProvider _catalogExportProvider;
+
+        private AggregateExportProvider _localExportProvider;
+        private AggregateExportProvider _ancestorExportProvider;
+        
+        private readonly ReadOnlyCollection<ExportProvider> _providers;
+        private volatile bool _isDisposed = false;
+        private object _lock = new object();
+        private static ReadOnlyCollection<ExportProvider> EmptyProviders = new ReadOnlyCollection<ExportProvider>(new ExportProvider[]{});
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionContainer"/> class.
+        /// </summary>
+        public CompositionContainer()
+            : this((ComposablePartCatalog)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionContainer"/> class 
+        ///     with the specified export providers.
+        /// </summary>
+        /// <param name="providers">
+        ///     A <see cref="Array"/> of <see cref="ExportProvider"/> objects which provide 
+        ///     the <see cref="CompositionContainer"/> access to <see cref="Export"/> objects,
+        ///     or <see langword="null"/> to set <see cref="Providers"/> to an empty
+        ///     <see cref="ReadOnlyCollection{T}"/>.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="providers"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        public CompositionContainer(params ExportProvider[] providers) : 
+            this((ComposablePartCatalog)null, providers)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionContainer"/> class 
+        ///     with the specified export providers.
+        /// </summary>
+        /// <param name="compositionOPtionss">
+        ///     <see cref="CompositionOptions"/> enumeration with flags controlling the composition.
+        /// </param>
+        /// <param name="providers">
+        ///     A <see cref="Array"/> of <see cref="ExportProvider"/> objects which provide 
+        ///     the <see cref="CompositionContainer"/> access to <see cref="Export"/> objects,
+        ///     or <see langword="null"/> to set <see cref="Providers"/> to an empty
+        ///     <see cref="ReadOnlyCollection{T}"/>.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="providers"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        public CompositionContainer(CompositionOptions compositionOptions, params ExportProvider[] providers) : 
+            this((ComposablePartCatalog)null, compositionOptions, providers)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionContainer"/> class 
+        ///     with the specified catalog and export providers.
+        /// </summary>
+        /// <param name="providers">
+        ///     A <see cref="Array"/> of <see cref="ExportProvider"/> objects which provide 
+        ///     the <see cref="CompositionContainer"/> access to <see cref="Export"/> objects,
+        ///     or <see langword="null"/> to set <see cref="Providers"/> to an empty 
+        ///     <see cref="ReadOnlyCollection{T}"/>.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="providers"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        public CompositionContainer(ComposablePartCatalog catalog, params ExportProvider[] providers): 
+            this(catalog, false, providers)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionContainer"/> class 
+        ///     with the specified catalog and export providers.
+        /// </summary>
+        /// <param name="isThreadSafe">
+        ///     <see cref="bool"/> indicates whether container instances are threadsafe.
+        /// </param>
+        /// <param name="providers">
+        ///     A <see cref="Array"/> of <see cref="ExportProvider"/> objects which provide 
+        ///     the <see cref="CompositionContainer"/> access to <see cref="Export"/> objects,
+        ///     or <see langword="null"/> to set <see cref="Providers"/> to an empty 
+        ///     <see cref="ReadOnlyCollection{T}"/>.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="providers"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        public CompositionContainer(ComposablePartCatalog catalog, bool isThreadSafe, params ExportProvider[] providers)
+            : this(catalog, isThreadSafe ? CompositionOptions.IsThreadSafe : CompositionOptions.Default, providers)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="CompositionContainer"/> class 
+        ///     with the specified catalog and export providers.
+        /// </summary>
+        /// <param name="compositionSettings">
+        ///     <see cref="CompositionOptions"/> enumeration with flags controlling the composition.
+        /// </param>
+        /// <param name="providers">
+        ///     A <see cref="Array"/> of <see cref="ExportProvider"/> objects which provide 
+        ///     the <see cref="CompositionContainer"/> access to <see cref="Export"/> objects,
+        ///     or <see langword="null"/> to set <see cref="Providers"/> to an empty 
+        ///     <see cref="ReadOnlyCollection{T}"/>.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="providers"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        public CompositionContainer(ComposablePartCatalog catalog, CompositionOptions compositionOptions, params ExportProvider[] providers)
+        {
+            if (compositionOptions > (CompositionOptions.DisableSilentRejection | CompositionOptions.IsThreadSafe | CompositionOptions.ExportCompositionService))
+            {
+                throw new ArgumentOutOfRangeException("compositionOptions");
+            }
+            this._compositionOptions = compositionOptions;
+
+            this._partExportProvider = new ComposablePartExportProvider(compositionOptions);
+            this._partExportProvider.SourceProvider = this;
+
+            bool multiProvider = (catalog != null) || providers.Length > 0;
+
+            if (multiProvider)
+            {
+                if (catalog != null)
+                {
+                    this._catalogExportProvider = new CatalogExportProvider(catalog, compositionOptions);
+                    this._catalogExportProvider.SourceProvider = this;
+                    this._localExportProvider = new AggregateExportProvider(this._partExportProvider, this._catalogExportProvider);
+                }
+                else
+                {
+                    this._localExportProvider = new AggregateExportProvider(this._partExportProvider);
+                }
+                if(providers != null && providers.Length > 0)
+                {
+                    this._ancestorExportProvider = new AggregateExportProvider(providers);
+                    this._rootProvider = new AggregateExportProvider(this._localExportProvider, this._ancestorExportProvider);
+                }
+                else
+                {
+                    this._rootProvider = this._localExportProvider;
+                }
+            }
+            else
+            {
+                this._rootProvider = this._partExportProvider;
+            }
+
+            //Insert Composition Service
+            if(compositionOptions.HasFlag(CompositionOptions.ExportCompositionService))
+            {
+                this.ComposeExportedValue<ICompositionService>(new CompositionServiceShim(this));
+            }           
+
+            this._rootProvider.ExportsChanged += this.OnExportsChangedInternal;
+            this._rootProvider.ExportsChanging += this.OnExportsChangingInternal;
+
+            this._providers = (providers != null) ? new ReadOnlyCollection<ExportProvider>((ExportProvider[])providers.Clone()) : EmptyProviders;
+        }
+
+        internal CompositionOptions CompositionOptions
+        {
+            get 
+            {
+                this.ThrowIfDisposed();
+                return _compositionOptions; 
+            }
+        }                                                   
+
+        /// <summary>
+        ///     Gets the catalog which provides the container access to exports produced
+        ///     from composable parts.
+        /// </summary>
+        /// <value>
+        ///     The <see cref="ComposablePartCatalog"/> which provides the 
+        ///     <see cref="CompositionContainer"/> access to exports produced from
+        ///     <see cref="ComposablePart"/> objects. The default is <see langword="null"/>.
+        /// </value>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        public ComposablePartCatalog Catalog
+        {
+            get 
+            {
+                this.ThrowIfDisposed();
+
+                return (this._catalogExportProvider != null) ? this._catalogExportProvider.Catalog : null;
+            }
+        }
+
+        internal CatalogExportProvider CatalogExportProvider
+        {
+            get 
+            {
+                this.ThrowIfDisposed();
+
+                return this._catalogExportProvider;
+            }
+        }
+
+        /// <summary>
+        ///     Gets the export providers which provide the container access to additional exports.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="ReadOnlyCollection{T}"/> of <see cref="ExportProvider"/> objects
+        ///     which provide the <see cref="CompositionContainer"/> access to additional
+        ///     <see cref="Export"/> objects. The default is an empty 
+        ///     <see cref="ReadOnlyCollection{T}"/>.
+        /// </value>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        public ReadOnlyCollection<ExportProvider> Providers
+        {
+            get
+            {
+                this.ThrowIfDisposed();
+                Contract.Ensures(Contract.Result<ReadOnlyCollection<ExportProvider>>() != null);
+
+                return this._providers;
+            }
+        }
+
+        /// <summary>
+        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
+        /// </summary>
+        public void Dispose()
+        {
+            this.Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        /// <summary>
+        /// Releases unmanaged and - optionally - managed resources
+        /// </summary>
+        /// <param name="disposing"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
+        protected virtual void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                if (!this._isDisposed)
+                {
+                    ExportProvider rootProvider = null;
+                    AggregateExportProvider ancestorExportProvider = null;
+                    AggregateExportProvider localExportProvider = null;
+                    ComposablePartExportProvider partExportProvider = null;
+                    CatalogExportProvider catalogExportProvider = null;
+                    ImportEngine importEngine = null;
+
+                    lock(this._lock)
+                    {
+                        if (!this._isDisposed)
+                        {
+                            rootProvider = this._rootProvider;
+                            this._rootProvider = null;
+
+                            localExportProvider = this._localExportProvider;
+                            this._localExportProvider = null;
+
+                            ancestorExportProvider = this._ancestorExportProvider;
+                            this._ancestorExportProvider = null;
+
+                            partExportProvider = this._partExportProvider;
+                            this._partExportProvider = null;
+
+                            catalogExportProvider = this._catalogExportProvider;
+                            this._catalogExportProvider = null;
+
+                            importEngine = this._importEngine;
+                            this._importEngine = null;
+
+                            this._isDisposed = true;
+                        }
+                    }
+
+                    if (rootProvider != null)
+                    {
+                        rootProvider.ExportsChanged -= this.OnExportsChangedInternal;
+                        rootProvider.ExportsChanging -= this.OnExportsChangingInternal;
+                    }
+
+                    if (ancestorExportProvider != null)
+                    {
+                        ancestorExportProvider.Dispose();
+                    }
+
+                    if (localExportProvider != null)
+                    {
+                        localExportProvider.Dispose();
+                    }
+
+                    if (catalogExportProvider != null)
+                    {
+                        catalogExportProvider.Dispose();
+                    }
+
+                    if (partExportProvider != null)
+                    {
+                        partExportProvider.Dispose();
+                    }
+
+                    if (importEngine != null)
+                    {
+                        importEngine.Dispose();
+                    }
+                }
+
+            }
+        }
+  
+        public void Compose(CompositionBatch batch)
+        {
+            Requires.NotNull(batch, "batch");
+            this.ThrowIfDisposed();
+
+            this._partExportProvider.Compose(batch);
+        }
+
+        /// <summary>
+        ///     Releases the <see cref="Export"/> from the <see cref="CompositionContainer"/>. The behavior
+        ///     may vary depending on the implementation of the <see cref="ExportProvider"/> that produced 
+        ///     the <see cref="Export"/> instance. As a general rule non shared exports should be early 
+        ///     released causing them to be detached from the container.
+        ///
+        ///     For example the <see cref="CatalogExportProvider"/> will only release 
+        ///     an <see cref="Export"/> if it comes from a <see cref="ComposablePart"/> that was constructed
+        ///     under a <see cref="CreationPolicy.NonShared" /> context. Release in this context means walking
+        ///     the dependency chain of the <see cref="Export"/>s, detaching references from the container and 
+        ///     calling Dispose on the <see cref="ComposablePart"/>s as needed. If the <see cref="Export"/> 
+        ///     was constructed under a <see cref="CreationPolicy.Shared" /> context the 
+        ///     <see cref="CatalogExportProvider"/> will do nothing as it may be in use by other requestors. 
+        ///     Those will only be detached when the container is itself disposed.
+        /// </summary>
+        /// <param name="export"><see cref="Export"/> that needs to be released.</param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="export"/> is <see langword="null"/>.
+        /// </exception>
+        [SuppressMessage("Microsoft.Performance", "CA1822")]
+        public void ReleaseExport(Export export)
+        {
+            Requires.NotNull(export, "export");
+
+            IDisposable dependency = export as IDisposable;
+
+            if (dependency != null)
+            {
+                dependency.Dispose();
+            }
+        }
+
+        /// <summary>
+        ///     Releases the <see cref="Lazy{T}"/> from the <see cref="CompositionContainer"/>. The behavior
+        ///     may vary depending on the implementation of the <see cref="ExportProvider"/> that produced 
+        ///     the <see cref="Export"/> instance. As a general rule non shared exports should be early 
+        ///     released causing them to be detached from the container.
+        ///
+        ///     For example the <see cref="CatalogExportProvider"/> will only release 
+        ///     an <see cref="Lazy{T}"/> if it comes from a <see cref="ComposablePart"/> that was constructed
+        ///     under a <see cref="CreationPolicy.NonShared" /> context. Release in this context means walking
+        ///     the dependency chain of the <see cref="Export"/>s, detaching references from the container and 
+        ///     calling Dispose on the <see cref="ComposablePart"/>s as needed. If the <see cref="Export"/> 
+        ///     was constructed under a <see cref="CreationPolicy.Shared" /> context the 
+        ///     <see cref="CatalogExportProvider"/> will do nothing as it may be in use by other requestors. 
+        ///     Those will only be detached when the container is itself disposed.
+        /// </summary>
+        /// <param name="export"><see cref="Export"/> that needs to be released.</param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="export"/> is <see langword="null"/>.
+        /// </exception>
+        [SuppressMessage("Microsoft.Performance", "CA1822")]
+        public void ReleaseExport<T>(Lazy<T> export)
+        {
+            Requires.NotNull(export, "export");
+
+            IDisposable dependency = export as IDisposable;
+
+            if (dependency != null)
+            {
+                dependency.Dispose();
+            }
+        }
+
+        /// <summary>
+        ///     Releases a set of <see cref="Export"/>s from the <see cref="CompositionContainer"/>. 
+        ///     See also <see cref="ReleaseExport"/>.
+        /// </summary>
+        /// <param name="exports"><see cref="Export"/>s that need to be released.</param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="exports"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="exports"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        public void ReleaseExports(IEnumerable<Export> exports)
+        {
+            Requires.NotNullOrNullElements(exports, "exports");
+
+            foreach (Export export in exports)
+            {
+                this.ReleaseExport(export);
+            }
+        }
+
+        /// <summary>
+        ///     Releases a set of <see cref="Export"/>s from the <see cref="CompositionContainer"/>. 
+        ///     See also <see cref="ReleaseExport"/>.
+        /// </summary>
+        /// <param name="exports"><see cref="Export"/>s that need to be released.</param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="exports"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="exports"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public void ReleaseExports<T>(IEnumerable<Lazy<T>> exports)
+        {
+            Requires.NotNullOrNullElements(exports, "exports");
+
+            foreach (Lazy<T> export in exports)
+            {
+                this.ReleaseExport(export);
+            }
+        }
+
+        /// <summary>
+        ///     Releases a set of <see cref="Export"/>s from the <see cref="CompositionContainer"/>. 
+        ///     See also <see cref="ReleaseExport"/>.
+        /// </summary>
+        /// <param name="exports"><see cref="Export"/>s that need to be released.</param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="exports"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="exports"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public void ReleaseExports<T, TMetadataView>(IEnumerable<Lazy<T, TMetadataView>> exports)
+        {
+            Requires.NotNullOrNullElements(exports, "exports");
+
+            foreach (Lazy<T, TMetadataView> export in exports)
+            {
+                this.ReleaseExport(export);
+            }
+        }
+
+        /// <summary>
+        ///     Sets the imports of the specified composable part exactly once and they will not
+        ///     ever be recomposed.
+        /// </summary>
+        /// <param name="part">
+        ///     The <see cref="ComposablePart"/> to set the imports.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="part"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ICompositionService"/> has been disposed of.
+        /// </exception>
+        public void SatisfyImportsOnce(ComposablePart part)
+        {
+            this.ThrowIfDisposed();
+            
+            if (this._importEngine == null)
+            {
+                ImportEngine importEngine = new ImportEngine(this, this._compositionOptions);
+                
+                lock(this._lock)
+                {
+                    if (this._importEngine == null)
+                    {
+                        Thread.MemoryBarrier();
+                        this._importEngine = importEngine;
+                        importEngine = null;
+                    }
+                }
+                if(importEngine != null)
+                {
+                    importEngine.Dispose();
+                }
+            }
+            this._importEngine.SatisfyImportsOnce(part);
+        }
+
+        internal void OnExportsChangedInternal(object sender, ExportsChangeEventArgs e)
+        {
+            this.OnExportsChanged(e);
+        }
+
+        internal void OnExportsChangingInternal(object sender, ExportsChangeEventArgs e)
+        {
+            this.OnExportsChanging(e);
+        }
+
+        /// <summary>
+        /// Returns all exports that match the conditions of the specified import.
+        /// </summary>
+        /// <param name="definition">The <see cref="ImportDefinition"/> that defines the conditions of the
+        /// <see cref="Export"/> to get.</param>
+        /// <returns></returns>
+        /// <result>
+        /// An <see cref="IEnumerable{T}"/> of <see cref="Export"/> objects that match
+        /// the conditions defined by <see cref="ImportDefinition"/>, if found; otherwise, an
+        /// empty <see cref="IEnumerable{T}"/>.
+        /// </result>
+        /// <remarks>
+        /// 	<note type="inheritinfo">
+        /// The implementers should not treat the cardinality-related mismatches as errors, and are not
+        /// expected to throw exceptions in those cases.
+        /// For instance, if the import requests exactly one export and the provider has no matching exports or more than one,
+        /// it should return an empty <see cref="IEnumerable{T}"/> of <see cref="Export"/>.
+        /// </note>
+        /// </remarks>
+        protected override IEnumerable<Export> GetExportsCore(ImportDefinition definition, AtomicComposition atomicComposition)
+        {
+            this.ThrowIfDisposed();
+
+            IEnumerable<Export> exports = null;
+
+            object source;
+            if(!definition.Metadata.TryGetValue(CompositionConstants.ImportSourceMetadataName, out source))
+            {
+                source = ImportSource.Any;
+            }
+
+            switch((ImportSource)source)
+            {
+                case ImportSource.Any:
+                    Assumes.NotNull(this._rootProvider);
+                    this._rootProvider.TryGetExports(definition, atomicComposition, out exports);
+                    break;
+                case ImportSource.Local:
+                    Assumes.NotNull(this._localExportProvider);
+                    this._localExportProvider.TryGetExports(definition.RemoveImportSource(), atomicComposition, out exports);
+                    break;
+                case ImportSource.NonLocal:
+                    if(this._ancestorExportProvider != null)
+                    {
+                        this._ancestorExportProvider.TryGetExports(definition.RemoveImportSource(), atomicComposition, out exports);
+                    }
+                    break;
+            }
+
+            return exports;
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionLock.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionLock.cs
new file mode 100644
index 00000000000..4edf3974184
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionLock.cs
@@ -0,0 +1,153 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+#define SINGLETHREADEDLOCKENFORCEMENT
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    // This a a lock class that needs to be held in order to perform any mutation of the parts/parts state in the composition
+    // Today's implementation relies on the AppDomain-wide re-entrant lock for changes on the composition, and a narrow lock for changes in 
+    // the state of the specific ImportEngine
+    // Today we make several assumptions to ensure thread-safety:
+    // 1. Each composition doesn't change lock affinity
+    // 2. Every part of the system that updates the status of the parts (in our case ImportEngine) needs to hold the same wide - lock
+    // 3. State of the import engine that gets accessed outside of the wide lock needs to be accessed in the context of the narrow lock
+    // 4. Narrow lock CAN be taken inside the wide lock
+    // 5. Wide lock CANNOT be taken inside the narrow lock
+    // 6. No 3rd party code will EVER get called inside the narrow lock
+    // Sadly, this means that we WILL be calling 3rd party code under a lock, but as long as the lock is re-entrant and they can't invoke us on anotehr thread
+    // we have no issue, other than potential overlocking
+    internal sealed class CompositionLock : IDisposable
+    {
+        // narrow lock
+        private readonly Lock _stateLock = null;
+        // wide lock
+        private static object _compositionLock = new object();
+
+        private int _isDisposed = 0;
+        private bool _isThreadSafe = false;
+
+        private static readonly EmptyLockHolder _EmptyLockHolder = new EmptyLockHolder();
+
+        public CompositionLock(bool isThreadSafe)
+        {
+            this._isThreadSafe = isThreadSafe;
+            if (isThreadSafe)
+            {
+                this._stateLock = new Lock();
+            }
+        }
+
+        public void Dispose()
+        {
+            if (this._isThreadSafe)
+            {
+                if (Interlocked.CompareExchange(ref this._isDisposed, 1, 0) == 0)
+                {
+                    this._stateLock.Dispose();
+                }
+            }
+        }
+
+        public bool IsThreadSafe
+        {
+            get
+            {
+                return this._isThreadSafe;
+            }
+        }
+
+        private void EnterCompositionLock()
+        {
+#pragma warning disable 618
+            if (this._isThreadSafe)
+            {
+                Monitor.Enter(_compositionLock);
+            }
+#pragma warning restore 618
+        }
+
+        private void ExitCompositionLock()
+        {
+            if (this._isThreadSafe)
+            {
+                Monitor.Exit(_compositionLock);
+            }
+        }
+
+        public IDisposable LockComposition()
+        {
+            if (this._isThreadSafe)
+            {
+                return new CompositionLockHolder(this);
+            }
+            else
+            {
+                return _EmptyLockHolder;
+            }
+        }
+
+        public IDisposable LockStateForRead()
+        {
+            if (this._isThreadSafe)
+            {
+                return new ReadLock(this._stateLock);
+            }
+            else
+            {
+                return _EmptyLockHolder;
+            }            
+        }
+
+        public IDisposable LockStateForWrite()
+        {
+            if (this._isThreadSafe)
+            {
+                return new WriteLock(this._stateLock);
+            }
+            else
+            {
+                return _EmptyLockHolder;
+            }   
+        }
+
+        // NOTE : this should NOT be changed to a struct as ImportEngine relies on it
+        public sealed class CompositionLockHolder : IDisposable
+        {
+            private CompositionLock _lock;
+            private int _isDisposed;
+
+            public CompositionLockHolder(CompositionLock @lock)
+            {
+                this._lock = @lock;
+
+                this._isDisposed = 0;
+                this._lock.EnterCompositionLock();
+            }
+
+            public void Dispose()
+            {
+                if (Interlocked.CompareExchange(ref this._isDisposed, 1, 0) == 0)
+                {
+                    this._lock.ExitCompositionLock();
+                }
+            }
+        }
+
+        private sealed class EmptyLockHolder : IDisposable
+        {
+            public void Dispose()
+            {
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionOptions.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionOptions.cs
new file mode 100644
index 00000000000..fee5081accb
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionOptions.cs
@@ -0,0 +1,21 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    /// <summary>
+    ///     Defines the Constructor settings for export providers.
+    /// </summary>
+    [Flags]
+    public enum CompositionOptions
+    {
+        Default                = 0x0000,
+        DisableSilentRejection = 0x0001,
+        IsThreadSafe           = 0x0002,
+        ExportCompositionService = 0x0004
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionScopeDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionScopeDefinition.cs
new file mode 100644
index 00000000000..382b2dee417
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionScopeDefinition.cs
@@ -0,0 +1,276 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Linq;
+using System.Collections.Generic;
+using System.Diagnostics.Contracts;
+using System.ComponentModel.Composition.Hosting;
+using Microsoft.Internal;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Threading;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    [DebuggerTypeProxy(typeof(CompositionScopeDefinitionDebuggerProxy))]
+    public class CompositionScopeDefinition : ComposablePartCatalog, INotifyComposablePartCatalogChanged
+    {
+        private ComposablePartCatalog _catalog;
+        private IEnumerable<ExportDefinition> _publicSurface = null;
+        private IEnumerable<CompositionScopeDefinition> _children = Enumerable.Empty<CompositionScopeDefinition>();
+        private volatile int _isDisposed = 0;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CompositionScopeDefinition"/> class.
+        /// </summary>
+        protected CompositionScopeDefinition() { }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CompositionScopeDefinition"/> class.
+        /// </summary>
+        /// <param name="catalog">The catalog.</param>
+        /// <param name="children">The children.</param>
+        public CompositionScopeDefinition(ComposablePartCatalog catalog, IEnumerable<CompositionScopeDefinition> children)
+        {
+            Requires.NotNull(catalog, "catalog");
+            Requires.NullOrNotNullElements(children, "children");
+
+            InitializeCompositionScopeDefinition(catalog, children, null);
+        }
+
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CompositionScopeDefinition"/> class.
+        /// </summary>
+        /// <param name="catalog">The catalog.</param>
+        /// <param name="children">The children.</param>
+        /// <param name="publicSurface">The exports that can be used to create new scopes.</param>
+        public CompositionScopeDefinition(ComposablePartCatalog catalog, IEnumerable<CompositionScopeDefinition> children, IEnumerable<ExportDefinition> publicSurface)
+        {
+            Requires.NotNull(catalog, "catalog");
+            Requires.NullOrNotNullElements(children, "children");
+            Requires.NullOrNotNullElements(publicSurface, "publicSurface");
+
+            InitializeCompositionScopeDefinition(catalog, children, publicSurface);
+        }
+
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CompositionScopeDefinition"/> class.
+        /// </summary>
+        /// <param name="catalog">The catalog.</param>
+        /// <param name="children">The children.</param>
+        private void InitializeCompositionScopeDefinition(ComposablePartCatalog catalog, IEnumerable<CompositionScopeDefinition> children, IEnumerable<ExportDefinition> publicSurface)
+        {
+            this._catalog = catalog;
+            if (children != null)
+            {
+                this._children = children.ToArray();
+            }
+            if(publicSurface != null)
+            {
+                this._publicSurface = publicSurface;
+            }
+
+            INotifyComposablePartCatalogChanged notifyCatalog = this._catalog as INotifyComposablePartCatalogChanged;
+            if (notifyCatalog != null)
+            {
+                notifyCatalog.Changed += this.OnChangedInternal;
+                notifyCatalog.Changing += this.OnChangingInternal;
+            }
+        }
+
+        /// <summary>
+        /// Releases unmanaged and - optionally - managed resources
+        /// </summary>
+        /// <param name="disposing"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
+        protected override void Dispose(bool disposing)
+        {
+            try
+            {
+                if (disposing)
+                {
+                    // NOTE : According to http://msdn.microsoft.com/en-us/library/4bw5ewxy.aspx, the warning is bogus when used with Interlocked API.
+#pragma warning disable 420
+                    if (Interlocked.CompareExchange(ref this._isDisposed, 1, 0) == 0)
+#pragma warning restore 420
+                    {
+                        INotifyComposablePartCatalogChanged notifyCatalog = this._catalog as INotifyComposablePartCatalogChanged;
+                        if (notifyCatalog != null)
+                        {
+                            notifyCatalog.Changed -= this.OnChangedInternal;
+                            notifyCatalog.Changing -= this.OnChangingInternal;
+                        }
+                    }
+                }
+            }
+            finally
+            {
+                base.Dispose(disposing);
+            }
+        }
+
+        /// <summary>
+        /// Gets the children.
+        /// </summary>
+        /// <value>The children.</value>
+        public virtual IEnumerable<CompositionScopeDefinition> Children
+        {
+            get
+            {
+                this.ThrowIfDisposed();
+
+                return this._children;
+            }
+        }
+
+        /// <summary>
+        ///     Gets the export definitions that describe the exports surfaced by the CompositionScopedefinition.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="ExportDefinition"/> objects describing
+        ///     the exports surfaced by the <see cref="CompositionScopeDefinition"/>.
+        /// </value>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Overriders of this property must not return <see langword="null"/>.
+        ///     </note>
+        /// </remarks>
+        public virtual IEnumerable<ExportDefinition> PublicSurface
+        {
+            get
+            {
+                this.ThrowIfDisposed();
+                if(this._publicSurface == null)
+                {
+                    return this.SelectMany( (p) => p.ExportDefinitions );
+                }
+
+                return this._publicSurface;
+            }
+        } 
+
+        /// <summary>
+        /// Gets an Enumerator for the ComposablePartDefinitions
+        /// </summary>
+        /// <value>The children.</value>
+        public override IEnumerator<ComposablePartDefinition> GetEnumerator()
+        {
+            return this._catalog.GetEnumerator();
+        }
+
+        /// <summary>
+        /// Returns the export definitions that match the constraint defined by the specified definition.
+        /// </summary>
+        /// <param name="definition">The <see cref="ImportDefinition"/> that defines the conditions of the
+        /// <see cref="ExportDefinition"/> objects to return.</param>
+        /// <returns>
+        /// An <see cref="IEnumerable{T}"/> of <see cref="Tuple{T1, T2}"/> containing the
+        /// <see cref="ExportDefinition"/> objects and their associated
+        /// <see cref="ComposablePartDefinition"/> for objects that match the constraint defined
+        /// by <paramref name="definition"/>.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        /// 	<paramref name="definition"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        /// The <see cref="ComposablePartCatalog"/> has been disposed of.
+        /// </exception>
+        /// <remarks>
+        /// 	<note type="inheritinfo">
+        /// Overriders of this property should never return <see langword="null"/>, if no
+        /// <see cref="ExportDefinition"/> match the conditions defined by
+        /// <paramref name="definition"/>, return an empty <see cref="IEnumerable{T}"/>.
+        /// </note>
+        /// </remarks>
+        public override IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>> GetExports(ImportDefinition definition)
+        {
+            this.ThrowIfDisposed();
+
+            return this._catalog.GetExports(definition);
+        }
+
+        internal IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>> GetExportsFromPublicSurface(ImportDefinition definition)
+        {
+            Assumes.NotNull(definition, "definition");
+
+            var exports = new List<Tuple<ComposablePartDefinition, ExportDefinition>>();
+
+            foreach(var exportDefinition in this.PublicSurface)
+            {
+                if (definition.IsConstraintSatisfiedBy(exportDefinition))
+                {
+                    foreach (var export in this.GetExports(definition))
+                    {
+                        if(export.Item2 == exportDefinition)
+                        {
+                            exports.Add(export);
+                            break;
+                        }
+                    }
+                }
+            }
+            return exports;
+        }
+
+        /// <summary>
+        /// Notify when the contents of the Catalog has changed.
+        /// </summary>
+        public event EventHandler<ComposablePartCatalogChangeEventArgs> Changed;
+
+        /// <summary>
+        /// Notify when the contents of the Catalog is changing.
+        /// </summary>
+        public event EventHandler<ComposablePartCatalogChangeEventArgs> Changing;
+
+        /// <summary>
+        /// Raises the <see cref="E:Changed"/> event.
+        /// </summary>
+        /// <param name="e">The <see cref="System.ComponentModel.Composition.Hosting.ComposablePartCatalogChangeEventArgs"/> instance containing the event data.</param>
+        protected virtual void OnChanged(ComposablePartCatalogChangeEventArgs e)
+        {
+            EventHandler<ComposablePartCatalogChangeEventArgs> changedEvent = this.Changed;
+            if (changedEvent != null)
+            {
+                changedEvent.Invoke(this, e);
+            }
+        }
+
+        /// <summary>
+        /// Raises the <see cref="E:Changing"/> event.
+        /// </summary>
+        /// <param name="e">The <see cref="System.ComponentModel.Composition.Hosting.ComposablePartCatalogChangeEventArgs"/> instance containing the event data.</param>
+        protected virtual void OnChanging(ComposablePartCatalogChangeEventArgs e)
+        {
+            EventHandler<ComposablePartCatalogChangeEventArgs> changingEvent = this.Changing;
+            if (changingEvent != null)
+            {
+                changingEvent.Invoke(this, e);
+            }
+        }
+
+        private void OnChangedInternal(object sender, ComposablePartCatalogChangeEventArgs e)
+        {
+            this.OnChanged(e);
+        }
+
+        private void OnChangingInternal(object sender, ComposablePartCatalogChangeEventArgs e)
+        {
+            this.OnChanging(e);
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed == 1)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionScopeDefinitionDebuggerProxy.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionScopeDefinitionDebuggerProxy.cs
new file mode 100644
index 00000000000..c0d75a65075
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionScopeDefinitionDebuggerProxy.cs
@@ -0,0 +1,49 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    // This proxy is needed to pretty up CompositionScopeDefinitionCatalog.Parts; IQueryable<T> 
+    // instances are not displayed in a very friendly way in the debugger.
+    internal class CompositionScopeDefinitionDebuggerProxy
+    {
+        private readonly CompositionScopeDefinition _compositionScopeDefinition;
+
+        public CompositionScopeDefinitionDebuggerProxy(CompositionScopeDefinition compositionScopeDefinition) 
+        {
+            Requires.NotNull(compositionScopeDefinition, "compositionScopeDefinition");
+
+            this._compositionScopeDefinition = compositionScopeDefinition;
+        }
+
+        public ReadOnlyCollection<ComposablePartDefinition> Parts
+        {
+            get { return this._compositionScopeDefinition.Parts.ToReadOnlyCollection(); }
+        }
+        
+        public IEnumerable<ExportDefinition> PublicSurface
+        {
+            get
+            {
+                return this._compositionScopeDefinition.PublicSurface.ToReadOnlyCollection();
+            }
+        } 
+
+        public virtual IEnumerable<CompositionScopeDefinition> Children
+        {
+            get
+            {
+                return this._compositionScopeDefinition.Children.ToReadOnlyCollection();
+            }
+        }
+
+
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionService.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionService.cs
new file mode 100644
index 00000000000..4e83bb83b5f
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionService.cs
@@ -0,0 +1,73 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Linq;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    /// <summary>
+    ///     A mutable collection of <see cref="ComposablePartCatalog"/>s.  
+    /// </summary>
+    /// <remarks>
+    ///     This type is thread safe.
+    /// </remarks>
+    public class CompositionService : ICompositionService, IDisposable
+    {
+        private CompositionContainer _compositionContainer = null;
+        private INotifyComposablePartCatalogChanged _notifyCatalog = null;
+
+        internal CompositionService(ComposablePartCatalog composablePartCatalog)
+        {
+            Assumes.NotNull(composablePartCatalog);
+            this._notifyCatalog = composablePartCatalog as INotifyComposablePartCatalogChanged;
+            try
+            {
+                if(this._notifyCatalog != null)
+                {
+                    this._notifyCatalog.Changing += this.OnCatalogChanging;
+                }
+
+                var compositionOptions = CompositionOptions.DisableSilentRejection | CompositionOptions.IsThreadSafe | CompositionOptions.ExportCompositionService;
+                var compositionContainer = new CompositionContainer(composablePartCatalog, compositionOptions);
+    
+                this._compositionContainer = compositionContainer;
+            }
+            catch
+            {
+                if(this._notifyCatalog != null)
+                {
+                    this._notifyCatalog.Changing -= this.OnCatalogChanging;
+                }
+                throw;
+            }
+        }
+
+        public void SatisfyImportsOnce(ComposablePart part)
+        {
+            Requires.NotNull(part, "part");
+            Assumes.NotNull(this._compositionContainer);
+            this._compositionContainer.SatisfyImportsOnce(part);
+        }
+
+        public void Dispose()
+        {
+            Assumes.NotNull(this._compositionContainer);
+            
+            // Delegates are cool there is no concern if you try to remove an item from them and they don't exist
+            if (this._notifyCatalog != null)
+            {
+                this._notifyCatalog.Changing -= this.OnCatalogChanging;
+            }
+            this._compositionContainer.Dispose();
+        }
+
+        private void OnCatalogChanging(object sender, ComposablePartCatalogChangeEventArgs e)
+        {
+            throw new ChangeRejectedException(Strings.NotSupportedCatalogChanges);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionServices.cs
new file mode 100644
index 00000000000..a68f8639ebe
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/CompositionServices.cs
@@ -0,0 +1,662 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.ComponentModel.Composition.AttributedModel;
+using System.ComponentModel.Composition.Primitives;
+using System.Globalization;
+using System.Linq;
+using System.Reflection;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using System.Collections.ObjectModel;
+using System.ComponentModel.Composition.ReflectionModel;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    internal static class CompositionServices
+    {
+        internal static readonly Type InheritedExportAttributeType = typeof(InheritedExportAttribute);
+        internal static readonly Type ExportAttributeType = typeof(ExportAttribute);
+        internal static readonly Type AttributeType = typeof(Attribute);
+        internal static readonly Type ObjectType = typeof(object);
+
+        private static readonly string[] reservedMetadataNames = new string[]
+        {
+            CompositionConstants.PartCreationPolicyMetadataName
+        };  
+
+        internal static Type GetDefaultTypeFromMember(this MemberInfo member)
+        {
+            Assumes.NotNull(member);
+
+            switch (member.MemberType)
+            {
+                case MemberTypes.Property:
+                    return ((PropertyInfo)member).PropertyType;
+
+                case MemberTypes.NestedType:
+                case MemberTypes.TypeInfo:
+                    return ((Type)member);
+
+                case MemberTypes.Field:
+                default:
+                    Assumes.IsTrue(member.MemberType == MemberTypes.Field);
+                    return ((FieldInfo)member).FieldType;
+            }
+        }
+
+        internal static Type AdjustSpecifiedTypeIdentityType(this Type specifiedContractType, MemberInfo member)
+        {
+            if (member.MemberType == MemberTypes.Method)
+            {
+                return specifiedContractType;
+            }
+            else
+            {
+                return specifiedContractType.AdjustSpecifiedTypeIdentityType(member.GetDefaultTypeFromMember());
+            }
+        }
+
+        internal static Type AdjustSpecifiedTypeIdentityType(this Type specifiedContractType, Type memberType)
+        {
+            Assumes.NotNull(specifiedContractType);
+
+            if ((memberType != null) && memberType.IsGenericType && specifiedContractType.IsGenericType)
+            {
+                // if the memeber type is closed and the specified contract type is open and they have exatly the same number of parameters
+                // we will close the specfied contract type
+                if (specifiedContractType.ContainsGenericParameters && !memberType.ContainsGenericParameters)
+                {
+                    var typeGenericArguments = memberType.GetGenericArguments();
+                    var metadataTypeGenericArguments = specifiedContractType.GetGenericArguments();
+
+                    if (typeGenericArguments.Length == metadataTypeGenericArguments.Length)
+                    {
+                        return specifiedContractType.MakeGenericType(typeGenericArguments);
+                    }
+                }
+                // if both member type and the contract type are open generic types, make sure that their parameters are ordered the same way 
+                else if(specifiedContractType.ContainsGenericParameters && memberType.ContainsGenericParameters)
+                {
+                    var memberGenericParameters = memberType.GetPureGenericParameters();
+                    if (specifiedContractType.GetPureGenericArity() == memberGenericParameters.Count)
+                    {
+                        return specifiedContractType.GetGenericTypeDefinition().MakeGenericType(memberGenericParameters.ToArray());
+                    }
+                }
+            }
+
+            return specifiedContractType;
+        }
+
+        private static string AdjustTypeIdentity(string originalTypeIdentity, Type typeIdentityType)
+        {
+            return GenericServices.GetGenericName(originalTypeIdentity, GenericServices.GetGenericParametersOrder(typeIdentityType), GenericServices.GetPureGenericArity(typeIdentityType));
+        }
+
+        internal static void GetContractInfoFromExport(this MemberInfo member, ExportAttribute export, out Type typeIdentityType, out string contractName)
+        {
+            typeIdentityType = member.GetTypeIdentityTypeFromExport(export);
+            if (!string.IsNullOrEmpty(export.ContractName))
+            {
+                contractName = export.ContractName;
+            }
+            else
+            {
+                contractName = member.GetTypeIdentityFromExport(typeIdentityType);
+            }
+        }
+
+
+        internal static string GetTypeIdentityFromExport(this MemberInfo member, Type typeIdentityType)
+        {   
+            if (typeIdentityType != null)
+            {
+                string typeIdentity = AttributedModelServices.GetTypeIdentity(typeIdentityType);
+                if (typeIdentityType.ContainsGenericParameters)
+                {
+                    typeIdentity = AdjustTypeIdentity(typeIdentity, typeIdentityType);
+                }
+                return typeIdentity;
+            }
+            else
+            {
+                MethodInfo method = member as MethodInfo;
+                Assumes.NotNull(method);
+                return AttributedModelServices.GetTypeIdentity(method);
+            }
+        }
+
+        private static Type GetTypeIdentityTypeFromExport(this MemberInfo member, ExportAttribute export)
+        {
+            if (export.ContractType != null)
+            {
+                return export.ContractType.AdjustSpecifiedTypeIdentityType(member);
+            }
+            else
+            {
+                return (member.MemberType != MemberTypes.Method) ? member.GetDefaultTypeFromMember() : null;
+            }
+        }
+
+        internal static bool IsContractNameSameAsTypeIdentity(this ExportAttribute export)
+        {
+            return string.IsNullOrEmpty(export.ContractName);
+        }
+
+
+        internal static Type GetContractTypeFromImport(this IAttributedImport import, ImportType importType)
+        {
+            if (import.ContractType != null)
+            {
+                return import.ContractType.AdjustSpecifiedTypeIdentityType(importType.ContractType);
+            }
+
+            return importType.ContractType;
+        }
+
+        internal static string GetContractNameFromImport(this IAttributedImport import, ImportType importType)
+        {
+            if (!string.IsNullOrEmpty(import.ContractName))
+            {
+                return import.ContractName;
+            }
+
+            Type contractType = import.GetContractTypeFromImport(importType);
+
+            return AttributedModelServices.GetContractName(contractType); 
+        }
+
+        internal static string GetTypeIdentityFromImport(this IAttributedImport import, ImportType importType)
+        {
+            Type contractType = import.GetContractTypeFromImport(importType);
+
+            // For our importers we treat object as not having a type identity
+            if (contractType == CompositionServices.ObjectType)
+            {
+                return null;
+            }
+
+            return AttributedModelServices.GetTypeIdentity(contractType); 
+        }
+
+        internal static IDictionary<string, object> GetPartMetadataForType(this Type type, CreationPolicy creationPolicy)
+        {
+            IDictionary<string, object> dictionary = new Dictionary<string, object>(StringComparers.MetadataKeyNames);
+
+            if (creationPolicy != CreationPolicy.Any)
+            {
+                dictionary.Add(CompositionConstants.PartCreationPolicyMetadataName, creationPolicy);
+            }
+
+            foreach (PartMetadataAttribute partMetadata in type.GetAttributes<PartMetadataAttribute>())
+            {
+                if (reservedMetadataNames.Contains(partMetadata.Name, StringComparers.MetadataKeyNames) 
+                    || dictionary.ContainsKey(partMetadata.Name))
+                {
+                    // Perhaps we should log an error here so that people know this value is being ignored.
+                    continue;
+                }
+
+                dictionary.Add(partMetadata.Name, partMetadata.Value);
+            }
+
+            // metadata for generic types
+            if (type.ContainsGenericParameters)
+            {
+                // Register the part as generic
+                dictionary.Add(CompositionConstants.IsGenericPartMetadataName, true);
+
+                // Add arity
+                Type[] genericArguments = type.GetGenericArguments();
+                dictionary.Add(CompositionConstants.GenericPartArityMetadataName, genericArguments.Length);
+
+                // add constraints
+                bool hasConstraints = false;
+                object[] genericParameterConstraints = new object[genericArguments.Length];
+                GenericParameterAttributes[] genericParameterAttributes = new GenericParameterAttributes[genericArguments.Length];
+                for (int i=0; i< genericArguments.Length ; i++)
+                {
+                    Type genericArgument = genericArguments[i];
+
+                    Type[] constraints = genericArgument.GetGenericParameterConstraints();
+                    if (constraints.Length == 0)
+                    {
+                        constraints = null;
+                    }
+
+                    GenericParameterAttributes attributes = genericArgument.GenericParameterAttributes;
+
+                    if ((constraints != null) || (attributes != GenericParameterAttributes.None))
+                    {
+                        genericParameterConstraints[i] = constraints;
+                        genericParameterAttributes[i] = attributes;
+                        hasConstraints = true;
+                    }
+                }
+
+                if (hasConstraints)
+                {
+                    dictionary.Add(CompositionConstants.GenericParameterConstraintsMetadataName, genericParameterConstraints);
+                    dictionary.Add(CompositionConstants.GenericParameterAttributesMetadataName, genericParameterAttributes);
+                }
+            }
+
+            if (dictionary.Count == 0)
+            {
+                return MetadataServices.EmptyMetadata;
+            }
+            else
+            {
+                return dictionary;
+            }
+        }
+
+        internal static void TryExportMetadataForMember(this MemberInfo member, out IDictionary<string, object> dictionary)
+        {
+            dictionary = new Dictionary<string, object>();
+
+            foreach (var attr in member.GetAttributes<Attribute>())
+            {
+                var provider = attr as ExportMetadataAttribute;
+
+                if (provider != null)
+                {
+                    if (reservedMetadataNames.Contains(provider.Name, StringComparers.MetadataKeyNames))
+                    {
+                        throw ExceptionBuilder.CreateDiscoveryException(Strings.Discovery_ReservedMetadataNameUsed, member.GetDisplayName(), provider.Name);
+                    }
+
+                    // we pass "null" for valueType which would make it inferred. We don;t have additional type information when metadata
+                    // goes through the ExportMetadataAttribute path
+                    if (!dictionary.TryContributeMetadataValue(provider.Name, provider.Value, null, provider.IsMultiple))
+                    {
+                        throw ExceptionBuilder.CreateDiscoveryException(Strings.Discovery_DuplicateMetadataNameValues, member.GetDisplayName(), provider.Name);
+                    }
+                }
+                else
+                {
+                    Type attrType = attr.GetType();
+                    if ((attrType != CompositionServices.ExportAttributeType) && attrType.IsAttributeDefined<MetadataAttributeAttribute>(true))
+                    {
+                        bool allowsMultiple = false;
+                        AttributeUsageAttribute usage = attrType.GetFirstAttribute<AttributeUsageAttribute>(true);
+
+                        if (usage != null)
+                        {
+                            allowsMultiple = usage.AllowMultiple;
+                        }
+
+                        foreach (PropertyInfo pi in attrType.GetProperties())
+                        {
+                            if (pi.DeclaringType == CompositionServices.ExportAttributeType || pi.DeclaringType == CompositionServices.AttributeType)
+                            {
+                                // Don't contribute metadata properies from the base attribute types.
+                                continue;
+                            }
+
+                            if (reservedMetadataNames.Contains(pi.Name, StringComparers.MetadataKeyNames))
+                            {
+                                throw ExceptionBuilder.CreateDiscoveryException(Strings.Discovery_ReservedMetadataNameUsed, member.GetDisplayName(), provider.Name);
+                            }
+
+                            object value = pi.GetValue(attr, null);
+
+                            if (value != null && !IsValidAttributeType(value.GetType()))
+                            {
+                                throw ExceptionBuilder.CreateDiscoveryException(Strings.Discovery_MetadataContainsValueWithInvalidType, pi.GetDisplayName(), value.GetType().GetDisplayName());
+                            }
+
+                            if (!dictionary.TryContributeMetadataValue(pi.Name, value, pi.PropertyType, allowsMultiple))
+                            {
+                                throw ExceptionBuilder.CreateDiscoveryException(Strings.Discovery_DuplicateMetadataNameValues, member.GetDisplayName(), pi.Name);
+                            }
+                        }
+                    }
+                }
+            }
+
+            // Need Keys.ToArray because we alter the dictionary in the loop
+            foreach (var key in dictionary.Keys.ToArray())
+            {
+                var list = dictionary[key] as MetadataList;
+                if (list != null)
+                {
+                    dictionary[key] = list.ToArray();
+                }
+            }
+
+            return;
+        }
+
+        private static bool TryContributeMetadataValue(this IDictionary<string, object> dictionary, string name, object value, Type valueType, bool allowsMultiple)
+        {
+            object metadataValue;
+            if (!dictionary.TryGetValue(name, out metadataValue))
+            {
+                if (allowsMultiple)
+                {
+                    var list = new MetadataList();
+                    list.Add(value, valueType);
+                    value = list;
+                }
+
+                dictionary.Add(name, value);
+            }
+            else
+            {
+                var list = metadataValue as MetadataList;
+                if (!allowsMultiple || list == null)
+                {
+                    // Either single value already found when should be multiple
+                    // or a duplicate name already exists
+                    dictionary.Remove(name);
+                    return false;
+                }
+
+                list.Add(value, valueType);
+            }
+            return true;
+        }
+
+        private class MetadataList
+        {
+            private Type _arrayType = null;
+            private bool _containsNulls = false;
+            private static readonly Type ObjectType = typeof(object);
+            private static readonly Type TypeType = typeof(Type);
+            private Collection<object> _innerList = new Collection<object>();
+
+            public void Add(object item, Type itemType)
+            {
+                this._containsNulls |= (item == null);
+
+                // if we've been passed typeof(object), we basically have no type inmformation
+                if (itemType == ObjectType)
+                {
+                    itemType = null;
+                }
+
+                // if we have no type information, get it from the item, if we can
+                if ((itemType == null) && (item != null))
+                {
+                    itemType = item.GetType();
+                }
+
+                // Types are special, because the are abstract classes, so if the item casts to Type, we assume System.Type
+                if (item is Type)
+                {
+                    itemType = TypeType;
+                }
+
+                // only try to call this if we got a meaningful type
+                if (itemType != null)
+                {
+                    this.InferArrayType(itemType);
+                }
+
+                this._innerList.Add(item);
+            }
+
+            private void InferArrayType(Type itemType)
+            {
+                Assumes.NotNull(itemType);
+
+                if (this._arrayType == null)
+                {
+                    // this is the first typed element we've been given, it sets the type of the array
+                    this._arrayType = itemType;
+                }
+                else
+                {
+                    // if there's a disagreement on the array type, we flip to Object
+                    // NOTE : we can try to do better in the future to find common base class, but given that we support very limited set of types
+                    // in metadata right now, it's a moot point
+                    if (this._arrayType != itemType)
+                    {
+                        this._arrayType = ObjectType;
+                    }
+                }
+            }
+
+            public Array ToArray()
+            {
+                if (this._arrayType == null)
+                {
+                    // if the array type has not been set, assume Object 
+                    this._arrayType = ObjectType;
+                }
+                else if (this._containsNulls && this._arrayType.IsValueType)
+                {
+                    // if the array type is a value type and we have seen nulls, then assume Object
+                    this._arrayType = ObjectType;
+                }
+
+                Array array = Array.CreateInstance(this._arrayType, this._innerList.Count);
+
+                for(int i = 0; i < array.Length; i++)
+                {
+                    array.SetValue(this._innerList[i], i);
+                }
+                return array;
+            }
+        }
+
+        //UNDONE: Need to add these warnings somewhere...Dev10:472538 should address this.
+        //internal static CompositionResult MatchRequiredMetadata(this IDictionary<string, object> metadata, IEnumerable<string> requiredMetadata, string contractName)
+        //{
+        //    Assumes.IsTrue(metadata != null);
+
+        //    var result = CompositionResult.SucceededResult;
+
+        //    var missingMetadata = (requiredMetadata == null) ? null : requiredMetadata.Except<string>(metadata.Keys);
+        //    if (missingMetadata != null && missingMetadata.Any())
+        //    {
+        //        result = result.MergeIssue(
+        //            CompositionError.CreateIssueAsWarning(CompositionErrorId.RequiredMetadataNotFound,
+        //            Strings.RequiredMetadataNotFound,
+        //            contractName,
+        //            string.Join(", ", missingMetadata.ToArray())));
+
+        //        return new CompositionResult(false, result.Issues);
+        //    }
+
+        //    return result;
+        //}
+
+        internal static IEnumerable<KeyValuePair<string, Type>> GetRequiredMetadata(Type metadataViewType)
+        {
+            if ((metadataViewType == null) ||
+                ExportServices.IsDefaultMetadataViewType(metadataViewType) ||
+                ExportServices.IsDictionaryConstructorViewType(metadataViewType) ||
+                !metadataViewType.IsInterface)
+            {
+                return Enumerable.Empty<KeyValuePair<string, Type>>();
+            }
+
+            // A metadata view is required to be an Intrerface, and therefore only properties are allowed
+            List<PropertyInfo> properties = metadataViewType.GetAllProperties().
+                Where(property => property.GetFirstAttribute<DefaultValueAttribute>() == null).
+                ToList();
+
+            // NOTE : this is a carefully found balance between eager and delay-evaluation - the properties are filtered once and upfront
+            // whereas the key/Type pairs are created every time. The latter is fine as KVPs are structs and as such copied on access regardless.
+            // This also allows us to avoid creation of List<KVP> which - at least according to FxCop - leads to isues with NGEN
+            return properties.Select(property => new KeyValuePair<string, Type>(property.Name, property.PropertyType));
+        }
+
+        internal static IDictionary<string, object> GetImportMetadata(ImportType importType, IAttributedImport attributedImport)
+        {
+            return GetImportMetadata(importType.ContractType, attributedImport);
+        }
+
+        internal static IDictionary<string, object> GetImportMetadata(Type type, IAttributedImport attributedImport)
+        {
+            Dictionary<string, object> metadata = null;
+
+            if (type.IsGenericType)
+            {
+                metadata = new Dictionary<string, object>();
+                
+                if (type.ContainsGenericParameters)
+                {
+                    metadata[CompositionConstants.GenericImportParametersOrderMetadataName] = GenericServices.GetGenericParametersOrder(type);
+                }
+                else
+                {
+                    metadata[CompositionConstants.GenericContractMetadataName] = ContractNameServices.GetTypeIdentity(type.GetGenericTypeDefinition());
+                    metadata[CompositionConstants.GenericParametersMetadataName] = type.GetGenericArguments();
+                }
+            }
+
+            // Default value is ImportSource.Any
+            if(attributedImport != null && attributedImport.Source != ImportSource.Any)
+            {
+                if(metadata == null)
+                {
+                    metadata = new Dictionary<string, object>();
+                }
+                metadata[CompositionConstants.ImportSourceMetadataName] = attributedImport.Source;
+            }
+
+            if(metadata != null)
+            {
+                return metadata.AsReadOnly();
+            }
+            else
+            {
+                return MetadataServices.EmptyMetadata;
+            }
+        }
+
+        internal static object GetExportedValueFromComposedPart(ImportEngine engine, ComposablePart part, ExportDefinition definition)
+        {
+            if (engine != null)
+            {
+                try
+                {
+                    engine.SatisfyImports(part);
+                }
+                catch (CompositionException ex)
+                {
+                    throw ExceptionBuilder.CreateCannotGetExportedValue(part, definition, ex);
+                }
+            }
+
+            try
+            {
+                return part.GetExportedValue(definition);
+            }
+            catch (ComposablePartException ex)
+            {
+                throw ExceptionBuilder.CreateCannotGetExportedValue(part, definition, ex);
+            }
+        }
+        
+        internal static bool IsRecomposable(this ComposablePart part)
+        {
+            return part.ImportDefinitions.Any(import => import.IsRecomposable);
+        }
+
+        internal static CompositionResult TryInvoke(Action action)
+        {
+            try
+            {
+                action();
+                return CompositionResult.SucceededResult;
+            }
+            catch (CompositionException ex)
+            {
+                return new CompositionResult(ex.Errors);
+            }
+        }
+
+        internal static CompositionResult TryFire<TEventArgs>(EventHandler<TEventArgs> _delegate, object sender, TEventArgs e)
+            where TEventArgs : EventArgs
+        {
+            CompositionResult result = CompositionResult.SucceededResult;
+            foreach (EventHandler<TEventArgs> _subscriber in _delegate.GetInvocationList())
+            {
+                try
+                {
+                    _subscriber.Invoke(sender, e);
+                }
+                catch (CompositionException ex)
+                {
+                    result = result.MergeErrors(ex.Errors);
+                }
+            }
+
+            return result;
+        }
+
+        internal static CreationPolicy GetRequiredCreationPolicy(this ImportDefinition definition)
+        {
+            ContractBasedImportDefinition contractDefinition = definition as ContractBasedImportDefinition;
+
+            if (contractDefinition != null)
+            {
+                return contractDefinition.RequiredCreationPolicy;
+            }
+
+            return CreationPolicy.Any;
+        }
+
+        /// <summary>
+        ///     Returns a value indicating whether cardinality is 
+        ///     <see cref="ImportCardinality.ZeroOrOne"/> or 
+        ///     <see cref="ImportCardinality.ExactlyOne"/>.
+        /// </summary>
+        internal static bool IsAtMostOne(this ImportCardinality cardinality)
+        {
+            return cardinality == ImportCardinality.ZeroOrOne || cardinality == ImportCardinality.ExactlyOne;
+        }
+
+        private static bool IsValidAttributeType(Type type)
+        {
+            return IsValidAttributeType(type, true);
+        }
+
+        private static bool IsValidAttributeType(Type type, bool arrayAllowed)
+        {
+            Assumes.NotNull(type);
+            // Definitions of valid attribute type taken from C# 3.0 Specification section 17.1.3.
+
+            // One of the following types: bool, byte, char, double, float, int, long, sbyte, short, string, uint, ulong, ushort.
+            if (type.IsPrimitive)
+            {
+                return true;
+            }
+
+            if (type == typeof(string))
+            {
+                return true;
+            }
+
+            // An enum type, provided it has public accessibility and the types in which it is nested (if any) also have public accessibility 
+            if (type.IsEnum && type.IsVisible)
+            {
+                return true;
+            }
+
+            if (typeof(Type).IsAssignableFrom(type))
+            {
+                return true;
+            }
+
+            // Single-dimensional arrays of the above types.
+            if (arrayAllowed && type.IsArray && 
+                type.GetArrayRank() == 1 &&
+                IsValidAttributeType(type.GetElementType(), false))
+            {
+                return true;
+            }
+
+            return false;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/DirectoryCatalog.DirectoryCatalogDebuggerProxy.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/DirectoryCatalog.DirectoryCatalogDebuggerProxy.cs
new file mode 100644
index 00000000000..3535021128f
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/DirectoryCatalog.DirectoryCatalogDebuggerProxy.cs
@@ -0,0 +1,77 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.ObjectModel;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Linq;
+using System.Reflection;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    partial class DirectoryCatalog
+    {
+        internal class DirectoryCatalogDebuggerProxy
+        {
+            private readonly DirectoryCatalog _catalog;
+
+            public DirectoryCatalogDebuggerProxy(DirectoryCatalog catalog)
+            {
+                Requires.NotNull(catalog, "catalog");
+
+                this._catalog = catalog;
+            }
+
+            public ReadOnlyCollection<Assembly> Assemblies
+            {
+                get
+                {
+                    return this._catalog._assemblyCatalogs.Values.Select(catalog => catalog.Assembly)
+                                                                 .ToReadOnlyCollection();
+                }
+            }
+
+#if FEATURE_REFLECTIONCONTEXT
+            public ReflectionContext ReflectionContext
+            {
+                get
+                {
+                    return this._catalog._reflectionContext;
+                }
+            }
+#endif //FEATURE_REFLECTIONCONTEXT
+
+            public string SearchPattern
+            {
+                get { return this._catalog.SearchPattern; }
+            }
+
+            public string Path
+            {
+                get { return this._catalog._path; }
+            }
+
+            public string FullPath
+            {
+                get { return this._catalog._fullPath; }
+            }
+
+            public ReadOnlyCollection<string> LoadedFiles
+            {
+                get { return this._catalog._loadedFiles; }
+            }
+
+            public ReadOnlyCollection<ComposablePartDefinition> Parts
+            {
+                // NOTE: This shouldn't be cached, so that on every query of
+                // the current value of the underlying catalog is respected.
+                // We use ReadOnlyCollection as arrays do not have the 
+                // appropriate debugger display attributes applied to them.
+                get { return this._catalog.Parts.ToReadOnlyCollection(); }
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/DirectoryCatalog.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/DirectoryCatalog.cs
new file mode 100644
index 00000000000..bb96f389126
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/DirectoryCatalog.cs
@@ -0,0 +1,821 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.ComponentModel.Composition.Diagnostics;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Globalization;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using IOPath = System.IO.Path;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    [DebuggerTypeProxy(typeof(DirectoryCatalogDebuggerProxy))]
+    public partial class DirectoryCatalog : ComposablePartCatalog, INotifyComposablePartCatalogChanged, ICompositionElement
+    {
+        private readonly Lock _thisLock = new Lock();
+        private readonly ICompositionElement _definitionOrigin = null;
+        private ComposablePartCatalogCollection _catalogCollection;
+        private Dictionary<string, AssemblyCatalog> _assemblyCatalogs;
+        private volatile bool _isDisposed = false;
+        private string _path;
+        private string _fullPath;
+        private string _searchPattern;
+        private ReadOnlyCollection<string> _loadedFiles;
+
+#if FEATURE_REFLECTIONCONTEXT
+        private readonly ReflectionContext _reflectionContext = null;
+#endif //FEATURE_REFLECTIONCONTEXT
+
+        /// <summary>
+        ///     Creates a catalog of <see cref="ComposablePartDefinition"/>s based on all the *.dll files 
+        ///     in the given directory path.
+        ///
+        ///     Possible exceptions that can be thrown are any that <see cref="Directory.GetFiles(string, string)"/> or 
+        ///     <see cref="Assembly.Load(AssemblyName)"/> can throw.
+        /// </summary>
+        /// <param name="path">
+        ///     Path to the directory to scan for assemblies to add to the catalog.
+        ///     The path needs to be absolute or relative to <see cref="AppDomain.BaseDirectory"/>
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     If <paramref name="path"/> is a zero-length string, contains only white space, or 
+        ///     contains one or more implementation-specific invalid characters.
+        /// </exception>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="path"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="DirectoryNotFoundException">
+        ///     The specified <paramref name="path"/> is invalid (for example, it is on an unmapped drive). 
+        /// </exception>
+        /// <exception cref="PathTooLongException">
+        ///     The specified <paramref name="path"/>, file name, or both exceed the system-defined maximum length. 
+        ///     For example, on Windows-based platforms, paths must be less than 248 characters and file names must 
+        ///     be less than 260 characters. 
+        /// </exception>
+        /// <exception cref="UnauthorizedAccessException">
+        ///     The caller does not have the required permission. 
+        /// </exception>
+        public DirectoryCatalog(string path)
+            : this(path, "*.dll")
+        {
+        }
+
+#if FEATURE_REFLECTIONCONTEXT
+        /// <summary>
+        ///     Creates a catalog of <see cref="ComposablePartDefinition"/>s based on all the *.dll files 
+        ///     in the given directory path.
+        ///
+        ///     Possible exceptions that can be thrown are any that <see cref="Directory.GetFiles(string, string)"/> or 
+        ///     <see cref="Assembly.Load(AssemblyName)"/> can throw.
+        /// </summary>
+        /// <param name="path">
+        ///     Path to the directory to scan for assemblies to add to the catalog.
+        ///     The path needs to be absolute or relative to <see cref="AppDomain.BaseDirectory"/>
+        /// </param>
+        /// <param name="reflectionContext">
+        ///     The <see cref="ReflectionContext"/> a context used by the catalog when 
+        ///     interpreting the types to inject attributes into the type definition.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     If <paramref name="path"/> is a zero-length string, contains only white space, or 
+        ///     contains one or more implementation-specific invalid characters.
+        /// </exception>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="path"/> is <see langword="null"/> or
+        ///     <paramref name="reflectionContext"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="DirectoryNotFoundException">
+        ///     The specified <paramref name="path"/> is invalid (for example, it is on an unmapped drive). 
+        /// </exception>
+        /// <exception cref="PathTooLongException">
+        ///     The specified <paramref name="path"/>, file name, or both exceed the system-defined maximum length. 
+        ///     For example, on Windows-based platforms, paths must be less than 248 characters and file names must 
+        ///     be less than 260 characters. 
+        /// </exception>
+        /// <exception cref="UnauthorizedAccessException">
+        ///     The caller does not have the required permission. 
+        /// </exception>
+        public DirectoryCatalog(string path, ReflectionContext reflectionContext)
+            : this(path, "*.dll", reflectionContext)
+        {
+        }
+#endif //FEATURE_REFLECTIONCONTEXT
+
+        /// <summary>
+        ///     Creates a catalog of <see cref="ComposablePartDefinition"/>s based on all the *.dll files 
+        ///     in the given directory path.
+        ///
+        ///     Possible exceptions that can be thrown are any that <see cref="Directory.GetFiles(string, string)"/> or 
+        ///     <see cref="Assembly.Load(AssemblyName)"/> can throw.
+        /// </summary>
+        /// <param name="path">
+        ///     Path to the directory to scan for assemblies to add to the catalog.
+        ///     The path needs to be absolute or relative to <see cref="AppDomain.BaseDirectory"/>
+        /// </param>
+        /// <param name="definitionOrigin">
+        ///     The <see cref="ICompositionElement"/> CompositionElement used by Diagnostics to identify the source for parts.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     If <paramref name="path"/> is a zero-length string, contains only white space, or 
+        ///     contains one or more implementation-specific invalid characters.
+        /// </exception>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="path"/> is <see langword="null"/> or
+        ///     <paramref name="definitionOrigin"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="DirectoryNotFoundException">
+        ///     The specified <paramref name="path"/> is invalid (for example, it is on an unmapped drive). 
+        /// </exception>
+        /// <exception cref="PathTooLongException">
+        ///     The specified <paramref name="path"/>, file name, or both exceed the system-defined maximum length. 
+        ///     For example, on Windows-based platforms, paths must be less than 248 characters and file names must 
+        ///     be less than 260 characters. 
+        /// </exception>
+        /// <exception cref="UnauthorizedAccessException">
+        ///     The caller does not have the required permission. 
+        /// </exception>
+        public DirectoryCatalog(string path, ICompositionElement definitionOrigin) 
+            : this(path, "*.dll", definitionOrigin)
+        {
+        }
+
+#if FEATURE_REFLECTIONCONTEXT
+        /// <summary>
+        ///     Creates a catalog of <see cref="ComposablePartDefinition"/>s based on all the given searchPattern 
+        ///     over the files in the given directory path.
+        ///     
+        ///     Possible exceptions that can be thrown are any that <see cref="Directory.GetFiles(string, string)"/> or 
+        ///     <see cref="Assembly.Load(AssemblyName)"/> can throw.
+        /// </summary>
+        /// <param name="path">
+        ///     Path to the directory to scan for assemblies to add to the catalog.
+        ///     The path needs to be absolute or relative to <see cref="AppDomain.BaseDirectory"/>
+        /// </param>
+        /// <param name="reflectionContext">
+        ///     The <see cref="ReflectionContext"/> a context used by the catalog when 
+        ///     interpreting the types to inject attributes into the type definition.
+        /// </param>
+        /// <param name="definitionOrigin">
+        ///     The <see cref="ICompositionElement"/> CompositionElement used by Diagnostics to identify the source for parts.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     If <paramref name="path"/> is a zero-length string, contains only white space 
+        ///     does not contain a valid pattern. 
+        /// </exception>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="path"/> is <see langword="null"/> or
+        ///     <paramref name="reflectionContext"/> is <see langword="null"/> or
+        ///     <paramref name="definitionOrigin"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="DirectoryNotFoundException">
+        ///     The specified <paramref name="path"/> is invalid (for example, it is on an unmapped drive). 
+        /// </exception>
+        /// <exception cref="PathTooLongException">
+        ///     The specified <paramref name="path"/>, file name, or both exceed the system-defined maximum length. 
+        ///     For example, on Windows-based platforms, paths must be less than 248 characters and file names must 
+        ///     be less than 260 characters. 
+        /// </exception>
+        /// <exception cref="UnauthorizedAccessException">
+        ///     The caller does not have the required permission. 
+        /// </exception>
+        public DirectoryCatalog(string path, ReflectionContext reflectionContext, ICompositionElement definitionOrigin)
+            : this(path, "*.dll", reflectionContext, definitionOrigin)
+        {
+        }
+#endif //FEATURE_REFLECTIONCONTEXT
+
+        /// <summary>
+        ///     Creates a catalog of <see cref="ComposablePartDefinition"/>s based on all the *.dll files 
+        ///     in the given directory path.
+        ///
+        ///     Possible exceptions that can be thrown are any that <see cref="Directory.GetFiles(string, string)"/> or 
+        ///     <see cref="Assembly.Load(AssemblyName)"/> can throw.
+        /// </summary>
+        /// <param name="path">
+        ///     Path to the directory to scan for assemblies to add to the catalog.
+        ///     The path needs to be absolute or relative to <see cref="AppDomain.BaseDirectory"/>
+        /// </param>
+        /// <param name="searchPattern">
+        ///     Any valid searchPattern that <see cref="Directory.GetFiles(string, string)"/> will accept.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     If <paramref name="path"/> is a zero-length string, contains only white space, or 
+        ///     contains one or more implementation-specific invalid characters. Or <paramref name="searchPattern"/> 
+        ///     does not contain a valid pattern. 
+        /// </exception>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="path"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="DirectoryNotFoundException">
+        ///     The specified <paramref name="path"/> is invalid (for example, it is on an unmapped drive). 
+        /// </exception>
+        /// <exception cref="PathTooLongException">
+        ///     The specified <paramref name="path"/>, file name, or both exceed the system-defined maximum length. 
+        ///     For example, on Windows-based platforms, paths must be less than 248 characters and file names must 
+        ///     be less than 260 characters. 
+        /// </exception>
+        /// <exception cref="UnauthorizedAccessException">
+        ///     The caller does not have the required permission. 
+        /// </exception>
+        public DirectoryCatalog(string path, string searchPattern)
+        {
+            Requires.NotNullOrEmpty(path, "path");
+            Requires.NotNullOrEmpty(searchPattern, "searchPattern");
+
+            this._definitionOrigin = this;
+            this.Initialize(path, searchPattern);
+        }
+
+        /// <summary>
+        ///     Creates a catalog of <see cref="ComposablePartDefinition"/>s based on all the *.dll files 
+        ///     in the given directory path.
+        ///
+        ///     Possible exceptions that can be thrown are any that <see cref="Directory.GetFiles(string, string)"/> or 
+        ///     <see cref="Assembly.Load(AssemblyName)"/> can throw.
+        /// </summary>
+        /// <param name="path">
+        ///     Path to the directory to scan for assemblies to add to the catalog.
+        ///     The path needs to be absolute or relative to <see cref="AppDomain.BaseDirectory"/>
+        /// </param>
+        /// <param name="definitionOrigin">
+        ///     The <see cref="ICompositionElement"/> CompositionElement used by Diagnostics to identify the source for parts.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     If <paramref name="path"/> is a zero-length string, contains only white space, or 
+        ///     contains one or more implementation-specific invalid characters. Or <paramref name="searchPattern"/> 
+        ///     does not contain a valid pattern. 
+        /// </exception>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="path"/> is <see langword="null"/>.
+        ///     <paramref name="definitionOrigin"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="DirectoryNotFoundException">
+        ///     The specified <paramref name="path"/> is invalid (for example, it is on an unmapped drive). 
+        /// </exception>
+        /// <exception cref="PathTooLongException">
+        ///     The specified <paramref name="path"/>, file name, or both exceed the system-defined maximum length. 
+        ///     For example, on Windows-based platforms, paths must be less than 248 characters and file names must 
+        ///     be less than 260 characters. 
+        /// </exception>
+        /// <exception cref="UnauthorizedAccessException">
+        ///     The caller does not have the required permission. 
+        /// </exception>
+        public DirectoryCatalog(string path, string searchPattern, ICompositionElement definitionOrigin)
+        {
+            Requires.NotNullOrEmpty(path, "path");
+            Requires.NotNullOrEmpty(searchPattern, "searchPattern");
+            Requires.NotNull(definitionOrigin, "definitionOrigin");
+
+            this._definitionOrigin = definitionOrigin;
+            this.Initialize(path, searchPattern);
+        }
+
+#if FEATURE_REFLECTIONCONTEXT
+        /// <summary>
+        ///     Creates a catalog of <see cref="ComposablePartDefinition"/>s based on all the given searchPattern 
+        ///     over the files in the given directory path.
+        ///     
+        ///     Possible exceptions that can be thrown are any that <see cref="Directory.GetFiles(string, string)"/> or 
+        ///     <see cref="Assembly.Load(AssemblyName)"/> can throw.
+        /// </summary>
+        /// <param name="path">
+        ///     Path to the directory to scan for assemblies to add to the catalog.
+        ///     The path needs to be absolute or relative to <see cref="AppDomain.BaseDirectory"/>
+        /// </param>
+        /// <param name="searchPattern">
+        ///     Any valid searchPattern that <see cref="Directory.GetFiles(string, string)"/> will accept.
+        /// </param>
+        /// <param name="reflectionContext">
+        ///     The <see cref="ReflectionContext"/> a context used by the catalog when 
+        ///     interpreting the types to inject attributes into the type definition.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     If <paramref name="path"/> is a zero-length string, contains only white space, or 
+        ///     contains one or more implementation-specific invalid characters. Or <paramref name="searchPattern"/> 
+        ///     does not contain a valid pattern. 
+        /// </exception>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="path"/> is <see langword="null"/> 
+        ///     or <paramref name="searchPattern"/> is <see langword="null"/>.
+        ///     or <paramref name="reflectionContext"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="DirectoryNotFoundException">
+        ///     The specified <paramref name="path"/> is invalid (for example, it is on an unmapped drive). 
+        /// </exception>
+        /// <exception cref="PathTooLongException">
+        ///     The specified <paramref name="path"/>, file name, or both exceed the system-defined maximum length. 
+        ///     For example, on Windows-based platforms, paths must be less than 248 characters and file names must 
+        ///     be less than 260 characters. 
+        /// </exception>
+        /// <exception cref="UnauthorizedAccessException">
+        ///     The caller does not have the required permission. 
+        /// </exception>
+        public DirectoryCatalog(string path, string searchPattern, ReflectionContext reflectionContext)
+        {
+            Requires.NotNullOrEmpty(path, "path");
+            Requires.NotNullOrEmpty(searchPattern, "searchPattern");
+            Requires.NotNull(reflectionContext, "reflectionContext");
+
+            this._reflectionContext = reflectionContext;
+            this._definitionOrigin = this;
+            this.Initialize(path, searchPattern);
+        }
+
+        /// <summary>
+        ///     Creates a catalog of <see cref="ComposablePartDefinition"/>s based on all the given searchPattern 
+        ///     over the files in the given directory path.
+        ///     
+        ///     Possible exceptions that can be thrown are any that <see cref="Directory.GetFiles(string, string)"/> or 
+        ///     <see cref="Assembly.Load(AssemblyName)"/> can throw.
+        /// </summary>
+        /// <param name="path">
+        ///     Path to the directory to scan for assemblies to add to the catalog.
+        ///     The path needs to be absolute or relative to <see cref="AppDomain.BaseDirectory"/>
+        /// </param>
+        /// <param name="searchPattern">
+        ///     Any valid searchPattern that <see cref="Directory.GetFiles(string, string)"/> will accept.
+        /// </param>
+        /// <param name="reflectionContext">
+        ///     The <see cref="ReflectionContext"/> a context used by the catalog when 
+        ///     interpreting the types to inject attributes into the type definition.
+        /// </param>
+        /// <param name="definitionOrigin">
+        ///     The <see cref="ICompositionElement"/> CompositionElement used by Diagnostics to identify the source for parts.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     If <paramref name="path"/> is a zero-length string, contains only white space, or 
+        ///     contains one or more implementation-specific invalid characters. Or <paramref name="searchPattern"/> 
+        ///     does not contain a valid pattern. 
+        /// </exception>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="path"/> is <see langword="null"/> 
+        ///     or <paramref name="searchPattern"/> is <see langword="null"/>.
+        ///     or <paramref name="reflectionContext"/> is <see langword="null"/>.
+        ///     or <paramref name="definitionOrigin"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="DirectoryNotFoundException">
+        ///     The specified <paramref name="path"/> is invalid (for example, it is on an unmapped drive). 
+        /// </exception>
+        /// <exception cref="PathTooLongException">
+        ///     The specified <paramref name="path"/>, file name, or both exceed the system-defined maximum length. 
+        ///     For example, on Windows-based platforms, paths must be less than 248 characters and file names must 
+        ///     be less than 260 characters. 
+        /// </exception>
+        /// <exception cref="UnauthorizedAccessException">
+        ///     The caller does not have the required permission. 
+        /// </exception>
+        public DirectoryCatalog(string path, string searchPattern, ReflectionContext reflectionContext, ICompositionElement definitionOrigin)
+        {
+            Requires.NotNullOrEmpty(path, "path");
+            Requires.NotNullOrEmpty(searchPattern, "searchPattern");
+            Requires.NotNull(reflectionContext, "reflectionContext");
+            Requires.NotNull(definitionOrigin, "definitionOrigin");
+
+            this._reflectionContext = reflectionContext;
+            this._definitionOrigin = definitionOrigin;
+            this.Initialize(path, searchPattern);
+        }
+#endif //FEATURE_REFLECTIONCONTEXT
+
+        /// <summary>
+        ///     Translated absolute path of the path passed into the constructor of <see cref="DirectoryCatalog"/>. 
+        /// </summary>
+        public string FullPath
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<string>() != null);
+                
+                return this._fullPath;
+            }
+        }
+
+        /// <summary>
+        ///     Set of files that have currently been loaded into the catalog.
+        /// </summary>
+        public ReadOnlyCollection<string> LoadedFiles
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<ReadOnlyCollection<string>>() != null);
+
+                using (new ReadLock(this._thisLock))
+                {
+                    return this._loadedFiles;
+                }
+            }
+        }
+
+        /// <summary>
+        ///     Path passed into the constructor of <see cref="DirectoryCatalog"/>.
+        /// </summary>
+        public string Path
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<string>() != null);
+                
+                return this._path;
+            }
+        }
+
+        /// <summary>
+        ///   SearchPattern passed into the constructor of <see cref="DirectoryCatalog"/>, or the default *.dll.
+        /// </summary>
+        public string SearchPattern
+        {
+            get
+            {
+                return this._searchPattern;
+            }
+        }
+
+        /// <summary>
+        /// Notify when the contents of the Catalog has changed.
+        /// </summary>
+        public event EventHandler<ComposablePartCatalogChangeEventArgs> Changed;
+
+        /// <summary>
+        /// Notify when the contents of the Catalog has changing.
+        /// </summary>
+        public event EventHandler<ComposablePartCatalogChangeEventArgs> Changing;
+
+        /// <summary>
+        /// Releases unmanaged and - optionally - managed resources
+        /// </summary>
+        /// <param name="disposing"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
+        protected override void Dispose(bool disposing)
+        {
+            try
+            {
+                if (disposing)
+                {
+                    if (!this._isDisposed)
+                    {
+                        bool disposeLock = false;
+                        ComposablePartCatalogCollection catalogs = null;
+
+                        try
+                        {
+                            using (new WriteLock(this._thisLock))
+                            {
+                                if (!this._isDisposed)
+                                {
+                                    disposeLock = true;
+                                    catalogs = this._catalogCollection;
+                                    this._catalogCollection = null;
+                                    this._assemblyCatalogs = null;
+                                    this._isDisposed = true;
+                                }
+                            }
+                        }
+                        finally
+                        {
+                            if (catalogs != null)
+                            {
+                                catalogs.Dispose();
+                            }
+
+                            if (disposeLock)
+                            {
+                                this._thisLock.Dispose();
+                            }
+                        }
+                    }
+                }
+            }
+            finally
+            {
+                base.Dispose(disposing);
+            }
+        }
+
+        public override IEnumerator<ComposablePartDefinition> GetEnumerator()
+        {
+            return this._catalogCollection.SelectMany(catalog => catalog as IEnumerable<ComposablePartDefinition>).GetEnumerator();
+        }
+
+        /// <summary>
+        ///     Returns the export definitions that match the constraint defined by the specified definition.
+        /// </summary>
+        /// <param name="definition">
+        ///     The <see cref="ImportDefinition"/> that defines the conditions of the 
+        ///     <see cref="ExportDefinition"/> objects to return.
+        /// </param>
+        /// <returns>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="Tuple{T1, T2}"/> containing the 
+        ///     <see cref="ExportDefinition"/> objects and their associated 
+        ///     <see cref="ComposablePartDefinition"/> for objects that match the constraint defined 
+        ///     by <paramref name="definition"/>.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="definition"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="DirectoryCatalog"/> has been disposed of.
+        /// </exception>
+        public override IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>> GetExports(ImportDefinition definition)
+        {
+            this.ThrowIfDisposed();
+
+            Requires.NotNull(definition, "definition");
+
+            return this._catalogCollection.SelectMany(catalog => catalog.GetExports(definition));
+        }
+
+        /// <summary>
+        ///     Raises the <see cref="INotifyComposablePartCatalogChanged.Changed"/> event.
+        /// </summary>
+        /// <param name="e">
+        ///     An <see cref="ComposablePartCatalogChangeEventArgs"/> containing the data for the event.
+        /// </param>
+        protected virtual void OnChanged(ComposablePartCatalogChangeEventArgs e)
+        {
+            EventHandler<ComposablePartCatalogChangeEventArgs> changedEvent = this.Changed;
+            if (changedEvent != null)
+            {
+                changedEvent(this, e);
+            }
+        }
+
+        /// <summary>
+        ///     Raises the <see cref="INotifyComposablePartCatalogChanged.Changing"/> event.
+        /// </summary>
+        /// <param name="e">
+        ///     An <see cref="ComposablePartCatalogChangeEventArgs"/> containing the data for the event.
+        /// </param>
+        protected virtual void OnChanging(ComposablePartCatalogChangeEventArgs e)
+        {
+            EventHandler<ComposablePartCatalogChangeEventArgs> changingEvent = this.Changing;
+            if (changingEvent != null)
+            {
+                changingEvent(this, e);
+            }
+        }
+
+        /// <summary>
+        ///     Refreshes the <see cref="ComposablePartDefinition"/>s with the latest files in the directory that match
+        ///     the searchPattern. If any files have been added they will be added to the catalog and if any files were
+        ///     removed they will be removed from the catalog. For files that have been removed keep in mind that the 
+        ///     assembly cannot be unloaded from the process so <see cref="ComposablePartDefinition"/>s for those files
+        ///     will simply be removed from the catalog.
+        /// 
+        ///     Possible exceptions that can be thrown are any that <see cref="Directory.GetFiles(string, string)"/> or 
+        ///     <see cref="Assembly.Load(AssemblyName)"/> can throw.
+        /// </summary>
+        /// <exception cref="DirectoryNotFoundException">
+        ///     The specified path has been removed since object construction.
+        /// </exception>
+        public void Refresh()
+        {
+            this.ThrowIfDisposed();
+            Assumes.NotNull(this._loadedFiles);
+
+            List<Tuple<string, AssemblyCatalog>> catalogsToAdd;
+            List<Tuple<string, AssemblyCatalog>> catalogsToRemove;
+            ComposablePartDefinition[] addedDefinitions;
+            ComposablePartDefinition[] removedDefinitions;
+            object changeReferenceObject;
+            string[] afterFiles;
+            string[] beforeFiles;
+
+            while (true)
+            {
+                afterFiles = this.GetFiles();
+
+                using (new ReadLock(this._thisLock))
+                {
+                    changeReferenceObject = this._loadedFiles;
+                    beforeFiles = this._loadedFiles.ToArray();
+                }
+
+                this.DiffChanges(beforeFiles, afterFiles, out catalogsToAdd, out catalogsToRemove);
+
+                // Don't go any further if there's no work to do
+                if (catalogsToAdd.Count == 0 && catalogsToRemove.Count == 0)
+                {
+                    return;
+                }
+
+                // Notify listeners to give them a preview before completeting the changes
+                addedDefinitions = catalogsToAdd
+                    .SelectMany(cat => cat.Item2 as IEnumerable<ComposablePartDefinition>)
+                    .ToArray<ComposablePartDefinition>();
+
+                removedDefinitions = catalogsToRemove
+                    .SelectMany(cat => cat.Item2 as IEnumerable<ComposablePartDefinition>)
+                    .ToArray<ComposablePartDefinition>();
+
+                using (var atomicComposition = new AtomicComposition())
+                {
+                    var changingArgs = new ComposablePartCatalogChangeEventArgs(addedDefinitions, removedDefinitions, atomicComposition);
+                    this.OnChanging(changingArgs);
+
+                    // if the change went through then write the catalog changes
+                    using (new WriteLock(this._thisLock))
+                    {
+                        if (changeReferenceObject != this._loadedFiles)
+                        {
+                            // Someone updated the list while we were diffing so we need to try the diff again
+                            continue;
+                        }
+
+                        foreach (var catalogToAdd in catalogsToAdd)
+                        {
+                            this._assemblyCatalogs.Add(catalogToAdd.Item1, catalogToAdd.Item2);
+                            this._catalogCollection.Add(catalogToAdd.Item2);
+                        }
+
+                        foreach (var catalogToRemove in catalogsToRemove)
+                        {
+                            this._assemblyCatalogs.Remove(catalogToRemove.Item1);
+                            this._catalogCollection.Remove(catalogToRemove.Item2);
+                        }
+
+                        this._loadedFiles = afterFiles.ToReadOnlyCollection();
+
+                        // Lastly complete any changes added to the atomicComposition during the change event
+                        atomicComposition.Complete();
+
+                        // Break out of the while(true)
+                        break;
+                    } // WriteLock
+                } // AtomicComposition
+            }   // while (true)
+
+            var changedArgs = new ComposablePartCatalogChangeEventArgs(addedDefinitions, removedDefinitions, null);
+            this.OnChanged(changedArgs);
+        }
+
+        /// <summary>
+        ///     Returns a string representation of the directory catalog.
+        /// </summary>
+        /// <returns>
+        ///     A <see cref="String"/> containing the string representation of the <see cref="DirectoryCatalog"/>.
+        /// </returns>
+        public override string ToString()
+        {
+            return GetDisplayName();
+        }
+
+        private AssemblyCatalog CreateAssemblyCatalogGuarded(string assemblyFilePath)
+        {
+            Exception exception = null;
+
+            try
+            {
+#if FEATURE_REFLECTIONCONTEXT
+                return (this._reflectionContext != null)
+                    ? new AssemblyCatalog(assemblyFilePath, this._reflectionContext, this)
+                    : new AssemblyCatalog(assemblyFilePath, this);
+#else
+                return new AssemblyCatalog(assemblyFilePath, this);
+#endif //FEATURE_REFLECTIONCONTEXT
+            }
+            catch (FileNotFoundException ex)
+            {   // Files should always exists but don't blow up here if they don't
+                exception = ex;
+            }
+            catch (FileLoadException ex)
+            {   // File was found but could not be loaded
+                exception = ex;
+            }
+            catch (BadImageFormatException ex)
+            {   // Dlls that contain native code are not loaded, but do not invalidate the Directory
+                exception = ex;
+            }
+            catch (ReflectionTypeLoadException ex)
+            {   // Dlls that have missing Managed dependencies are not loaded, but do not invalidate the Directory 
+                exception = ex;
+            }
+
+            CompositionTrace.AssemblyLoadFailed(this, assemblyFilePath, exception);
+
+            return null;
+        }
+
+        private void DiffChanges(string[] beforeFiles, string[] afterFiles,
+            out List<Tuple<string, AssemblyCatalog>> catalogsToAdd,
+            out List<Tuple<string, AssemblyCatalog>> catalogsToRemove)
+        {
+            catalogsToAdd = new List<Tuple<string, AssemblyCatalog>>();
+            catalogsToRemove = new List<Tuple<string, AssemblyCatalog>>();
+
+            IEnumerable<string> filesToAdd = afterFiles.Except(beforeFiles);
+            foreach (string file in filesToAdd)
+            {
+                AssemblyCatalog catalog = CreateAssemblyCatalogGuarded(file);
+
+                if (catalog != null)
+                {
+                    catalogsToAdd.Add(new Tuple<string, AssemblyCatalog>(file, catalog));
+                }
+            }
+
+            IEnumerable<string> filesToRemove = beforeFiles.Except(afterFiles);
+            using (new ReadLock(this._thisLock))
+            {
+                foreach (string file in filesToRemove)
+                {
+                    AssemblyCatalog catalog;
+                    if (this._assemblyCatalogs.TryGetValue(file, out catalog))
+                    {
+                        catalogsToRemove.Add(new Tuple<string, AssemblyCatalog>(file, catalog));
+                    }
+                }
+            }
+        }
+
+        private string GetDisplayName()
+        {
+            return string.Format(CultureInfo.CurrentCulture,
+                                "{0} (Path=\"{1}\")",   // NOLOC
+                                this.GetType().Name,
+                                this._path);
+        }
+
+        private string[] GetFiles()
+        {
+            string[] files = Directory.GetFiles(this._fullPath, this._searchPattern);
+            return Array.ConvertAll<string, string>(files, (file) => file.ToUpperInvariant());
+        }
+
+        private static string GetFullPath(string path)
+        {
+            if (!IOPath.IsPathRooted(path) && AppDomain.CurrentDomain.BaseDirectory != null)
+            {
+                path = IOPath.Combine(AppDomain.CurrentDomain.BaseDirectory, path);
+            }
+
+            return IOPath.GetFullPath(path).ToUpperInvariant();
+        }
+
+        private void Initialize(string path, string searchPattern)
+        {
+            this._path = path;
+            this._fullPath = GetFullPath(path);
+            this._searchPattern = searchPattern;
+            this._assemblyCatalogs = new Dictionary<string, AssemblyCatalog>();
+            this._catalogCollection = new ComposablePartCatalogCollection(null, null, null);
+
+            this._loadedFiles = GetFiles().ToReadOnlyCollection();
+
+            foreach (string file in this._loadedFiles)
+            {
+                AssemblyCatalog assemblyCatalog = null;
+                assemblyCatalog = CreateAssemblyCatalogGuarded(file);
+
+                if (assemblyCatalog != null)
+                {
+                    this._assemblyCatalogs.Add(file, assemblyCatalog);
+                    this._catalogCollection.Add(assemblyCatalog);
+                }
+            }
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+       
+        /// <summary>
+        ///     Gets the display name of the directory catalog.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="String"/> containing a human-readable display name of the <see cref="DirectoryCatalog"/>.
+        /// </value>
+        [SuppressMessage("Microsoft.Design", "CA1033:InterfaceMethodsShouldBeCallableByChildTypes")]
+        string ICompositionElement.DisplayName
+        {
+            get { return this.GetDisplayName(); }
+        }
+
+        /// <summary>
+        ///     Gets the composition element from which the directory catalog originated.
+        /// </summary>
+        /// <value>
+        ///     This property always returns <see langword="null"/>.
+        /// </value>
+        [SuppressMessage("Microsoft.Design", "CA1033:InterfaceMethodsShouldBeCallableByChildTypes")]
+        ICompositionElement ICompositionElement.Origin
+        {
+            get { return null; }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ExportProvider.GetExportOverrides.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ExportProvider.GetExportOverrides.cs
new file mode 100644
index 00000000000..3915089fd34
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ExportProvider.GetExportOverrides.cs
@@ -0,0 +1,819 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Collections.ObjectModel;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using System.ComponentModel.Composition.ReflectionModel;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public abstract partial class ExportProvider
+    {
+        /// <summary>
+        ///     Returns the export with the contract name derived from the specified type parameter, 
+        ///     throwing an exception if there is not exactly one matching export.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the <see cref="Lazy{T}"/> object to return. The contract name is also 
+        ///     derived from this type parameter.
+        /// </typeparam>
+        /// <returns>
+        ///     The <see cref="Lazy{T}"/> object with the contract name derived from 
+        ///     <typeparamref name="T"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         The returned <see cref="Lazy{T}"/> object is an instance of 
+        ///         <see cref="Lazy{T, TMetadataView}"/> underneath, where 
+        ///         <c>TMetadataView</c>
+        ///         is <see cref="IDictionary{TKey, TValue}"/> and where <c>TKey</c> 
+        ///         is <see cref="String"/> and <c>TValue</c> is <see cref="Object"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="ImportCardinalityMismatchException">
+        ///     <para>
+        ///         There are zero <see cref="Lazy{T}"/> objects with the contract name derived 
+        ///         from <typeparamref name="T"/> in the <see cref="CompositionContainer"/>.
+        ///     </para>
+        ///     -or-
+        ///     <para>
+        ///         There are more than one <see cref="Lazy{T}"/> objects with the contract name 
+        ///         derived from <typeparamref name="T"/> in the <see cref="CompositionContainer"/>.
+        ///     </para>
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        public Lazy<T> GetExport<T>()
+        {
+            return this.GetExport<T>((string)null);
+        }
+
+        /// <summary>
+        ///     Returns the export with the specified contract name, throwing an exception if there 
+        ///     is not exactly one matching export.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the <see cref="Lazy{T}"/> object to return.
+        /// </typeparam>
+        /// <param name="contractName">
+        ///     A <see cref="String"/> containing the contract name of the <see cref="Lazy{T}"/> 
+        ///     object to return; or <see langword="null"/> or an empty string ("") to use the 
+        ///     default contract name.
+        /// </param>
+        /// <returns>
+        ///     The <see cref="Lazy{T}"/> object with the specified contract name.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         The returned <see cref="Lazy{T}"/> object is an instance of 
+        ///         <see cref="Lazy{T, TMetadataView}"/> underneath, where 
+        ///         <c>TMetadataView</c>
+        ///         is <see cref="IDictionary{TKey, TValue}"/> and where <c>TKey</c> 
+        ///         is <see cref="String"/> and <c>TValue</c> is <see cref="Object"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The default contract name is compared using a case-sensitive, non-linguistic 
+        ///         comparison using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="ImportCardinalityMismatchException">
+        ///     <para>
+        ///         There are zero <see cref="Lazy{T}"/> objects with the specified contract name 
+        ///         in the <see cref="CompositionContainer"/>.
+        ///     </para>
+        ///     -or-
+        ///     <para>
+        ///         There are more than one <see cref="Lazy{T}"/> objects with the specified contract
+        ///         name in the <see cref="CompositionContainer"/>.
+        ///     </para>
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        public Lazy<T> GetExport<T>(string contractName)
+        {
+            return this.GetExportCore<T>(contractName);
+        }
+
+        /// <summary>
+        ///     Returns the export with the contract name derived from the specified type parameter, 
+        ///     throwing an exception if there is not exactly one matching export.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the <see cref="Lazy{T, TMetadataView}"/> object to return. The 
+        ///     contract name is also derived from this type parameter.
+        /// </typeparam>
+        /// <typeparam name="TMetadataView">
+        ///     The type of the metadata view of the <see cref="Lazy{T, TMetadataView}"/> object
+        ///     to return.
+        /// </typeparam>
+        /// <returns>
+        ///     The <see cref="Lazy{T, TMetadataView}"/> object with the contract name derived 
+        ///     from <typeparamref name="T"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         The contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="ImportCardinalityMismatchException">
+        ///     <para>
+        ///         There are zero <see cref="Lazy{T, TMetadataView}"/> objects with the contract 
+        ///         name derived from <typeparamref name="T"/> in the 
+        ///         <see cref="CompositionContainer"/>.
+        ///     </para>
+        ///     -or-
+        ///     <para>
+        ///         There are more than one <see cref="Lazy{T, TMetadataView}"/> objects with the 
+        ///         contract name derived from <typeparamref name="T"/> in the 
+        ///         <see cref="CompositionContainer"/>.
+        ///     </para>
+        /// </exception>
+        /// <exception cref="InvalidOperationException">
+        ///     <typeparamref name="TMetadataView"/> is not a valid metadata view type.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        public Lazy<T, TMetadataView> GetExport<T, TMetadataView>()
+        {
+            return this.GetExport<T, TMetadataView>((string)null);
+        }
+
+        /// <summary>
+        ///     Returns the export with the specified contract name, throwing an exception if there 
+        ///     is not exactly one matching export.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the <see cref="Lazy{T, TMetadataView}"/> object to return.
+        /// </typeparam>
+        /// <typeparam name="TMetadataView">
+        ///     The type of the metadata view of the <see cref="Lazy{T, TMetadataView}"/> object
+        ///     to return.
+        /// </typeparam>
+        /// <param name="contractName">
+        ///     A <see cref="String"/> containing the contract name of the 
+        ///     <see cref="Lazy{T, TMetadataView}"/> object to return; or <see langword="null"/> 
+        ///     or an empty string ("") to use the default contract name.
+        /// </param>
+        /// <returns>
+        ///     The <see cref="Lazy{T, TMetadataView}"/> object with the specified contract name.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="ImportCardinalityMismatchException">
+        ///     <para>
+        ///         There are zero <see cref="Lazy{T, TMetadataView}"/> objects with the 
+        ///         specified contract name in the <see cref="CompositionContainer"/>.
+        ///     </para>
+        ///     -or-
+        ///     <para>
+        ///         There are more than one <see cref="Lazy{T, TMetadataView}"/> objects with the 
+        ///         specified contract name in the <see cref="CompositionContainer"/>.
+        ///     </para>
+        /// </exception>
+        /// <exception cref="InvalidOperationException">
+        ///     <typeparamref name="TMetadataView"/> is not a valid metadata view type.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        public Lazy<T, TMetadataView> GetExport<T, TMetadataView>(string contractName)
+        {
+            return this.GetExportCore<T, TMetadataView>(contractName);
+        }
+
+        /// <summary>
+        ///     Returns the exports with the specified contract name.
+        /// </summary>
+        /// <param name="type">
+        ///     The <see cref="Type"/> of the <see cref="Export"/> objects to return.
+        /// </param>
+        /// <param name="metadataViewType">
+        ///     The <see cref="Type"/> of the metadata view of the <see cref="Export"/> objects to
+        ///     return.
+        /// </param>
+        /// <param name="contractName">
+        ///     A <see cref="String"/> containing the contract name of the 
+        ///     <see cref="Export"/> object to return; or <see langword="null"/> 
+        ///     or an empty string ("") to use the default contract name.
+        /// </param>
+        /// <returns>
+        ///     An <see cref="IEnumerable{T}"/> containing the <see cref="Lazy{Object, Object}"/> objects 
+        ///     with the specified contract name, if found; otherwise, an empty 
+        ///     <see cref="IEnumerable{T}"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         The returned <see cref="Export"/> objects are instances of 
+        ///         <see cref="Lazy{T, TMetadataView}"/> underneath, where <c>T</c>
+        ///         is <paramref name="type"/> and <c>TMetadataView</c> is 
+        ///         <paramref name="metadataViewType"/>.
+        ///     </para>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <paramref name="type"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="type"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="InvalidOperationException">
+        ///     <paramref name="metadataViewType"/> is not a valid metadata view type.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        [SuppressMessage("Microsoft.Design", "CA1006")]
+        public IEnumerable<Lazy<object, object>> GetExports(Type type, Type metadataViewType, string contractName)
+        {
+            IEnumerable<Export> exports = this.GetExportsCore(type, metadataViewType, contractName, ImportCardinality.ZeroOrMore);
+            Collection<Lazy<object, object>> result = new Collection<Lazy<object, object>>();
+
+            Func<Export, Lazy<object, object>> typedExportFactory = ExportServices.CreateSemiStronglyTypedLazyFactory(type, metadataViewType);
+            foreach (Export export in exports)
+            {
+                result.Add(typedExportFactory.Invoke(export));
+            }
+
+            return result;
+        }
+
+        /// <summary>
+        ///     Returns the exports with the contract name derived from the specified type parameter.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the <see cref="Lazy{T}"/> objects to return. The contract name is also 
+        ///     derived from this type parameter.
+        /// </typeparam>
+        /// <returns>
+        ///     An <see cref="IEnumerable{T}"/> containing the <see cref="Lazy{T}"/> objects
+        ///     with the contract name derived from <typeparamref name="T"/>, if found; otherwise,
+        ///     an empty <see cref="IEnumerable{T}"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         The returned <see cref="Lazy{T}"/> objects are instances of 
+        ///         <see cref="Lazy{T, TMetadataView}"/> underneath, where 
+        ///         <c>TMetadataView</c>
+        ///         is <see cref="IDictionary{TKey, TValue}"/> and where <c>TKey</c> 
+        ///         is <see cref="String"/> and <c>TValue</c> is <see cref="Object"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        [SuppressMessage("Microsoft.Design", "CA1006")]
+        public IEnumerable<Lazy<T>> GetExports<T>()
+        {
+            return this.GetExports<T>((string)null);
+        }
+
+        /// <summary>
+        ///     Returns the exports with the specified contract name.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the <see cref="Lazy{T}"/> objects to return.
+        /// </typeparam>
+        /// <param name="contractName">
+        ///     A <see cref="String"/> containing the contract name of the <see cref="Lazy{T}"/> 
+        ///     objects to return; or <see langword="null"/> or an empty string ("") to use the 
+        ///     default contract name.
+        /// </param>
+        /// <returns>
+        ///     An <see cref="IEnumerable{T}"/> containing the <see cref="Lazy{T}"/> objects
+        ///     with the specified contract name, if found; otherwise, an empty 
+        ///     <see cref="IEnumerable{T}"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         The returned <see cref="Lazy{T}"/> objects are instances of 
+        ///         <see cref="Lazy{T, TMetadataView}"/> underneath, where 
+        ///         <c>TMetadataView</c>
+        ///         is <see cref="IDictionary{TKey, TValue}"/> and where <c>TKey</c> 
+        ///         is <see cref="String"/> and <c>TValue</c> is <see cref="Object"/>.
+        ///     </para>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        [SuppressMessage("Microsoft.Design", "CA1006")]
+        public IEnumerable<Lazy<T>> GetExports<T>(string contractName)
+        {
+            return this.GetExportsCore<T>(contractName);
+        }
+
+        /// <summary>
+        ///     Returns the exports with the contract name derived from the specified type parameter.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the <see cref="Lazy{T, TMetadataView}"/> objects to return. The 
+        ///     contract name is also derived from this type parameter.
+        /// </typeparam>
+        /// <typeparam name="TMetadataView">
+        ///     The type of the metadata view of the <see cref="Lazy{T, TMetadataView}"/> objects
+        ///     to return.
+        /// </typeparam>
+        /// <returns>
+        ///     An <see cref="IEnumerable{T}"/> containing the 
+        ///     <see cref="Lazy{T, TMetadataView}"/> objects with the contract name derived from 
+        ///     <typeparamref name="T"/>, if found; otherwise, an empty 
+        ///     <see cref="IEnumerable{T}"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         The contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="InvalidOperationException">
+        ///     <typeparamref name="TMetadataView"/> is not a valid metadata view type.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        [SuppressMessage("Microsoft.Design", "CA1006")]
+        public IEnumerable<Lazy<T, TMetadataView>> GetExports<T, TMetadataView>()
+        {
+            return this.GetExports<T, TMetadataView>((string)null);
+        }
+
+        /// <summary>
+        ///     Returns the exports with the specified contract name.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the <see cref="Lazy{T, TMetadataView}"/> objects to return. The 
+        ///     contract name is also derived from this type parameter.
+        /// </typeparam>
+        /// <typeparam name="TMetadataView">
+        ///     The type of the metadata view of the <see cref="Lazy{T, TMetadataView}"/> objects
+        ///     to return.
+        /// </typeparam>
+        /// <param name="contractName">
+        ///     A <see cref="String"/> containing the contract name of the 
+        ///     <see cref="Lazy{T, TMetadataView}"/> objects to return; or <see langword="null"/> 
+        ///     or an empty string ("") to use the default contract name.
+        /// </param>
+        /// <returns>
+        ///     An <see cref="IEnumerable{T}"/> containing the 
+        ///     <see cref="Lazy{T, TMetadataView}"/> objects with the specified contract name if 
+        ///     found; otherwise, an empty <see cref="IEnumerable{T}"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="InvalidOperationException">
+        ///     <typeparamref name="TMetadataView"/> is not a valid metadata view type.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        [SuppressMessage("Microsoft.Design", "CA1006")]
+        public IEnumerable<Lazy<T, TMetadataView>> GetExports<T, TMetadataView>(string contractName)
+        {
+            return this.GetExportsCore<T, TMetadataView>(contractName);
+        }
+
+        /// <summary>
+        ///     Returns the exported value with the contract name derived from the specified type 
+        ///     parameter, throwing an exception if there is not exactly one matching exported value.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the exported value to return. The contract name is also 
+        ///     derived from this type parameter.
+        /// </typeparam>
+        /// <returns>
+        ///     The exported <see cref="Object"/> with the contract name derived from 
+        ///     <typeparamref name="T"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         The contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="CompositionContractMismatchException">
+        ///     The underlying exported value cannot be cast to <typeparamref name="T"/>.
+        /// </exception>
+        /// <exception cref="ImportCardinalityMismatchException">
+        ///     <para>
+        ///         There are zero exported values with the contract name derived from 
+        ///         <typeparamref name="T"/> in the <see cref="CompositionContainer"/>.
+        ///     </para>
+        ///     -or-
+        ///     <para>
+        ///         There are more than one exported values with the contract name derived from
+        ///         <typeparamref name="T"/> in the <see cref="CompositionContainer"/>.
+        ///     </para>
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will 
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        public T GetExportedValue<T>()
+        {
+            return this.GetExportedValue<T>((string)null);
+        }
+
+        /// <summary>
+        ///     Returns the exported value with the specified contract name, throwing an exception 
+        ///     if there is not exactly one matching exported value.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the exported value to return.
+        /// </typeparam>
+        /// <param name="contractName">
+        ///     A <see cref="String"/> containing the contract name of the exported value to return,
+        ///     or <see langword="null"/> or an empty string ("") to use the default contract name.
+        /// </param>
+        /// <returns>
+        ///     The exported <see cref="Object"/> with the specified contract name.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="CompositionContractMismatchException">
+        ///     The underlying exported value cannot be cast to <typeparamref name="T"/>.
+        /// </exception>
+        /// <exception cref="ImportCardinalityMismatchException">
+        ///     <para>
+        ///         There are zero exported values with the specified contract name in the 
+        ///         <see cref="CompositionContainer"/>.
+        ///     </para>
+        ///     -or-
+        ///     <para>
+        ///         There are more than one exported values with the specified contract name in the
+        ///         <see cref="CompositionContainer"/>.
+        ///     </para>
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will 
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        public T GetExportedValue<T>(string contractName)
+        {
+            return this.GetExportedValueCore<T>(contractName, ImportCardinality.ExactlyOne);
+        }
+
+        /// <summary>
+        ///     Returns the exported value with the contract name derived from the specified type 
+        ///     parameter, throwing an exception if there is more than one matching exported value.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the exported value to return. The contract name is also 
+        ///     derived from this type parameter.
+        /// </typeparam>
+        /// <returns>
+        ///     The exported <see cref="Object"/> with the contract name derived from 
+        ///     <typeparamref name="T"/>, if found; otherwise, the default value for
+        ///     <typeparamref name="T"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         If the exported value is not found, then this method returns the appropriate 
+        ///         default value for <typeparamref name="T"/>; for example, 0 (zero) for integer 
+        ///         types, <see langword="false"/> for Boolean types, and <see langword="null"/> 
+        ///         for reference types.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="CompositionContractMismatchException">
+        ///     The underlying exported value cannot be cast to <typeparamref name="T"/>.
+        /// </exception>
+        /// <exception cref="ImportCardinalityMismatchException">
+        ///     <para>
+        ///         There are more than one exported values with the contract name derived from
+        ///         <typeparamref name="T"/> in the <see cref="CompositionContainer"/>.
+        ///     </para>
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will 
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        public T GetExportedValueOrDefault<T>()
+        {
+            return this.GetExportedValueOrDefault<T>((string)null);
+        }
+
+        /// <summary>
+        ///     Returns the exported value with the specified contract name, throwing an exception 
+        ///     if there is more than one matching exported value.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the exported value to return.
+        /// </typeparam>
+        /// <param name="contractName">
+        ///     A <see cref="String"/> containing the contract name of the exported value to return,
+        ///     or <see langword="null"/> or an empty string ("") to use the default contract name.
+        /// </param>
+        /// <returns>
+        ///     The exported <see cref="Object"/> with the specified contract name, if found; 
+        ///     otherwise, the default value for <typeparamref name="T"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         If the exported value is not found, then this method returns the appropriate 
+        ///         default value for <typeparamref name="T"/>; for example, 0 (zero) for integer 
+        ///         types, <see langword="false"/> for Boolean types, and <see langword="null"/> 
+        ///         for reference types.
+        ///     </para>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="CompositionContractMismatchException">
+        ///     The underlying exported value cannot be cast to <typeparamref name="T"/>.
+        /// </exception>
+        /// <exception cref="ImportCardinalityMismatchException">
+        ///     There are more than one exported values with the specified contract name in the
+        ///     <see cref="CompositionContainer"/>.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will 
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        public T GetExportedValueOrDefault<T>(string contractName)
+        {
+            return this.GetExportedValueCore<T>(contractName, ImportCardinality.ZeroOrOne);
+        }
+
+        /// <summary>
+        ///     Returns the exported values with the contract name derived from the specified type 
+        ///     parameter.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the exported value to return. The contract name is also 
+        ///     derived from this type parameter.
+        /// </typeparam>
+        /// <returns>
+        ///     An <see cref="Collection{T}"/> containing the exported values with the contract name 
+        ///     derived from the specified type parameter, if found; otherwise, an empty 
+        ///     <see cref="Collection{T}"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         The contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="CompositionContractMismatchException">
+        ///     One or more of the underlying exported values cannot be cast to 
+        ///     <typeparamref name="T"/>.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will 
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        public IEnumerable<T> GetExportedValues<T>()
+        {
+            return this.GetExportedValues<T>((string)null);
+        }
+
+        /// <summary>
+        ///     Returns the exported values with the specified contract name.
+        /// </summary>
+        /// <typeparam name="T">
+        ///     The type of the exported value to return.
+        /// </typeparam>
+        /// <param name="contractName">
+        ///     A <see cref="String"/> containing the contract name of the exported values to 
+        ///     return; or <see langword="null"/> or an empty string ("") to use the default 
+        ///     contract name.
+        /// </param>
+        /// <returns>
+        ///     An <see cref="Collection{T}"/> containing the exported values with the specified 
+        ///     contract name, if found; otherwise, an empty <see cref="Collection{T}"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on <typeparamref name="T"/>.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        /// <exception cref="CompositionContractMismatchException">
+        ///     One or more of the underlying exported values cannot be cast to 
+        ///     <typeparamref name="T"/>.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="CompositionContainer"/> has been disposed of.
+        /// </exception>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will 
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        public IEnumerable<T> GetExportedValues<T>(string contractName)
+        {
+            return this.GetExportedValuesCore<T>(contractName);
+        }
+
+        private IEnumerable<T> GetExportedValuesCore<T>(string contractName)
+        {
+            IEnumerable<Export> exports = this.GetExportsCore(typeof(T), (Type)null, contractName, ImportCardinality.ZeroOrMore);
+
+            Collection<T> result = new Collection<T>();
+            foreach (Export export in exports)
+            {
+                result.Add(ExportServices.GetCastedExportedValue<T>(export));
+            }
+            return result;
+        }
+
+        private T GetExportedValueCore<T>(string contractName, ImportCardinality cardinality)
+        {
+            Assumes.IsTrue(cardinality.IsAtMostOne());
+
+            Export export = this.GetExportsCore(typeof(T), (Type)null, contractName, cardinality).SingleOrDefault();
+
+            return (export != null) ? ExportServices.GetCastedExportedValue<T>(export) : default(T);
+        }
+
+        private IEnumerable<Lazy<T>> GetExportsCore<T>(string contractName)
+        {
+            IEnumerable<Export> exports = this.GetExportsCore(typeof(T), (Type)null, contractName, ImportCardinality.ZeroOrMore);
+
+            Collection<Lazy<T>> result = new Collection<Lazy<T>>();
+            foreach (Export export in exports)
+            {
+                result.Add(ExportServices.CreateStronglyTypedLazyOfT<T>(export));
+            }
+            return result;
+        }
+
+        private IEnumerable<Lazy<T, TMetadataView>> GetExportsCore<T, TMetadataView>(string contractName)
+        {
+            IEnumerable<Export> exports = this.GetExportsCore(typeof(T), typeof(TMetadataView), contractName, ImportCardinality.ZeroOrMore);
+
+            Collection<Lazy<T, TMetadataView>> result = new Collection<Lazy<T, TMetadataView>>();
+            foreach (Export export in exports)
+            {
+                result.Add(ExportServices.CreateStronglyTypedLazyOfTM<T, TMetadataView>(export));
+            }
+            return result;
+        }
+
+        private Lazy<T, TMetadataView> GetExportCore<T, TMetadataView>(string contractName)
+        {
+            Export export = this.GetExportsCore(typeof(T), typeof(TMetadataView), contractName, ImportCardinality.ExactlyOne).SingleOrDefault();
+
+            return (export != null) ? ExportServices.CreateStronglyTypedLazyOfTM<T, TMetadataView>(export) : null;
+        }
+
+        private Lazy<T> GetExportCore<T>(string contractName)
+        {
+            Export export = this.GetExportsCore(typeof(T), null, contractName, ImportCardinality.ExactlyOne).SingleOrDefault();
+
+            return (export != null) ? ExportServices.CreateStronglyTypedLazyOfT<T>(export) : null;
+        }
+
+        private IEnumerable<Export> GetExportsCore(Type type, Type metadataViewType, string contractName, ImportCardinality cardinality)
+        {
+            // Only 'type' cannot be null - the other parameters have sensible defaults.
+            Requires.NotNull(type, "type");
+
+            if (string.IsNullOrEmpty(contractName))
+            {
+                contractName = AttributedModelServices.GetContractName(type);
+            }
+
+            if (metadataViewType == null)
+            {
+                metadataViewType = ExportServices.DefaultMetadataViewType;
+            }
+
+            if (!MetadataViewProvider.IsViewTypeValid(metadataViewType))
+            {
+                throw new InvalidOperationException(string.Format(CultureInfo.CurrentCulture, Strings.InvalidMetadataView, metadataViewType.Name));
+            }
+
+            ImportDefinition importDefinition = BuildImportDefinition(type, metadataViewType, contractName, cardinality);
+            return this.GetExports(importDefinition, null);
+        }
+
+        private static ImportDefinition BuildImportDefinition(Type type, Type metadataViewType, string contractName, ImportCardinality cardinality)
+        {
+            Assumes.NotNull(type, metadataViewType, contractName);
+
+            IEnumerable<KeyValuePair<string, Type>> requiredMetadata = CompositionServices.GetRequiredMetadata(metadataViewType);
+            IDictionary<string, object> metadata = CompositionServices.GetImportMetadata(type, null);
+
+            string requiredTypeIdentity = null;
+            if (type != typeof(object))
+            {
+                requiredTypeIdentity = AttributedModelServices.GetTypeIdentity(type);
+            }
+
+            return new ContractBasedImportDefinition(contractName, requiredTypeIdentity, requiredMetadata, cardinality, false, true, CreationPolicy.Any, metadata);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ExportProvider.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ExportProvider.cs
new file mode 100644
index 00000000000..a2c8bbb3766
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ExportProvider.cs
@@ -0,0 +1,235 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.Contracts;
+using System.Globalization;
+using System.Linq;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    /// <summary>
+    ///     Defines the <see langword="abstract"/> base class for export providers, which provide
+    ///     methods for retrieving <see cref="Export"/> objects.
+    /// </summary>
+    public abstract partial class ExportProvider
+    {
+        private static readonly Export[] EmptyExports = new Export[] { };
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ExportProvider"/> class.
+        /// </summary>
+        protected ExportProvider()
+        {
+        }
+
+        /// <summary>
+        ///     Occurs when the exports in the <see cref="ExportProvider"/> have changed.
+        /// </summary>
+        public event EventHandler<ExportsChangeEventArgs> ExportsChanged;
+
+        /// <summary>
+        ///     Occurs when the exports in the <see cref="ExportProvider"/> are changing.
+        /// </summary>
+        public event EventHandler<ExportsChangeEventArgs> ExportsChanging;
+
+        /// <summary>
+        ///     Returns all exports that match the conditions of the specified import.
+        /// </summary>
+        /// <param name="definition">
+        ///     The <see cref="ImportDefinition"/> that defines the conditions of the 
+        ///     <see cref="Export"/> objects to get.
+        /// </param>
+        /// <result>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="Export"/> objects that match 
+        ///     the conditions defined by <see cref="ImportDefinition"/>, if found; otherwise, an 
+        ///     empty <see cref="IEnumerable{T}"/>.
+        /// </result>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="definition"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ImportCardinalityMismatchException">
+        ///     <para>
+        ///         <see cref="ImportDefinition.Cardinality"/> is <see cref="ImportCardinality.ExactlyOne"/> and 
+        ///         there are zero <see cref="Export"/> objects that match the conditions of the specified 
+        ///         <see cref="ImportDefinition"/>.
+        ///     </para>
+        ///     -or-
+        ///     <para>
+        ///         <see cref="ImportDefinition.Cardinality"/> is <see cref="ImportCardinality.ZeroOrOne"/> or 
+        ///         <see cref="ImportCardinality.ExactlyOne"/> and there are more than one <see cref="Export"/> 
+        ///         objects that match the conditions of the specified <see cref="ImportDefinition"/>.
+        ///     </para>
+        /// </exception>
+        public IEnumerable<Export> GetExports(ImportDefinition definition)
+        {
+            return GetExports(definition, null);
+        }
+
+        /// <summary>
+        ///     Returns all exports that match the conditions of the specified import.
+        /// </summary>
+        /// <param name="definition">
+        ///     The <see cref="ImportDefinition"/> that defines the conditions of the 
+        ///     <see cref="Export"/> objects to get.
+        /// </param>
+        /// <result>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="Export"/> objects that match 
+        ///     the conditions defined by <see cref="ImportDefinition"/>, if found; otherwise, an 
+        ///     empty <see cref="IEnumerable{T}"/>.
+        /// </result>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="definition"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ImportCardinalityMismatchException">
+        ///     <para>
+        ///         <see cref="ImportDefinition.Cardinality"/> is <see cref="ImportCardinality.ExactlyOne"/> and 
+        ///         there are zero <see cref="Export"/> objects that match the conditions of the specified 
+        ///         <see cref="ImportDefinition"/>.
+        ///     </para>
+        ///     -or-
+        ///     <para>
+        ///         <see cref="ImportDefinition.Cardinality"/> is <see cref="ImportCardinality.ZeroOrOne"/> or 
+        ///         <see cref="ImportCardinality.ExactlyOne"/> and there are more than one <see cref="Export"/> 
+        ///         objects that match the conditions of the specified <see cref="ImportDefinition"/>.
+        ///     </para>
+        /// </exception>
+        public IEnumerable<Export> GetExports(ImportDefinition definition, AtomicComposition atomicComposition)
+        {
+            Requires.NotNull(definition, "definition");
+            Contract.Ensures(Contract.Result<IEnumerable<Export>>() != null);
+
+            IEnumerable<Export> exports;
+            ExportCardinalityCheckResult result = this.TryGetExportsCore(definition, atomicComposition, out exports);
+            switch(result)
+            {
+                case ExportCardinalityCheckResult.Match:
+                    return exports;
+                case ExportCardinalityCheckResult.NoExports:
+                    throw new ImportCardinalityMismatchException(string.Format(CultureInfo.CurrentCulture, Strings.CardinalityMismatch_NoExports, definition.ToString()));
+                default:
+                    Assumes.IsTrue(result == ExportCardinalityCheckResult.TooManyExports);
+                    throw new ImportCardinalityMismatchException(string.Format(CultureInfo.CurrentCulture, Strings.CardinalityMismatch_TooManyExports, definition.ToString()));
+            }
+        }
+
+        /// <summary>
+        ///     Returns all exports that match the conditions of the specified import.
+        /// </summary>
+        /// <param name="definition">
+        ///     The <see cref="ImportDefinition"/> that defines the conditions of the 
+        ///     <see cref="Export"/> objects to get.
+        /// </param>
+        /// <param name="exports">
+        ///     When this method returns, contains an <see cref="IEnumerable{T}"/> of <see cref="Export"/> 
+        ///     objects that match the conditions defined by <see cref="ImportDefinition"/>, if found; 
+        ///     otherwise, an empty <see cref="IEnumerable{T}"/>.
+        /// </param>
+        /// <returns>
+        ///     <see langword="true"/> if <see cref="ImportDefinition.Cardinality"/> is 
+        ///     <see cref="ImportCardinality.ZeroOrOne"/> or <see cref="ImportCardinality.ZeroOrMore"/> and 
+        ///     there are zero <see cref="Export"/> objects that match the conditions of the specified 
+        ///     <see cref="ImportDefinition"/>. <see langword="true"/> if 
+        ///     <see cref="ImportDefinition.Cardinality"/> is <see cref="ImportCardinality.ZeroOrOne"/> or 
+        ///     <see cref="ImportCardinality.ExactlyOne"/> and there is exactly one <see cref="Export"/> 
+        ///     that matches the conditions of the specified <see cref="ImportDefinition"/>; otherwise, 
+        ///     <see langword="false"/>.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="definition"/> is <see langword="null"/>.
+        /// </exception>
+        public bool TryGetExports(ImportDefinition definition, AtomicComposition atomicComposition, out IEnumerable<Export> exports)
+        {
+            Requires.NotNull(definition, "definition");
+
+            exports = null;
+            ExportCardinalityCheckResult result = this.TryGetExportsCore(definition, atomicComposition, out exports);
+            return (result == ExportCardinalityCheckResult.Match);
+        }
+    
+        /// <summary>
+        ///     Returns all exports that match the constraint defined by the specified definition.
+        /// </summary>
+        /// <param name="definition">
+        ///     The <see cref="ImportDefinition"/> that defines the conditions of the 
+        ///     <see cref="Export"/> objects to return.
+        /// </param>
+        /// <result>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="Export"/> objects that match 
+        ///     the conditions defined by <see cref="ImportDefinition"/>, if found; otherwise, an 
+        ///     empty <see cref="IEnumerable{T}"/>.
+        /// </result>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Overriders of this method should not treat cardinality-related mismatches 
+        ///         as errors, and should not throw exceptions in those cases. For instance,
+        ///         if <see cref="ImportDefinition.Cardinality"/> is <see cref="ImportCardinality.ExactlyOne"/> 
+        ///         and there are zero <see cref="Export"/> objects that match the conditions of the 
+        ///         specified <see cref="ImportDefinition"/>, an <see cref="IEnumerable{T}"/> should be returned.
+        ///     </note>
+        /// </remarks>
+        protected abstract IEnumerable<Export> GetExportsCore(ImportDefinition definition, AtomicComposition atomicComposition);
+
+        /// <summary>
+        ///     Raises the <see cref="ExportsChanged"/> event.
+        /// </summary>
+        /// <param name="e">
+        ///     An <see cref="ExportsChangeEventArgs"/> containing the data for the event.
+        /// </param>
+        protected virtual void OnExportsChanged(ExportsChangeEventArgs e)
+        {
+            EventHandler<ExportsChangeEventArgs> changedEvent = this.ExportsChanged;
+            if (changedEvent != null)
+            {
+                CompositionResult result = CompositionServices.TryFire(changedEvent, this, e);
+                result.ThrowOnErrors(e.AtomicComposition);
+            }
+        }
+
+        /// <summary>
+        ///     Raises the <see cref="ExportsChanging"/> event.
+        /// </summary>
+        /// <param name="e">
+        ///     An <see cref="ExportsChangeEventArgs"/> containing the data for the event.
+        /// </param>
+        protected virtual void OnExportsChanging(ExportsChangeEventArgs e)
+        {
+            EventHandler<ExportsChangeEventArgs> changingEvent = this.ExportsChanging;
+            if (changingEvent != null)
+            {
+                CompositionResult result = CompositionServices.TryFire(changingEvent, this, e);
+                result.ThrowOnErrors(e.AtomicComposition);
+            }
+        }
+
+        private ExportCardinalityCheckResult TryGetExportsCore(ImportDefinition definition, AtomicComposition atomicComposition, out IEnumerable<Export> exports)
+        {
+            Assumes.NotNull(definition);
+
+            exports = this.GetExportsCore(definition, atomicComposition);
+
+            var checkResult = ExportServices.CheckCardinality(definition, exports);
+
+            // Export providers treat >1 match as zero for cardinality 0-1 imports
+            // If this policy is moved we need to revisit the assumption that the
+            // ImportEngine made during previewing the only required imports to 
+            // now also preview optional imports.
+            if (checkResult == ExportCardinalityCheckResult.TooManyExports &&
+                definition.Cardinality == ImportCardinality.ZeroOrOne)
+            {
+                checkResult = ExportCardinalityCheckResult.Match;
+                exports = null;
+            }
+
+            if (exports == null)
+            {
+                exports = EmptyExports;
+            }
+
+            return checkResult;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ExportsChangeEventArgs.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ExportsChangeEventArgs.cs
new file mode 100644
index 00000000000..f53eb9e029f
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ExportsChangeEventArgs.cs
@@ -0,0 +1,128 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.Contracts;
+using System.Linq;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    /// <summary>
+    ///     Provides data for the <see cref="ExportProvider.ExportsChanged"/> and 
+    ///     <see cref="ExportProvider.ExportsChanging"/> events.
+    /// </summary>
+    public class ExportsChangeEventArgs : EventArgs
+    {
+        private readonly IEnumerable<ExportDefinition> _addedExports;
+        private readonly IEnumerable<ExportDefinition> _removedExports;
+        private IEnumerable<string> _changedContractNames = null;
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ExportsChangeEventArgs"/> class with 
+        ///     the specified changed export definitions.
+        /// </summary>
+        /// <param name="addedExports">
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="ExportDefinition"/>s of the exports
+        ///     that have been added.
+        /// </param>
+        /// <param name="removedExports">
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="ExportDefinition"/>s of the exports
+        ///     that have been removed.
+        /// </param>
+        /// <param name="atomicComposition">
+        ///     A <see cref="AtomicComposition"/> representing all tentative changes that will
+        ///     be completed if the change is successful, or discarded if it is not. 
+        ///     <see langword="null"/> if being applied outside a <see cref="AtomicComposition"/> 
+        ///     or during a <see cref="ExportProvider.ExportsChanged"/> event.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="addedExports"/> or <paramref name="removedExports"/> is <see langword="null"/>.
+        /// </exception>
+        public ExportsChangeEventArgs(IEnumerable<ExportDefinition> addedExports,
+                IEnumerable<ExportDefinition> removedExports, AtomicComposition atomicComposition)
+        {
+            Requires.NotNull(addedExports, "addedExports");
+            Requires.NotNull(removedExports, "removedExports");
+
+            this._addedExports = addedExports.AsArray();
+            this._removedExports = removedExports.AsArray();
+            this.AtomicComposition = atomicComposition;
+        }
+
+        /// <summary>
+        ///     Gets the export definitions for the exports that have been added.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="IEnumerable{T}"/> of ExportDefinitions representing 
+        ///     the exports that have been added to the <see cref="CompositionContainer"/>.
+        /// </value>
+        public IEnumerable<ExportDefinition> AddedExports 
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<IEnumerable<ExportDefinition>>() != null);
+
+                return this._addedExports;
+            }
+        }
+
+        /// <summary>
+        ///     Gets the export definitions for the exports that have been removed.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="IEnumerable{T}"/> of ExportDefinitions representing 
+        ///     the exports that have been added to the <see cref="CompositionContainer"/>.
+        /// </value>
+        public IEnumerable<ExportDefinition> RemovedExports 
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<IEnumerable<ExportDefinition>>() != null);
+
+                return this._removedExports;
+            }
+        }
+
+        /// <summary>
+        ///     Gets the contract names of the exports that have changed.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="IEnumerable{T}"/> of strings representing the contract names of 
+        ///     the exports that have changed in the <see cref="CompositionContainer"/>.
+        /// </value>
+        public IEnumerable<string> ChangedContractNames 
+        {
+            get
+            {
+                if (this._changedContractNames == null)
+                {
+                    this._changedContractNames = this.AddedExports
+                        .Concat(this.RemovedExports)
+                        .Select(export => export.ContractName)
+                        .Distinct()
+                        .ToArray();
+                }
+                return this._changedContractNames;
+            }
+        }
+
+        /// <summary>
+        ///     Gets the atomicComposition, if any, that this change applies to.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="AtomicComposition"/> that this set of changes applies too. 
+        ///     
+        ///     It can be <see langword="null"/> if the changes are being applied outside a 
+        ///     <see cref="AtomicComposition"/> or during a 
+        ///     <see cref="ExportProvider.ExportsChanged"/> event.
+        ///     
+        ///     When the value is non-null it should be used to record temporary changed state
+        ///     and actions that will be executed when the atomicComposition is completeed.
+        /// </value>
+        public AtomicComposition AtomicComposition { get; private set; }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.DependenciesTraversal.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.DependenciesTraversal.cs
new file mode 100644
index 00000000000..062bd1e34bf
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.DependenciesTraversal.cs
@@ -0,0 +1,96 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Linq;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class FilteredCatalog
+    {
+        internal class DependenciesTraversal : IComposablePartCatalogTraversal
+        {
+            private IEnumerable<ComposablePartDefinition> _parts;
+            private Func<ImportDefinition, bool> _importFilter;
+            private Dictionary<string, List<ComposablePartDefinition>> _exportersIndex;
+
+            public DependenciesTraversal(FilteredCatalog catalog, Func<ImportDefinition, bool> importFilter)
+            {
+                Assumes.NotNull(catalog);
+                Assumes.NotNull(importFilter);
+
+                this._parts = catalog._innerCatalog;
+                this._importFilter = importFilter;
+            }
+
+            public void Initialize()
+            {
+                this.BuildExportersIndex();
+            }
+
+            private void BuildExportersIndex()
+            {
+                this._exportersIndex = new Dictionary<string, List<ComposablePartDefinition>>();
+                foreach (ComposablePartDefinition part in this._parts)
+                {
+                    foreach (var export in part.ExportDefinitions)
+                    {
+                        this.AddToExportersIndex(export.ContractName, part);
+                    }
+                }
+            }
+
+            private void AddToExportersIndex(string contractName, ComposablePartDefinition part)
+            {
+                List<ComposablePartDefinition> parts = null;
+                if (!this._exportersIndex.TryGetValue(contractName, out parts))
+                {
+                    parts = new List<ComposablePartDefinition>();
+                    this._exportersIndex.Add(contractName, parts);
+                }
+                parts.Add(part);
+            }
+
+            public bool TryTraverse(ComposablePartDefinition part, out IEnumerable<ComposablePartDefinition> reachableParts)
+            {
+                reachableParts = null;
+                List<ComposablePartDefinition> reachablePartList = null;
+
+                // Go through all part imports
+                foreach (ImportDefinition import in part.ImportDefinitions.Where(this._importFilter))
+                {
+                    // Find all parts that we know will import each export
+                    List<ComposablePartDefinition> candidateReachableParts = null;
+                    foreach (var contractName in import.GetCandidateContractNames(part))
+                    {
+                        if (this._exportersIndex.TryGetValue(contractName, out candidateReachableParts))
+                        {
+                            // find if they actually match
+                            foreach (var candidateReachablePart in candidateReachableParts)
+                            {
+                                foreach (ExportDefinition export in candidateReachablePart.ExportDefinitions)
+                                {
+                                    if (import.IsImportDependentOnPart(candidateReachablePart, export, part.IsGeneric() != candidateReachablePart.IsGeneric()))
+                                    {
+                                        if (reachablePartList == null)
+                                        {
+                                            reachablePartList = new List<ComposablePartDefinition>();
+                                        }
+                                        reachablePartList.Add(candidateReachablePart);
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+
+                reachableParts = reachablePartList;
+                return (reachableParts != null);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.DependentsTraversal.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.DependentsTraversal.cs
new file mode 100644
index 00000000000..e4593f18da4
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.DependentsTraversal.cs
@@ -0,0 +1,103 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Linq;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class FilteredCatalog
+    {
+        /// <summary>
+        /// Implementation of IComposablePartTraversal supporting the Dependents traveral pattern.
+        /// The implementation is optimized for a situation when the traversal is expected to be rather short-lived - that is,
+        /// if the chains of dependecies are rather small. To achieve that we do a very minimal structure prep upfront - merely creating a contract-based
+        /// index of imports - and the verify the full match of imports during the traversal. Given that most parts have a very few imports this should perform well.
+        /// </summary>
+        internal class DependentsTraversal : IComposablePartCatalogTraversal
+        {
+            private IEnumerable<ComposablePartDefinition> _parts;
+            private Func<ImportDefinition, bool> _importFilter;
+            private Dictionary<string, List<ComposablePartDefinition>> _importersIndex;
+
+            public DependentsTraversal(FilteredCatalog catalog, Func<ImportDefinition, bool> importFilter)
+            {
+                Assumes.NotNull(catalog);
+                Assumes.NotNull(importFilter);
+
+                this._parts = catalog._innerCatalog;
+                this._importFilter = importFilter;
+            }
+
+            public void Initialize()
+            {
+                this.BuildImportersIndex();
+            }
+
+            private void BuildImportersIndex()
+            {
+                this._importersIndex = new Dictionary<string, List<ComposablePartDefinition>>();
+                foreach (ComposablePartDefinition part in this._parts)
+                {
+                    foreach (var import in part.ImportDefinitions)
+                    {
+                        foreach (var contractName in import.GetCandidateContractNames(part))
+                        {
+                            this.AddToImportersIndex(contractName, part);
+                        }
+                    }
+                }
+            }
+
+
+            private void AddToImportersIndex(string contractName, ComposablePartDefinition part)
+            {
+                List<ComposablePartDefinition> parts = null;
+                if (!this._importersIndex.TryGetValue(contractName, out parts))
+                {
+                    parts = new List<ComposablePartDefinition>();
+                    this._importersIndex.Add(contractName, parts);
+                }
+                parts.Add(part);
+            }
+
+            public bool TryTraverse(ComposablePartDefinition part, out IEnumerable<ComposablePartDefinition> reachableParts)
+            {
+                reachableParts = null;
+                List<ComposablePartDefinition> reachablePartList = null;
+
+                // Go through all part exports
+                foreach (ExportDefinition export in part.ExportDefinitions)
+                {
+                    // Find all parts that we know will import each export
+                    List<ComposablePartDefinition> candidateReachableParts = null;
+                    if (this._importersIndex.TryGetValue(export.ContractName, out candidateReachableParts))
+                    {
+                        // find if they actually match
+                        foreach (var candidateReachablePart in candidateReachableParts)
+                        {
+                            foreach (ImportDefinition import in candidateReachablePart.ImportDefinitions.Where(this._importFilter))
+                            {
+                                if (import.IsImportDependentOnPart(part, export, part.IsGeneric() != candidateReachablePart.IsGeneric()))
+                                {
+                                    if (reachablePartList == null)
+                                    {
+                                        reachablePartList = new List<ComposablePartDefinition>();
+                                    }
+                                    reachablePartList.Add(candidateReachablePart);
+                                }
+                            }
+                        }
+                    }
+                }
+
+                reachableParts = reachablePartList;
+                return (reachableParts != null);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.IComposablePartCatalogTraversal.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.IComposablePartCatalogTraversal.cs
new file mode 100644
index 00000000000..b2f3609c562
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.IComposablePartCatalogTraversal.cs
@@ -0,0 +1,27 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Linq;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class FilteredCatalog
+    {
+        /// <summary>
+        /// This is designed to traverse a set of parts based on whatever pattern. There are no real expectations
+        /// as to what the pattern is and what properties is posseses
+        /// NOTE : we both with this interface - as opposed to just a simple delegate - due to minute performance reasons, 
+        /// as this will be invoked very often. Also, each traversal is typically associated with a big state bag, which is
+        /// easier to associte with an explicit implementation as opposed to an implicit closure.
+        /// </summary>
+        internal interface IComposablePartCatalogTraversal
+        {
+            void Initialize();
+            bool TryTraverse(ComposablePartDefinition part, out IEnumerable<ComposablePartDefinition> reachableParts);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.Traversal.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.Traversal.cs
new file mode 100644
index 00000000000..76a59ebb2a5
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.Traversal.cs
@@ -0,0 +1,134 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Linq;
+using System.Threading;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class FilteredCatalog
+    {
+        /// <summary>
+        /// Creates a new instance of the <see cref="FilteredCatalog"/> that conatains all the parts from the orignal filtered catalog and all their dependecies.
+        /// </summary>
+        /// <returns></returns>
+        public FilteredCatalog IncludeDependencies()
+        {
+            return this.IncludeDependencies(i => i.Cardinality == ImportCardinality.ExactlyOne);
+        }
+
+        /// <summary>
+        /// Creates a new instance of the <see cref="FilteredCatalog"/> that conatains all the parts from the orignal filtered catalog and all their dependencies that 
+        /// can be reached via imports that match the specified filter.
+        /// </summary>
+        /// <param name="importFilter">The import filter.</param>
+        /// <returns></returns>
+        public FilteredCatalog IncludeDependencies(Func<ImportDefinition, bool> importFilter)
+        {
+            Requires.NotNull(importFilter, "importFilter");
+            this.ThrowIfDisposed();
+
+            return Traverse(new DependenciesTraversal(this, importFilter));
+        }
+
+        /// <summary>
+        /// Creates a new instance of the <see cref="FilteredCatalog"/> that conatains all the parts from the orignal filtered catalog and all their dependents.
+        /// </summary>
+        /// <returns></returns>
+        public FilteredCatalog IncludeDependents()
+        {
+            return this.IncludeDependents(i => i.Cardinality == ImportCardinality.ExactlyOne);
+        }
+
+        /// <summary>
+        /// Creates a new instance of the <see cref="FilteredCatalog"/> that conatains all the parts from the orignal filtered catalog and all their dependents that 
+        /// can be reached via imports that match the specified filter.
+        /// </summary>
+        /// <param name="importFilter">The import filter.</param>
+        /// <returns></returns>
+        public FilteredCatalog IncludeDependents(Func<ImportDefinition, bool> importFilter)
+        {
+            Requires.NotNull(importFilter, "importFilter");
+            this.ThrowIfDisposed();
+
+            return Traverse(new DependentsTraversal(this, importFilter));
+        }
+
+        private FilteredCatalog Traverse(IComposablePartCatalogTraversal traversal)
+        {
+            Assumes.NotNull(traversal);
+
+            // we make sure that the underlyiong catalog cannot change while we are doing the trasversal
+            // After thaty traversal is done, the freeze is lifted, and the catalog is free to change, but the changes 
+            // cannot affect partitioning 
+            this.FreezeInnerCatalog();
+
+            try
+            {
+                traversal.Initialize();
+                var traversalClosure = GetTraversalClosure(this._innerCatalog.Where(this._filter), traversal);
+                return new FilteredCatalog(this._innerCatalog, p => traversalClosure.Contains(p));
+            }
+            finally
+            {
+                this.UnfreezeInnerCatalog();
+            }
+        }
+
+        private static HashSet<ComposablePartDefinition> GetTraversalClosure(IEnumerable<ComposablePartDefinition> parts, IComposablePartCatalogTraversal traversal)
+        {
+            Assumes.NotNull(traversal);
+
+            var traversedParts = new HashSet<ComposablePartDefinition>();
+            GetTraversalClosure(parts, traversedParts, traversal);
+            return traversedParts;
+        }
+
+        private static void GetTraversalClosure(IEnumerable<ComposablePartDefinition> parts, HashSet<ComposablePartDefinition> traversedParts, IComposablePartCatalogTraversal traversal)
+        {
+            foreach (var part in parts)
+            {
+                if (traversedParts.Add(part))
+                {
+                    IEnumerable<ComposablePartDefinition> partsToTraverse = null;
+                    if (traversal.TryTraverse(part, out partsToTraverse))
+                    {
+                        GetTraversalClosure(partsToTraverse, traversedParts, traversal);
+                    }
+                }
+            }
+        }
+
+
+        private void FreezeInnerCatalog()
+        {
+            INotifyComposablePartCatalogChanged innerNotifyCatalog = this._innerCatalog as INotifyComposablePartCatalogChanged;
+            if (innerNotifyCatalog != null)
+            {
+                innerNotifyCatalog.Changing += ThrowOnRecomposition;
+            }
+        }
+
+        private void UnfreezeInnerCatalog()
+        {
+            INotifyComposablePartCatalogChanged innerNotifyCatalog = this._innerCatalog as INotifyComposablePartCatalogChanged;
+            if (innerNotifyCatalog != null)
+            {
+                innerNotifyCatalog.Changing -= ThrowOnRecomposition;
+            }
+        }
+
+        private static void ThrowOnRecomposition(object sender, ComposablePartCatalogChangeEventArgs e)
+        {
+            throw new ChangeRejectedException(); // TODO - text
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.cs
new file mode 100644
index 00000000000..eea7c7d296b
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/FilteredCatalog.cs
@@ -0,0 +1,260 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Linq;
+using System.Threading;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class FilteredCatalog : ComposablePartCatalog, INotifyComposablePartCatalogChanged
+    {
+        private Func<ComposablePartDefinition, bool> _filter;
+        private ComposablePartCatalog _innerCatalog;
+        private FilteredCatalog _complement;
+        private object _lock = new object();
+        private volatile bool _isDisposed = false;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FilteredCatalog"/> class.
+        /// </summary>
+        /// <param name="catalog">The catalog.</param>
+        /// <param name="filter">The filter.</param>
+        public FilteredCatalog(ComposablePartCatalog catalog, Func<ComposablePartDefinition, bool> filter) : 
+            this(catalog, filter, null)
+        {
+        }
+
+        internal FilteredCatalog(ComposablePartCatalog catalog, Func<ComposablePartDefinition, bool> filter, FilteredCatalog complement)
+        {
+            Requires.NotNull(catalog, "catalog");
+            Requires.NotNull(filter, "filter");
+
+            this._innerCatalog = catalog;
+            this._filter = (p) => filter.Invoke(p.GetGenericPartDefinition() ?? p);
+            this._complement = complement;
+
+            INotifyComposablePartCatalogChanged notifyCatalog = this._innerCatalog as INotifyComposablePartCatalogChanged;
+            if (notifyCatalog != null)
+            {
+                notifyCatalog.Changed += this.OnChangedInternal;
+                notifyCatalog.Changing += this.OnChangingInternal;
+            }
+        }
+
+
+        /// <summary>
+        /// Releases unmanaged and - optionally - managed resources
+        /// </summary>
+        /// <param name="disposing"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
+        protected override void Dispose(bool disposing)
+        {
+            try
+            {
+                if (disposing)
+                {
+                    if(!this._isDisposed)
+                    {
+                        INotifyComposablePartCatalogChanged notifyCatalog = null;
+                        try
+                        {
+                            lock (this._lock)
+                            {
+                                if (!this._isDisposed)
+                                {
+                                    this._isDisposed = true;
+                                    notifyCatalog = this._innerCatalog as INotifyComposablePartCatalogChanged;
+                                    this._innerCatalog = null;
+                                }
+                            }
+                        }
+                        finally
+                        {
+                            if (notifyCatalog != null)
+                            {
+                                notifyCatalog.Changed -= this.OnChangedInternal;
+                                notifyCatalog.Changing -= this.OnChangingInternal;
+                            }
+                        }
+                    }
+                }
+            }
+            finally
+            {
+                base.Dispose(disposing);
+            }
+        }
+
+        public override IEnumerator<ComposablePartDefinition> GetEnumerator()
+        {
+            return this._innerCatalog.Where(this._filter).GetEnumerator();
+        }
+
+        /// <summary>
+        /// Gets the complement.
+        /// </summary>
+        /// <value>The complement.</value>
+        public FilteredCatalog Complement
+        {
+            get
+            {
+                this.ThrowIfDisposed();
+
+                if (this._complement == null)
+                {
+                    FilteredCatalog complement = new FilteredCatalog(this._innerCatalog, p => !this._filter(p), this);
+                    lock (this._lock)
+                    {
+                        if (this._complement == null)
+                        {
+                            Thread.MemoryBarrier();
+                            this._complement = complement;
+                            complement = null;
+                        }
+                    }
+
+                    if (complement != null)
+                    {
+                        complement.Dispose();
+                    }
+                }
+
+                return this._complement;
+            }
+        }
+
+        /// <summary>
+        /// Returns the export definitions that match the constraint defined by the specified definition.
+        /// </summary>
+        /// <param name="definition">The <see cref="ImportDefinition"/> that defines the conditions of the
+        /// <see cref="ExportDefinition"/> objects to return.</param>
+        /// <returns>
+        /// An <see cref="IEnumerable{T}"/> of <see cref="Tuple{T1, T2}"/> containing the
+        /// <see cref="ExportDefinition"/> objects and their associated
+        /// <see cref="ComposablePartDefinition"/> for objects that match the constraint defined
+        /// by <paramref name="definition"/>.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        /// 	<paramref name="definition"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        /// The <see cref="ComposablePartCatalog"/> has been disposed of.
+        /// </exception>
+        /// <remarks>
+        /// 	<note type="inheritinfo">
+        /// Overriders of this property should never return <see langword="null"/>, if no
+        /// <see cref="ExportDefinition"/> match the conditions defined by
+        /// <paramref name="definition"/>, return an empty <see cref="IEnumerable{T}"/>.
+        /// </note>
+        /// </remarks>
+        public override IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>> GetExports(ImportDefinition definition)
+        {
+            this.ThrowIfDisposed();
+            Requires.NotNull(definition, "definition");
+
+            var exports = new List<Tuple<ComposablePartDefinition, ExportDefinition>>();
+            foreach(var export in this._innerCatalog.GetExports(definition))
+            {
+                if (this._filter(export.Item1))
+                {
+                    exports.Add(export);
+                }
+            }
+
+            return exports;
+        }
+
+        /// <summary>
+        /// Notify when the contents of the Catalog has changed.
+        /// </summary>
+        public event EventHandler<ComposablePartCatalogChangeEventArgs> Changed;
+
+
+        /// <summary>
+        /// Notify when the contents of the Catalog is changing.
+        /// </summary>
+        public event EventHandler<ComposablePartCatalogChangeEventArgs> Changing;
+
+
+        /// <summary>
+        /// Raises the <see cref="E:Changed"/> event.
+        /// </summary>
+        /// <param name="e">The <see cref="System.ComponentModel.Composition.Hosting.ComposablePartCatalogChangeEventArgs"/> instance containing the event data.</param>
+        protected virtual void OnChanged(ComposablePartCatalogChangeEventArgs e)
+        {
+            EventHandler<ComposablePartCatalogChangeEventArgs> changedEvent = this.Changed;
+            if (changedEvent != null)
+            {
+                changedEvent.Invoke(this, e);
+            }
+        }
+
+        /// <summary>
+        /// Raises the <see cref="E:Changing"/> event.
+        /// </summary>
+        /// <param name="e">The <see cref="System.ComponentModel.Composition.Hosting.ComposablePartCatalogChangeEventArgs"/> instance containing the event data.</param>
+        protected virtual void OnChanging(ComposablePartCatalogChangeEventArgs e)
+        {
+            EventHandler<ComposablePartCatalogChangeEventArgs> changingEvent = this.Changing;
+            if (changingEvent != null)
+            {
+                changingEvent.Invoke(this, e);
+            }
+        }
+
+        private void OnChangedInternal(object sender, ComposablePartCatalogChangeEventArgs e)
+        {
+            var processedArgs = ProcessEventArgs(e);
+            if (processedArgs != null)
+            {
+                this.OnChanged(this.ProcessEventArgs(processedArgs));
+            }
+        }
+
+        private void OnChangingInternal(object sender, ComposablePartCatalogChangeEventArgs e)
+        {
+            var processedArgs = ProcessEventArgs(e);
+            if (processedArgs != null)
+            {
+                this.OnChanging(this.ProcessEventArgs(processedArgs));
+            }
+        }
+
+        private ComposablePartCatalogChangeEventArgs ProcessEventArgs(ComposablePartCatalogChangeEventArgs e)
+        {
+            // the constructor for ComposablePartCatalogChangeEventArgs takes a snapshot of the arguments, so we don't have to
+            var result = new ComposablePartCatalogChangeEventArgs(
+                e.AddedDefinitions.Where(this._filter),
+                e.RemovedDefinitions.Where(this._filter),
+                e.AtomicComposition);
+
+            // Only fire if we need to
+            if (result.AddedDefinitions.FastAny() || result.RemovedDefinitions.FastAny())
+            {
+                return result;
+            }
+            else
+            {
+                return null;
+            }
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/INotifyComposablePartCatalogChanged.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/INotifyComposablePartCatalogChanged.cs
new file mode 100644
index 00000000000..28d013b1744
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/INotifyComposablePartCatalogChanged.cs
@@ -0,0 +1,19 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    /// <summary>
+    ///     Notifications when a ComposablePartCatalog changes.
+    /// </summary>
+    public interface INotifyComposablePartCatalogChanged
+    {
+        event EventHandler<ComposablePartCatalogChangeEventArgs> Changed;
+        event EventHandler<ComposablePartCatalogChangeEventArgs> Changing;
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.EngineContext.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.EngineContext.cs
new file mode 100644
index 00000000000..d5fb427d05b
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.EngineContext.cs
@@ -0,0 +1,84 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class ImportEngine 
+    {
+        /// <summary>
+        ///     Used to wrap the start and stop of enforcing export changes don't
+        ///     break required imports. This context is stored in a AtomicComposition.
+        /// </summary>
+        private class EngineContext
+        {
+            private ImportEngine _importEngine;
+            private List<PartManager> _addedPartManagers = new List<PartManager>();
+            private List<PartManager> _removedPartManagers = new List<PartManager>();
+            private EngineContext _parentEngineContext;
+
+            public EngineContext(ImportEngine importEngine, EngineContext parentEngineContext)
+            {
+                this._importEngine = importEngine;
+                this._parentEngineContext = parentEngineContext;
+            }
+
+            public void AddPartManager(PartManager part)
+            {
+                Assumes.NotNull(part);
+                if (!this._removedPartManagers.Remove(part))
+                {
+                    this._addedPartManagers.Add(part);
+                }
+            }
+
+            public void RemovePartManager(PartManager part)
+            {
+                Assumes.NotNull(part);
+                if (!this._addedPartManagers.Remove(part))
+                {
+                    this._removedPartManagers.Add(part);
+                }
+            }
+
+            public IEnumerable<PartManager> GetAddedPartManagers()
+            {
+                if (this._parentEngineContext != null)
+                {
+                    return this._addedPartManagers.ConcatAllowingNull(this._parentEngineContext.GetAddedPartManagers());
+                }
+                return this._addedPartManagers;
+            }
+
+            public IEnumerable<PartManager> GetRemovedPartManagers()
+            {
+                if (this._parentEngineContext != null)
+                {
+                    return this._removedPartManagers.ConcatAllowingNull(this._parentEngineContext.GetRemovedPartManagers());
+                }
+                return this._removedPartManagers;
+            }
+
+            public void Complete()
+            {
+                foreach (var partManager in this._addedPartManagers)
+                {
+                    this._importEngine.StartSatisfyingImports(partManager, null);
+                }
+
+                foreach (var partManager in this._removedPartManagers)
+                {
+                    this._importEngine.StopSatisfyingImports(partManager, null);
+                }
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.PartManager.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.PartManager.cs
new file mode 100644
index 00000000000..2af4197c88e
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.PartManager.cs
@@ -0,0 +1,211 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class ImportEngine
+    {
+        /// <summary>
+        ///     Used by the <see cref="ImportEngine"/> to manage the composition of a given part.
+        ///     It stores things like the list of disposable exports used to satisfy the imports as
+        ///     well as the caching of the exports discovered during previewing of a part.
+        /// </summary>
+        private class PartManager
+        {
+            private Dictionary<ImportDefinition, List<IDisposable>> _importedDisposableExports;
+            private Dictionary<ImportDefinition, Export[]> _importCache;
+            private string[] _importedContractNames;
+            private ComposablePart _part;
+            private ImportState _state = ImportState.NoImportsSatisfied;
+            private readonly ImportEngine _importEngine;
+
+            public PartManager(ImportEngine importEngine, ComposablePart part)
+            {
+                this._importEngine = importEngine;
+                this._part = part;
+            }
+
+            public ComposablePart Part
+            {
+                get
+                {
+                    return this._part;
+                }
+            }
+
+            public ImportState State
+            {
+                get
+                {
+                    using (this._importEngine._lock.LockStateForRead())
+                    {
+                        return this._state;
+                    }
+                }
+                set
+                {
+                    using (this._importEngine._lock.LockStateForWrite())
+                    {
+                        this._state = value;
+                    }
+                }
+            }
+
+            public bool TrackingImports { get; set; }
+
+            public IEnumerable<string> GetImportedContractNames()
+            {
+                if (this.Part == null)
+                {
+                    return Enumerable.Empty<string>();
+                }
+
+                if (this._importedContractNames == null)
+                {
+                    this._importedContractNames = this.Part.ImportDefinitions.Select(import => import.ContractName ?? ImportDefinition.EmptyContractName).Distinct().ToArray();
+                }
+                return this._importedContractNames;
+            }
+
+            public CompositionResult TrySetImport(ImportDefinition import, IEnumerable<Export> exports)
+            {
+                try
+                {
+                    this.Part.SetImport(import, exports);
+                    UpdateDisposableDependencies(import, exports);
+                    return CompositionResult.SucceededResult;
+                }
+                catch (CompositionException ex)
+                {   // Pulling on one of the exports failed
+
+                    return new CompositionResult(
+                        ErrorBuilder.CreatePartCannotSetImport(Part, import, ex));
+                }
+                catch (ComposablePartException ex)
+                {   // Type mismatch between export and import
+
+                    return new CompositionResult(
+                        ErrorBuilder.CreatePartCannotSetImport(Part, import, ex));
+                }
+            }
+
+            public void SetSavedImport(ImportDefinition import, Export[] exports, AtomicComposition atomicComposition)
+            {
+                if (atomicComposition != null)
+                {
+                    var savedExports = this.GetSavedImport(import);
+
+                    // Add a revert action to revert the stored exports
+                    // in the case that this atomicComposition gets rolled back.
+                    atomicComposition.AddRevertAction(() =>
+                        this.SetSavedImport(import, savedExports, null));
+                }
+
+                if (this._importCache == null)
+                {
+                    this._importCache = new Dictionary<ImportDefinition, Export[]>();
+                }
+
+                this._importCache[import] = exports;
+            }
+
+            public Export[] GetSavedImport(ImportDefinition import)
+            {
+                Export[] exports = null;
+                if (this._importCache != null)
+                {
+                    // We don't care about the return value we just want the exports
+                    // and if it isn't present we just return the initialized null value
+                    this._importCache.TryGetValue(import, out exports);
+                }
+                return exports;
+            }
+
+            public void ClearSavedImports()
+            {
+                this._importCache = null;
+            }
+
+            public CompositionResult TryOnComposed()
+            {
+                try
+                {
+                    this.Part.Activate();
+                    return CompositionResult.SucceededResult;
+                }
+                catch (ComposablePartException ex)
+                {   // Type failed to be constructed, imports could not be set, etc
+                    return new CompositionResult(
+                        ErrorBuilder.CreatePartCannotActivate(this.Part, ex));
+                }
+            }
+
+            public void UpdateDisposableDependencies(ImportDefinition import, IEnumerable<Export> exports)
+            {
+                // Determine if there are any new disposable exports, optimizing for the most
+                // likely case, which is that there aren't any
+                List<IDisposable> disposableExports = null;
+                foreach (var disposableExport in exports.OfType<IDisposable>())
+                {
+                    if (disposableExports == null)
+                    {
+                        disposableExports = new List<IDisposable>();
+                    }
+                    disposableExports.Add(disposableExport);
+                }
+
+                // Dispose any existing references previously set on this import
+                List<IDisposable> oldDisposableExports = null;
+                if (this._importedDisposableExports != null &&
+                    this._importedDisposableExports.TryGetValue(import, out oldDisposableExports))
+                {
+                    oldDisposableExports.ForEach(disposable => disposable.Dispose());
+
+                    // If there aren't any replacements, get rid of the old storage
+                    if (disposableExports == null)
+                    {
+                        this._importedDisposableExports.Remove(import);
+                        if (!this._importedDisposableExports.FastAny())
+                        {
+                            this._importedDisposableExports = null;
+                        }
+
+                        return;
+                    }
+                }
+
+                // Record the new collection
+                if (disposableExports != null)
+                {
+                    if (this._importedDisposableExports == null)
+                    {
+                        this._importedDisposableExports = new Dictionary<ImportDefinition, List<IDisposable>>();
+                    }
+                    this._importedDisposableExports[import] = disposableExports;
+                }
+            }
+
+            public void DisposeAllDependencies()
+            {
+                if (this._importedDisposableExports != null)
+                {
+                    IEnumerable<IDisposable> dependencies = this._importedDisposableExports.Values
+                        .SelectMany(exports => exports);
+
+                    this._importedDisposableExports = null;
+
+                    dependencies.ForEach(disposableExport => disposableExport.Dispose());
+                }
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.RecompositionManager.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.RecompositionManager.cs
new file mode 100644
index 00000000000..ba1f98a77c9
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.RecompositionManager.cs
@@ -0,0 +1,159 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public partial class ImportEngine
+    {
+        /// <summary>
+        ///     Used by the <see cref="ImportEngine"/> to effiecently store and retrieve the list of parts
+        ///     that will be affected by changes to exports. This allows the <see cref="ImportEngine"/> to properly
+        ///     block breaking changes and also recompose imports as appropriate.
+        /// </summary>
+        private class RecompositionManager
+        {
+            private WeakReferenceCollection<PartManager> _partsToIndex = new WeakReferenceCollection<PartManager>();
+            private WeakReferenceCollection<PartManager> _partsToUnindex = new WeakReferenceCollection<PartManager>();
+            private Dictionary<string, WeakReferenceCollection<PartManager>> _partManagerIndex = new Dictionary<string, WeakReferenceCollection<PartManager>>();
+
+            public void AddPartToIndex(PartManager partManager)
+            {
+                this._partsToIndex.Add(partManager);
+            }
+
+            public void AddPartToUnindex(PartManager partManager)
+            {
+                this._partsToUnindex.Add(partManager);
+            }
+
+            public IEnumerable<PartManager> GetAffectedParts(IEnumerable<string> changedContractNames)
+            {
+                this.UpdateImportIndex();
+
+                List<PartManager> parts = new List<PartManager>();
+
+                parts.AddRange(GetPartsImporting(ImportDefinition.EmptyContractName));
+
+                foreach (string contractName in changedContractNames)
+                {
+                    parts.AddRange(GetPartsImporting(contractName));
+                }
+
+                return parts;
+            }
+
+            public static IEnumerable<ImportDefinition> GetAffectedImports(ComposablePart part, IEnumerable<ExportDefinition> changedExports)
+            {
+                return part.ImportDefinitions.Where(import => IsAffectedImport(import, changedExports));
+            }
+
+            private static bool IsAffectedImport(ImportDefinition import, IEnumerable<ExportDefinition> changedExports)
+            {
+                // This could be more efficient still if the export definitions were indexed by contract name,
+                // only worth revisiting if we need to squeeze more performance out of recomposition
+                foreach (var export in changedExports)
+                {
+                    if (import.IsConstraintSatisfiedBy(export))
+                    {
+                        return true;
+                    }
+                }
+               
+                return false;
+            }
+
+            public IEnumerable<PartManager> GetPartsImporting(string contractName)
+            {
+                WeakReferenceCollection<PartManager> partManagerList;
+                if (!this._partManagerIndex.TryGetValue(contractName, out partManagerList))
+                {
+                    return Enumerable.Empty<PartManager>();
+                }
+
+                return partManagerList.AliveItemsToList();
+            }
+
+            private void AddIndexEntries(PartManager partManager)
+            {
+                foreach (string contractName in partManager.GetImportedContractNames())
+                {
+                    WeakReferenceCollection<PartManager> indexEntries;
+                    if (!this._partManagerIndex.TryGetValue(contractName, out indexEntries))
+                    {
+                        indexEntries = new WeakReferenceCollection<PartManager>();
+                        this._partManagerIndex.Add(contractName, indexEntries);
+                    }
+
+                    if (!indexEntries.Contains(partManager))
+                    {
+                        indexEntries.Add(partManager);
+                    }
+                }
+            }
+
+            private void RemoveIndexEntries(PartManager partManager)
+            {
+                foreach (string contractName in partManager.GetImportedContractNames())
+                {
+                    WeakReferenceCollection<PartManager> indexEntries;
+                    if (this._partManagerIndex.TryGetValue(contractName, out indexEntries))
+                    {
+                        indexEntries.Remove(partManager);
+                        var aliveItems = indexEntries.AliveItemsToList();
+
+                        if (aliveItems.Count == 0)
+                        {
+                            this._partManagerIndex.Remove(contractName);
+                        }
+                    }
+                }
+            }
+
+            private void UpdateImportIndex()
+            {
+                var partsToIndex = this._partsToIndex.AliveItemsToList();
+                this._partsToIndex.Clear();
+
+                var partsToUnindex = this._partsToUnindex.AliveItemsToList();
+                this._partsToUnindex.Clear();
+
+                if (partsToIndex.Count == 0 && partsToUnindex.Count == 0)
+                {
+                    return;
+                }
+
+                foreach (var partManager in partsToIndex)
+                {
+                    var index = partsToUnindex.IndexOf(partManager);
+
+                    // If the same part is being added and removed we can ignore both
+                    if (index >= 0)
+                    {
+                        partsToUnindex[index] = null;
+                    }
+                    else
+                    {
+                        AddIndexEntries(partManager);
+                    }
+                }
+
+                foreach (var partManager in partsToUnindex)
+                {
+                    if (partManager != null)
+                    {
+                        RemoveIndexEntries(partManager);
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.cs
new file mode 100644
index 00000000000..7b0b04c0c1b
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportEngine.cs
@@ -0,0 +1,771 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    // This class guarantees thread-safety under the following conditions:
+    // - Each composition is executed on a single thread
+    // - No recomposition ever takes place
+    // - The class is created with isThreadSafe=true
+    public partial class ImportEngine : ICompositionService, IDisposable
+    {
+        private const int MaximumNumberOfCompositionIterations = 100;
+
+        private volatile bool _isDisposed;
+        private ExportProvider _sourceProvider;
+        private Stack<PartManager> _recursionStateStack = new Stack<PartManager>();
+        private ConditionalWeakTable<ComposablePart, PartManager> _partManagers = new ConditionalWeakTable<ComposablePart, PartManager>();
+        private RecompositionManager _recompositionManager = new RecompositionManager();
+        private readonly CompositionLock _lock = null;
+        private readonly CompositionOptions _compositionOptions;
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportEngine"/> class.
+        /// </summary>
+        /// <param name="sourceProvider">
+        ///     The <see cref="ExportProvider"/> which provides the 
+        ///     <see cref="ImportEngine"/> access to <see cref="Export"/>s. 
+        /// </param>
+        public ImportEngine(ExportProvider sourceProvider)
+            : this(sourceProvider, CompositionOptions.Default)
+        {
+        }
+
+        public ImportEngine(ExportProvider sourceProvider, bool isThreadSafe)
+            : this(sourceProvider, isThreadSafe ? CompositionOptions.IsThreadSafe : CompositionOptions.Default)
+        {
+        }
+
+        public ImportEngine(ExportProvider sourceProvider, CompositionOptions compositionOptions)
+        {
+            Requires.NotNull(sourceProvider, "sourceProvider");
+
+            this._compositionOptions = compositionOptions;
+            this._sourceProvider = sourceProvider;
+            this._sourceProvider.ExportsChanging += this.OnExportsChanging;
+            this._lock = new CompositionLock(compositionOptions.HasFlag(CompositionOptions.IsThreadSafe));
+        }
+
+        /// <summary>
+        ///     Previews all the required imports for the given <see cref="ComposablePart"/> to 
+        ///     ensure they can all be satisified. The preview does not actually set the imports
+        ///     only ensures that they exist in the source provider. If the preview succeeds then
+        ///     the <see cref="ImportEngine"/> also enforces that changes to exports in the source
+        ///     provider will not break any of the required imports. If this enforcement needs to be
+        ///     lifted for this part then <see cref="ReleaseImports"/> needs to be called for this
+        ///     <see cref="ComposablePart"/>.
+        /// </summary>
+        /// <param name="part">
+        ///     The <see cref="ComposablePart"/> to preview the required imports.
+        /// </param>
+        /// <param name="atomicComposition"></param>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during previewing and <paramref name="atomicComposition"/> is null. 
+        ///     <see cref="CompositionException.Errors"/> will contain a collection of errors that occurred.
+        ///     The pre-existing composition is in an unknown state, depending on the errors that occured.
+        /// </exception>
+        /// <exception cref="ChangeRejectedException">
+        ///     An error occurred during the previewing and <paramref name="atomicComposition"/> is not null.
+        ///     <see cref="CompositionException.Errors"/> will contain a collection of errors that occurred.
+        ///     The pre-existing composition remains in valid state.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ImportEngine"/> has been disposed of.
+        /// </exception>
+        public void PreviewImports(ComposablePart part, AtomicComposition atomicComposition)
+        {
+            this.ThrowIfDisposed();
+
+            Requires.NotNull(part, "part");
+
+            // Do not do any previewing if SilentRejection is disabled.
+            if (this._compositionOptions.HasFlag(CompositionOptions.DisableSilentRejection))
+            {
+                return;
+            }
+
+            // NOTE : this is a very intricate area threading-wise, please use caution when changing, otherwise state corruption or deadlocks will ensue
+            // The gist of what we are doing is as follows:
+            // We need to lock the composition, as we will proceed modifying our internal state. The tricky part is when we release the lock
+            // Due to the fact that some actions will take place AFTER we leave this method, we need to KEEP THAT LOCK HELD until the transation is commiited or rolled back
+            // This is the reason we CAN'T use "using here.
+            // Instead, if the transaction is present we will queue up the release of the lock, otherwise we will release it when we exit this method
+            // We add the "release" lock to BOTH Commit and Revert queues, because they are mutually exclusive, and we need to release the lock regardless.
+
+            // This will take the lock, if necesary
+            IDisposable compositionLockHolder = this._lock.IsThreadSafe ? this._lock.LockComposition() : null;
+            bool compositionLockTaken = (compositionLockHolder != null);
+            try
+            {
+                // revert actions are processed in the reverse order, so we have to add the "release lock" action now
+                if (compositionLockTaken && (atomicComposition != null))
+                {
+                    atomicComposition.AddRevertAction(() => compositionLockHolder.Dispose());
+                }
+
+                var partManager = GetPartManager(part, true);
+                var result = TryPreviewImportsStateMachine(partManager, part, atomicComposition);
+                result.ThrowOnErrors(atomicComposition);
+                
+                StartSatisfyingImports(partManager, atomicComposition);
+
+                // Add the "release lock" to the commit actions
+                if (compositionLockTaken && (atomicComposition != null))
+                {
+                    atomicComposition.AddCompleteAction(() => compositionLockHolder.Dispose());
+                }
+            }
+            finally
+            {
+                // We haven't updated the queues, so we can release the lock now
+                if (compositionLockTaken && (atomicComposition == null))
+                {
+                    compositionLockHolder.Dispose();
+                }
+            }
+        }
+
+        /// <summary>
+        ///     Satisfies the imports of the specified composable part. If the satisfy succeeds then
+        ///     the <see cref="ImportEngine"/> also enforces that changes to exports in the source
+        ///     provider will not break any of the required imports. If this enforcement needs to be
+        ///     lifted for this part then <see cref="ReleaseImports"/> needs to be called for this
+        ///     <see cref="ComposablePart"/>.
+        /// </summary>
+        /// <param name="part">
+        ///     The <see cref="ComposablePart"/> to set the imports.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="part"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ImportEngine"/> has been disposed of.
+        /// </exception>
+        public void SatisfyImports(ComposablePart part)
+        {
+            this.ThrowIfDisposed();
+
+            Requires.NotNull(part, "part");
+
+            // NOTE : the following two calls use the state lock
+            PartManager partManager = this.GetPartManager(part, true);
+            if (partManager.State == ImportState.Composed)
+            {
+                return;
+            }
+
+            using (this._lock.LockComposition())
+            {
+                var result = TrySatisfyImports(partManager, part, true);
+                result.ThrowOnErrors(); // throw CompositionException not ChangeRejectedException
+            }
+        }
+
+        /// <summary>
+        ///     Sets the imports of the specified composable part exactly once and they will not
+        ///     ever be recomposed.
+        /// </summary>
+        /// <param name="part">
+        ///     The <see cref="ComposablePart"/> to set the imports.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="part"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ICompositionService"/> has been disposed of.
+        /// </exception>
+        public void SatisfyImportsOnce(ComposablePart part)
+        {
+            this.ThrowIfDisposed();
+
+            Requires.NotNull(part, "part");
+
+            // NOTE : the following two calls use the state lock
+            PartManager partManager = this.GetPartManager(part, true);
+            if (partManager.State == ImportState.Composed)
+            {
+                return;
+            }
+
+            using (this._lock.LockComposition())
+            {
+                var result = TrySatisfyImports(partManager, part, false);
+                result.ThrowOnErrors(); // throw CompositionException not ChangeRejectedException
+            }
+        }
+
+        /// <summary>
+        ///     Removes any state stored in the <see cref="ImportEngine"/> for the associated 
+        ///     <see cref="ComposablePart"/> and releases all the <see cref="Export"/>s used to 
+        ///     satisfy the imports on the <see cref="ComposablePart"/>.
+        ///     
+        ///     Also removes the enforcement for changes that would break a required import on
+        ///     <paramref name="part"/>.
+        /// </summary>
+        /// <param name="part">
+        ///     The <see cref="ComposablePart"/> to release the imports on. 
+        /// </param>
+        /// <param name="atomicComposition">
+        ///     The <see cref="AtomicComposition"/> that the release imports is running under.
+        /// </param>
+        public void ReleaseImports(ComposablePart part, AtomicComposition atomicComposition)
+        {
+            this.ThrowIfDisposed();
+
+            Requires.NotNull(part, "part");
+
+            using (this._lock.LockComposition())
+            {
+                PartManager partManager = this.GetPartManager(part, false);
+                if (partManager != null)
+                {
+                    this.StopSatisfyingImports(partManager, atomicComposition);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
+        /// </summary>
+        public void Dispose()
+        {
+            this.Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        /// <summary>
+        /// Releases unmanaged and - optionally - managed resources
+        /// </summary>
+        /// <param name="disposing"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
+        protected virtual void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                if (!this._isDisposed)
+                {
+                    bool disposeLock = false;
+                    ExportProvider sourceProviderToUnsubscribeFrom = null;
+                    using (this._lock.LockStateForWrite())
+                    {
+                        if (!this._isDisposed)
+                        {
+                            sourceProviderToUnsubscribeFrom = this._sourceProvider;
+                            this._sourceProvider = null;
+                            this._recompositionManager = null;
+                            this._partManagers = null;
+                            this._isDisposed = true;
+                            disposeLock = true;
+                        }
+                    }
+
+                    if (sourceProviderToUnsubscribeFrom != null)
+                    {
+                        sourceProviderToUnsubscribeFrom.ExportsChanging -= this.OnExportsChanging;
+                    }
+
+                    if (disposeLock)
+                    {
+                        this._lock.Dispose();
+                    }
+                }
+            }
+        }
+
+        private CompositionResult TryPreviewImportsStateMachine(PartManager partManager,
+            ComposablePart part, AtomicComposition atomicComposition)
+        {
+            var result = CompositionResult.SucceededResult;
+
+            if (partManager.State == ImportState.ImportsPreviewing)
+            {
+                // We shouldn't nomally ever hit this case but if we do 
+                // then we should just error with a cycle error.
+                return new CompositionResult(ErrorBuilder.CreatePartCycle(part));
+            }
+
+            // Transition from NoImportsStatisified to ImportsPreviewed
+            if (partManager.State == ImportState.NoImportsSatisfied)
+            {
+                partManager.State = ImportState.ImportsPreviewing;
+
+                var requiredImports = part.ImportDefinitions.Where(IsRequiredImportForPreview);
+
+                // If this atomicComposition gets rolledback for any reason we need to reset our state
+                atomicComposition.AddRevertActionAllowNull(() => partManager.State = ImportState.NoImportsSatisfied);
+
+                result = result.MergeResult(
+                    this.TrySatisfyImportSubset(partManager, requiredImports, atomicComposition));
+
+                if (!result.Succeeded)
+                {
+                    partManager.State = ImportState.NoImportsSatisfied;
+                    return result;
+                }
+
+                partManager.State = ImportState.ImportsPreviewed;
+            }
+
+            return result;
+        }
+
+        private CompositionResult TrySatisfyImportsStateMachine(PartManager partManager, ComposablePart part)
+        {
+            var result = CompositionResult.SucceededResult;
+
+            while (partManager.State < ImportState.Composed)
+            {
+                var previousState = partManager.State;
+
+                switch (partManager.State)
+                {
+                    // "ed" states which represent a some sort of steady state and will
+                    // attempt to do a state transition
+                    case ImportState.NoImportsSatisfied:
+                    case ImportState.ImportsPreviewed:
+                    {
+                        partManager.State = ImportState.PreExportImportsSatisfying;
+
+                        var prereqImports = part.ImportDefinitions.Where(import => import.IsPrerequisite);
+                        result = result.MergeResult(
+                            this.TrySatisfyImportSubset(partManager, prereqImports, null));
+
+                        partManager.State = ImportState.PreExportImportsSatisfied;
+                        break;
+                    }
+                    case ImportState.PreExportImportsSatisfied:
+                    {
+                        partManager.State = ImportState.PostExportImportsSatisfying;
+
+                        var requiredImports = part.ImportDefinitions.Where(import => !import.IsPrerequisite);
+                        
+                        result = result.MergeResult(
+                            this.TrySatisfyImportSubset(partManager, requiredImports, null));
+
+                        partManager.State = ImportState.PostExportImportsSatisfied;
+                        break;
+                    }
+                    case ImportState.PostExportImportsSatisfied:
+                    {
+                        partManager.State = ImportState.ComposedNotifying;
+
+                        partManager.ClearSavedImports();
+                        result = result.MergeResult(partManager.TryOnComposed());
+  
+                        partManager.State = ImportState.Composed;
+                        break;
+                    }
+ 
+
+                    // "ing" states which represent some sort of cycle
+                    // These state should always return, error or not, instead of breaking
+                    case ImportState.ImportsPreviewing:
+                    {
+                        // We shouldn't nomally ever hit this case but if we do 
+                        // then we should just error with a cycle error.
+                        return new CompositionResult(ErrorBuilder.CreatePartCycle(part));
+                    }
+                    case ImportState.PreExportImportsSatisfying:
+                    case ImportState.PostExportImportsSatisfying:
+                    {
+                        if (InPrerequisiteLoop())
+                        {
+                            return result.MergeError(ErrorBuilder.CreatePartCycle(part));
+                        }
+                        // Cycles in post export imports are allowed so just return in that case
+                        return result;
+                    }
+                    case ImportState.ComposedNotifying:
+                    {
+                        // We are currently notifying so don't notify again just return
+                        return result;
+                    }
+                }
+
+                // if an error occured while doing a state transition 
+                if (!result.Succeeded)
+                {
+                    // revert to the previous state and return the error
+                    partManager.State = previousState;
+                    return result;
+                }
+            }
+            return result;
+        }
+
+        private CompositionResult TrySatisfyImports(PartManager partManager, ComposablePart part, bool shouldTrackImports)
+        {
+            Assumes.NotNull(part);
+
+            var result = CompositionResult.SucceededResult;
+
+            // get out if the part is already composed
+            if (partManager.State == ImportState.Composed)
+            {
+                return result;
+            }
+
+            // Track number of recursive iterations and throw an exception before the stack
+            // fills up and debugging the root cause becomes tricky
+            if (this._recursionStateStack.Count >= MaximumNumberOfCompositionIterations)
+            {
+                return result.MergeError(
+                    ErrorBuilder.ComposeTookTooManyIterations(MaximumNumberOfCompositionIterations));
+            }
+
+            // Maintain the stack to detect whether recursive loops cross prerequisites
+            this._recursionStateStack.Push(partManager);
+            try
+            {
+                result = result.MergeResult(
+                    TrySatisfyImportsStateMachine(partManager, part));
+            }
+            finally
+            {
+                this._recursionStateStack.Pop();
+            }
+
+            if (shouldTrackImports)
+            {
+                StartSatisfyingImports(partManager, null);
+            }
+
+            return result;
+        }
+
+        private CompositionResult TrySatisfyImportSubset(PartManager partManager,
+            IEnumerable<ImportDefinition> imports, AtomicComposition atomicComposition)
+        {
+            CompositionResult result = CompositionResult.SucceededResult;
+
+            var part = partManager.Part;
+            foreach (ImportDefinition import in imports) 
+            {
+                var exports = partManager.GetSavedImport(import);
+
+                if (exports == null)
+                {
+                    CompositionResult<IEnumerable<Export>> exportsResult = TryGetExports(
+                        this._sourceProvider, part, import, atomicComposition);
+
+                    if (!exportsResult.Succeeded)
+                    {
+                        result = result.MergeResult(exportsResult.ToResult());
+                        continue;
+                    }
+                    exports = exportsResult.Value.AsArray();
+                }
+
+                if (atomicComposition == null)
+                {
+                    result = result.MergeResult(
+                        partManager.TrySetImport(import, exports));
+                }
+                else
+                {
+                    partManager.SetSavedImport(import, exports, atomicComposition);
+                }
+            }
+            return result;
+        }
+
+        private void OnExportsChanging(object sender, ExportsChangeEventArgs e)
+        {
+            CompositionResult result = CompositionResult.SucceededResult;
+
+            // Prepare for the recomposition effort by minimizing the amount of work we'll have to do later
+            AtomicComposition atomicComposition = e.AtomicComposition;
+
+            IEnumerable<PartManager> affectedParts = this._recompositionManager.GetAffectedParts(e.ChangedContractNames);
+
+            // When in a atomicComposition account for everything that isn't yet reflected in the
+            // index
+            if (atomicComposition != null)
+            {
+                EngineContext engineContext;
+                if (atomicComposition.TryGetValue(this, out engineContext))
+                {
+                    // always added the new part managers to see if they will also be 
+                    // affected by these changes
+                    affectedParts = affectedParts.ConcatAllowingNull(engineContext.GetAddedPartManagers())
+                        .Except(engineContext.GetRemovedPartManagers());
+                }
+            }
+
+            var changedExports = e.AddedExports.ConcatAllowingNull(e.RemovedExports);
+
+            foreach (var partManager in affectedParts)
+            {
+                result = result.MergeResult(this.TryRecomposeImports(partManager, changedExports, atomicComposition));
+            }
+
+            result.ThrowOnErrors(atomicComposition);
+        }
+
+        private CompositionResult TryRecomposeImports(PartManager partManager, 
+            IEnumerable<ExportDefinition> changedExports, AtomicComposition atomicComposition)
+        {
+            var result = CompositionResult.SucceededResult;
+
+            switch (partManager.State)
+            {
+                case ImportState.ImportsPreviewed:
+                case ImportState.Composed:
+                    // Validate states to continue.
+                    break;
+
+                default:
+                {
+                    // All other states are invalid and for recomposition. 
+                    return new CompositionResult(ErrorBuilder.InvalidStateForRecompposition(partManager.Part));
+                }
+            }
+
+            var affectedImports = RecompositionManager.GetAffectedImports(partManager.Part, changedExports);
+            bool partComposed = (partManager.State == ImportState.Composed);
+
+            bool recomposedImport = false;
+            foreach (var import in affectedImports)
+            {
+                result = result.MergeResult(
+                    TryRecomposeImport(partManager, partComposed, import, atomicComposition));
+
+                recomposedImport = true;
+            }
+
+            // Knowing that the part has already been composed before and that the only possible
+            // changes are to recomposable imports, we can safely go ahead and do this now or
+            // schedule it for later
+            if (result.Succeeded && recomposedImport && partComposed)
+            {
+                if (atomicComposition == null)
+                {
+                    result = result.MergeResult(partManager.TryOnComposed());
+                }
+                else
+                {
+                    atomicComposition.AddCompleteAction(() => partManager.TryOnComposed().ThrowOnErrors());
+                }
+            }
+
+            return result;
+        }
+
+        private CompositionResult TryRecomposeImport(PartManager partManager, bool partComposed,
+            ImportDefinition import, AtomicComposition atomicComposition)
+        {
+            if (partComposed && !import.IsRecomposable)
+            {
+                return new CompositionResult(ErrorBuilder.PreventedByExistingImport(partManager.Part, import));
+            }
+
+            // During recomposition you must always requery with the new atomicComposition you cannot use any
+            // cached value in the part manager
+            var exportsResult = TryGetExports(this._sourceProvider, partManager.Part, import, atomicComposition);
+            if (!exportsResult.Succeeded)
+            {
+                return exportsResult.ToResult();
+            }
+            var exports = exportsResult.Value.AsArray();
+
+            if (partComposed)
+            {
+                // Knowing that the part has already been composed before and that the only possible
+                // changes are to recomposable imports, we can safely go ahead and do this now or
+                // schedule it for later
+                if (atomicComposition == null)
+                {
+                    return partManager.TrySetImport(import, exports);
+                }
+                else
+                {
+                    atomicComposition.AddCompleteAction(() => partManager.TrySetImport(import, exports).ThrowOnErrors());
+                }
+            }
+            else
+            {
+                partManager.SetSavedImport(import, exports, atomicComposition);
+            }
+
+            return CompositionResult.SucceededResult;
+        }
+
+        private void StartSatisfyingImports(PartManager partManager, AtomicComposition atomicComposition)
+        {
+            // When not running in a atomicCompositional state, schedule reindexing after ensuring
+            // that this isn't a redundant addition
+            if (atomicComposition == null)
+            {
+                if (!partManager.TrackingImports)
+                {
+                    partManager.TrackingImports = true;
+                    this._recompositionManager.AddPartToIndex(partManager);
+                }
+            }
+            else
+            {
+                // While in a atomicCompositional state use a less efficient but effective means
+                // of achieving the same results
+                GetEngineContext(atomicComposition).AddPartManager(partManager);
+            }
+        }
+
+        private void StopSatisfyingImports(PartManager partManager, AtomicComposition atomicComposition)
+        {
+            // When not running in a atomicCompositional state, schedule reindexing after ensuring
+            // that this isn't a redundant removal
+            if (atomicComposition == null)
+            {
+                this._partManagers.Remove(partManager.Part);
+
+                // Take care of lifetime requirements
+                partManager.DisposeAllDependencies();
+
+                if (partManager.TrackingImports)
+                {
+                    partManager.TrackingImports = false;
+                    this._recompositionManager.AddPartToUnindex(partManager);
+                }
+            }
+            else
+            {
+                // While in a atomicCompositional state use a less efficient but effective means
+                // of achieving the same results
+                GetEngineContext(atomicComposition).RemovePartManager(partManager);
+            }
+        }
+
+        private PartManager GetPartManager(ComposablePart part, bool createIfNotpresent)
+        {
+            PartManager partManager = null;
+            using (this._lock.LockStateForRead())
+            {
+                if (this._partManagers.TryGetValue(part, out partManager))
+                {
+                    return partManager;
+                }
+            }
+
+            if (createIfNotpresent)
+            {
+                using (this._lock.LockStateForWrite())
+                {
+                    if (!this._partManagers.TryGetValue(part, out partManager))
+                    {
+                        partManager = new PartManager(this, part);
+                        this._partManagers.Add(part, partManager);
+                    }
+                }
+            }
+            return partManager;
+        }
+
+
+        private EngineContext GetEngineContext(AtomicComposition atomicComposition)
+        {
+            Assumes.NotNull(atomicComposition);
+
+            EngineContext engineContext;
+            if (!atomicComposition.TryGetValue(this, true, out engineContext))
+            {
+                EngineContext parentContext;
+                atomicComposition.TryGetValue(this, false, out parentContext);
+                engineContext = new EngineContext(this, parentContext);
+                atomicComposition.SetValue(this, engineContext);
+                atomicComposition.AddCompleteAction(engineContext.Complete);
+            }
+            return engineContext;
+        }
+
+        private bool InPrerequisiteLoop()
+        {
+            PartManager firstPart = this._recursionStateStack.First();
+            PartManager lastPart = null;
+
+            foreach (PartManager testPart in this._recursionStateStack.Skip(1))
+            {
+                if (testPart.State == ImportState.PreExportImportsSatisfying)
+                {
+                    return true;
+                }
+
+                if (testPart == firstPart)
+                {
+                    lastPart = testPart;
+                    break;
+                }
+            }
+
+            // This should only be called when a loop has been detected - so it should always be on the stack
+            Assumes.IsTrue(lastPart == firstPart);
+            return false;
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+
+        private static CompositionResult<IEnumerable<Export>> TryGetExports(ExportProvider provider,
+            ComposablePart part, ImportDefinition definition, AtomicComposition atomicComposition)
+        {
+            try
+            {
+                var exports = provider.GetExports(definition, atomicComposition).AsArray();
+                return new CompositionResult<IEnumerable<Export>>(exports);
+            }
+            catch (ImportCardinalityMismatchException ex)
+            {
+                // Either not enough or too many exports that match the definition
+                CompositionException exception = new CompositionException(ErrorBuilder.CreateImportCardinalityMismatch(ex, definition));
+
+                return new CompositionResult<IEnumerable<Export>>(
+                    ErrorBuilder.CreatePartCannotSetImport(part, definition, exception));
+            }
+        }
+
+        internal static bool IsRequiredImportForPreview(ImportDefinition import)
+        {
+            return import.Cardinality == ImportCardinality.ExactlyOne;
+        }
+
+        // Ordering of this enum is important so be sure to use caution if you
+        // try to reorder them.
+        private enum ImportState
+        {
+            NoImportsSatisfied          = 0,
+            ImportsPreviewing           = 1,
+            ImportsPreviewed            = 2,
+            PreExportImportsSatisfying  = 3,
+            PreExportImportsSatisfied   = 4,
+            PostExportImportsSatisfying = 5,
+            PostExportImportsSatisfied  = 6,
+            ComposedNotifying           = 7,
+            Composed                    = 8,
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportSourceImportDefinitionHelpers.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportSourceImportDefinitionHelpers.cs
new file mode 100644
index 00000000000..d00a3eee547
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ImportSourceImportDefinitionHelpers.cs
@@ -0,0 +1,118 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Linq.Expressions;
+using Microsoft.Internal;
+using System.Diagnostics.Contracts;
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+
+    internal static class ImportSourceImportDefinitionHelpers
+    {
+        public static ImportDefinition RemoveImportSource(this ImportDefinition definition)
+        {
+            var contractBasedDefinition = definition as ContractBasedImportDefinition;
+            if(contractBasedDefinition == null)
+            {
+                return definition;
+            }
+            else
+            {
+                return new NonImportSourceImportDefinition(contractBasedDefinition);
+            }
+        }
+
+        internal class NonImportSourceImportDefinition : ContractBasedImportDefinition
+        {
+            private ContractBasedImportDefinition _sourceDefinition;
+            private IDictionary<string, object> _metadata;
+
+            public NonImportSourceImportDefinition(ContractBasedImportDefinition sourceDefinition)
+            {
+                Assumes.NotNull(sourceDefinition);
+                this._sourceDefinition = sourceDefinition;
+                this._metadata = null;
+            }
+
+            public override string ContractName
+            {
+                get { return this._sourceDefinition.ContractName; }
+            }
+
+            public override IDictionary<string, object> Metadata
+            {
+                get
+                {
+                    Contract.Ensures(Contract.Result<IDictionary<string, object>>() != null);
+
+                    var reply = this._metadata;
+                    if(reply == null)
+                    {
+                        reply = new Dictionary<string, object> (this._sourceDefinition.Metadata);
+                        reply.Remove(CompositionConstants.ImportSourceMetadataName);
+                        this._metadata = reply;
+                    }
+
+                    return reply;
+                }
+            }
+
+            public override ImportCardinality Cardinality
+            {
+                get { return this._sourceDefinition.Cardinality; }
+            }
+
+            public override Expression<Func<ExportDefinition, bool>> Constraint
+            {
+                get { return this._sourceDefinition.Constraint; }
+            }
+
+            public override bool IsPrerequisite
+            {
+                get { return this._sourceDefinition.IsPrerequisite; }
+            }
+
+            public override bool IsRecomposable
+            {
+                get { return this._sourceDefinition.IsRecomposable; }
+            }
+
+            public override bool IsConstraintSatisfiedBy(ExportDefinition exportDefinition)
+            {
+                Requires.NotNull(exportDefinition, "exportDefinition");
+
+                return this._sourceDefinition.IsConstraintSatisfiedBy(exportDefinition);
+            }
+
+            public override string ToString()
+            {
+                return this._sourceDefinition.ToString();
+            }
+
+            public override string RequiredTypeIdentity
+            {
+                get { return this._sourceDefinition.RequiredTypeIdentity; }
+            }
+
+            public override IEnumerable<KeyValuePair<string, Type>> RequiredMetadata
+            {
+                get
+                {
+                    return this._sourceDefinition.RequiredMetadata;
+                }
+            }
+
+            public override CreationPolicy RequiredCreationPolicy
+            {
+                get { return this._sourceDefinition.RequiredCreationPolicy; }
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ScopingExtensions.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ScopingExtensions.cs
new file mode 100644
index 00000000000..f0d0e558773
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/ScopingExtensions.cs
@@ -0,0 +1,148 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Diagnostics;
+using System.Collections.Generic;
+using Microsoft.Internal;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    public static class ScopingExtensions
+    {
+        /// <summary>
+        /// Determines whether the specified part exports the specified contract.
+        /// </summary>
+        /// <param name="part">The part.</param>
+        /// <param name="contractName">Name of the contract.</param>
+        /// <returns>
+        /// 	<c>true</c> if the specified part exports the specified contract; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool Exports(this ComposablePartDefinition part, string contractName)
+        {
+            Requires.NotNull(part, "part");
+            Requires.NotNull(contractName, "contractName");
+
+            foreach (ExportDefinition export in part.ExportDefinitions)
+            {
+                if (StringComparers.ContractName.Equals(contractName, export.ContractName))
+                {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        /// <summary>
+        /// Determines whether the specified part imports the specified contract.
+        /// </summary>
+        /// <param name="part">The part.</param>
+        /// <param name="contractName">Name of the contract.</param>
+        /// <returns>
+        /// 	<c>true</c> if the specified part imports the specified contract; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool Imports(this ComposablePartDefinition part, string contractName)
+        {
+            Requires.NotNull(part, "part");
+            Requires.NotNull(contractName, "contractName");
+
+            foreach (ImportDefinition import in part.ImportDefinitions)
+            {
+                if (StringComparers.ContractName.Equals(contractName, import.ContractName))
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Determines whether the specified part imports the specified contract with the given cardinality.
+        /// </summary>
+        /// <param name="part">The part.</param>
+        /// <param name="contractName">Name of the contract.</param>
+        /// <param name="importCardinality">The import cardinality.</param>
+        /// <returns>
+        /// 	<c>true</c> if the specified part imports the specified contract with the given cardinality; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool Imports(this ComposablePartDefinition part, string contractName, ImportCardinality importCardinality)
+        {
+            Requires.NotNull(part, "part");
+            Requires.NotNull(contractName, "contractName");
+
+            foreach (ImportDefinition import in part.ImportDefinitions)
+            {
+                if (StringComparers.ContractName.Equals(contractName, import.ContractName) && (import.Cardinality == importCardinality))
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+
+        /// <summary>
+        /// Determines whether the part contains a metadata entry with the specified key.
+        /// </summary>
+        /// <param name="part">The part.</param>
+        /// <param name="key">The key.</param>
+        /// <returns>
+        /// 	<c>true</c> if the part contains a metadata entry with the specified key; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool ContainsPartMetadataWithKey(this ComposablePartDefinition part, string key)
+        {
+            Requires.NotNull(part, "part");
+            Requires.NotNull(key, "key");
+
+            return part.Metadata.ContainsKey(key);
+        }
+
+        /// <summary>
+        /// Determines whether the specified part contains a metadata entry with the specified key and value.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="part">The part.</param>
+        /// <param name="key">The key.</param>
+        /// <param name="value">The value.</param>
+        /// <returns>
+        /// 	<c>true</c> the specified part contains a metadata entry with the specified key and value; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool ContainsPartMetadata<T>(this ComposablePartDefinition part, string key, T value)
+        {
+            Requires.NotNull(part, "part");
+            Requires.NotNull(key, "key");
+
+            object untypedValue = null;
+            if (part.Metadata.TryGetValue(key, out untypedValue))
+            {
+                if (value == null)
+                {
+                    return (untypedValue == null);
+                }
+                else
+                {
+                    return value.Equals(untypedValue);
+                }
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Filters the specified catalog.
+        /// </summary>
+        /// <param name="catalog">The catalog.</param>
+        /// <param name="filter">The filter.</param>
+        /// <returns></returns>
+        public static FilteredCatalog Filter(this ComposablePartCatalog catalog, Func<ComposablePartDefinition, bool> filter)
+        {
+            Requires.NotNull(catalog, "catalog");
+            Requires.NotNull(filter, "filter");
+
+            return new FilteredCatalog(catalog, filter);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/TypeCatalog.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/TypeCatalog.cs
new file mode 100644
index 00000000000..1bc94232b93
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Hosting/TypeCatalog.cs
@@ -0,0 +1,415 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.AttributedModel;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Globalization;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using System.Threading;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Hosting
+{
+    /// <summary>
+    ///     An immutable ComposablePartCatalog created from a type array or a list of managed types.  This class is threadsafe.
+    ///     It is Disposable.
+    /// </summary>
+    [DebuggerTypeProxy(typeof(ComposablePartCatalogDebuggerProxy))]
+    public class TypeCatalog : ComposablePartCatalog, ICompositionElement
+    {
+        private readonly object _thisLock = new object();
+        private Type[] _types = null;
+        private volatile List<ComposablePartDefinition> _parts;
+        private volatile bool _isDisposed = false;
+        private readonly ICompositionElement _definitionOrigin;
+        private readonly Lazy<IDictionary<string, List<ComposablePartDefinition>>> _contractPartIndex;
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="TypeCatalog"/> class 
+        ///     with the specified types.
+        /// </summary>
+        /// <param name="types">
+        ///     An <see cref="Array"/> of attributed <see cref="Type"/> objects to add to the 
+        ///     <see cref="TypeCatalog"/>.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="types"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="types"/> contains an element that is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="types"/> contains an element that was loaded in the Reflection-only context.
+        /// </exception>
+        public TypeCatalog(params Type[] types) : this((IEnumerable<Type>)types)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="TypeCatalog"/> class
+        ///     with the specified types.
+        /// </summary>
+        /// <param name="types">
+        ///     An <see cref="IEnumerable{T}"/> of attributed <see cref="Type"/> objects to add 
+        ///     to the <see cref="TypeCatalog"/>.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="types"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="types"/> contains an element that is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="types"/> contains an element that was loaded in the reflection-only context.
+        /// </exception>
+        public TypeCatalog(IEnumerable<Type> types)
+        {
+            Requires.NotNull(types, "types");
+
+            InitializeTypeCatalog(types);
+
+            this._definitionOrigin = this;
+            this._contractPartIndex = new Lazy<IDictionary<string, List<ComposablePartDefinition>>>(this.CreateIndex, true);
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="TypeCatalog"/> class
+        ///     with the specified types.
+        /// </summary>
+        /// <param name="types">
+        ///     An <see cref="IEnumerable{T}"/> of attributed <see cref="Type"/> objects to add 
+        ///     to the <see cref="TypeCatalog"/>.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="types"/> is <see langword="null"/>.
+        /// </exception>
+        /// <param name="definitionOrigin">
+        ///     The <see cref="ICompositionElement"/> CompositionElement used by Diagnostics to identify the source for parts.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="types"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        public TypeCatalog(IEnumerable<Type> types, ICompositionElement definitionOrigin)
+        {
+            Requires.NotNull(types, "types");
+            Requires.NotNull(definitionOrigin, "definitionOrigin");
+
+            InitializeTypeCatalog(types);
+
+            this._definitionOrigin = definitionOrigin;
+            this._contractPartIndex = new Lazy<IDictionary<string, List<ComposablePartDefinition>>>(this.CreateIndex, true);
+        }
+
+#if FEATURE_REFLECTIONCONTEXT
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="TypeCatalog"/> class
+        ///     with the specified types.
+        /// </summary>
+        /// <param name="types">
+        ///     An <see cref="IEnumerable{T}"/> of attributed <see cref="Type"/> objects to add 
+        ///     to the <see cref="TypeCatalog"/>.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="types"/> is <see langword="null"/>.
+        /// </exception>
+        /// <param name="reflectionContext">
+        ///     The <see cref="ReflectionContext"/> a context used by the catalog when 
+        ///     interpreting the types to inject attributes into the type definition.
+        /// </param>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="types"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        public TypeCatalog(IEnumerable<Type> types, ReflectionContext reflectionContext)
+        {
+            Requires.NotNull(types, "types");
+            Requires.NotNull(reflectionContext, "reflectionContext");
+
+            InitializeTypeCatalog(types, reflectionContext);
+
+            this._definitionOrigin = this;
+            this._contractPartIndex = new Lazy<IDictionary<string, List<ComposablePartDefinition>>>(this.CreateIndex, true);
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="TypeCatalog"/> class
+        ///     with the specified types.
+        /// </summary>
+        /// <param name="types">
+        ///     An <see cref="IEnumerable{T}"/> of attributed <see cref="Type"/> objects to add 
+        ///     to the <see cref="TypeCatalog"/>.
+        /// </param>
+        /// <param name="reflectionContext">
+        ///     The <see cref="ReflectionContext"/> a context used by the catalog when 
+        ///     interpreting the types to inject attributes into the type definition.
+        /// </param>
+        /// <param name="definitionOrigin">
+        ///     The <see cref="ICompositionElement"/> CompositionElement used by Diagnostics to identify the source for parts.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="types"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="types"/> contains an element that is <see langword="null"/>.
+        /// </exception>
+        public TypeCatalog(IEnumerable<Type> types, ReflectionContext reflectionContext, ICompositionElement definitionOrigin)
+        {
+            Requires.NotNull(types, "types");
+            Requires.NotNull(reflectionContext, "reflectionContext");
+            Requires.NotNull(definitionOrigin, "definitionOrigin");
+
+            InitializeTypeCatalog(types, reflectionContext);
+
+            this._definitionOrigin = definitionOrigin;
+            this._contractPartIndex = new Lazy<IDictionary<string, List<ComposablePartDefinition>>>(this.CreateIndex, true);
+        }
+
+        private void InitializeTypeCatalog(IEnumerable<Type> types, ReflectionContext reflectionContext)
+        {
+            var typesList = new List<Type>();
+            foreach(var type in types)
+            {
+                if (type == null)
+                {
+                    throw ExceptionBuilder.CreateContainsNullElement("types");
+                }
+
+                if (type.Assembly.ReflectionOnly)
+                {
+                    throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, Strings.Argument_ElementReflectionOnlyType, "types"), "types");
+                }
+
+                var typeInfo = type.GetTypeInfo();
+                var lclType = (reflectionContext != null) ? reflectionContext.MapType(typeInfo) : typeInfo;
+                
+                // It is valid for the reflectionContext to delete types by mapping them to null
+                if(lclType != null)
+                {
+                    // The final mapped type may be activated so we check to see if it is in a reflect only assembly
+                    if (lclType.Assembly.ReflectionOnly)
+                    {
+                        throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, Strings.Argument_ReflectionContextReturnsReflectionOnlyType, "reflectionContext"), "reflectionContext");
+                    }
+
+
+                    typesList.Add(lclType);
+                }
+            }
+            this._types = typesList.ToArray();
+        }
+#endif //FEATURE_REFLECTIONCONTEXT
+
+        private void InitializeTypeCatalog(IEnumerable<Type> types)
+        {
+            foreach(var type in types)
+            {
+                if (type == null)
+                {
+                    throw ExceptionBuilder.CreateContainsNullElement("types");
+                }
+#if FEATURE_REFLECTIONONLY
+                else if (type.Assembly.ReflectionOnly)
+                {
+                    throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, Strings.Argument_ElementReflectionOnlyType, "types"), "types");
+                }
+#endif //FEATURE_REFLECTIONONLY
+            }
+            this._types = types.ToArray();
+        }
+
+
+        public override IEnumerator<ComposablePartDefinition> GetEnumerator()
+        {
+            this.ThrowIfDisposed();
+            return this.PartsInternal.GetEnumerator();
+        }
+
+        /// <summary>
+        ///     Gets the display name of the type catalog.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="String"/> containing a human-readable display name of the <see cref="TypeCatalog"/>.
+        /// </value>
+        [SuppressMessage("Microsoft.Design", "CA1033:InterfaceMethodsShouldBeCallableByChildTypes")]
+        string ICompositionElement.DisplayName
+        {
+            get { return this.GetDisplayName(); }
+        }
+
+        /// <summary>
+        ///     Gets the composition element from which the type catalog originated.
+        /// </summary>
+        /// <value>
+        ///     This property always returns <see langword="null"/>.
+        /// </value>
+        [SuppressMessage("Microsoft.Design", "CA1033:InterfaceMethodsShouldBeCallableByChildTypes")]
+        ICompositionElement ICompositionElement.Origin
+        {
+            get { return null; }
+        }
+
+        private IEnumerable<ComposablePartDefinition> PartsInternal
+        {
+            get
+            {
+                if (this._parts == null)
+                {
+                    lock (this._thisLock)
+                    {
+                        if (this._parts == null)
+                        {
+                            Assumes.NotNull(this._types);
+
+                            var collection = new List<ComposablePartDefinition>();
+                            foreach (Type type in this._types)
+                            {
+                                var definition = AttributedModelDiscovery.CreatePartDefinitionIfDiscoverable(type, _definitionOrigin);
+                                if (definition != null)
+                                {
+                                    collection.Add(definition);
+                                }
+                            }
+                            Thread.MemoryBarrier();
+
+                            this._types = null;
+                            this._parts = collection;
+                        }
+                    }
+                }
+
+                return this._parts;
+            }
+        }
+
+        internal override IEnumerable<ComposablePartDefinition> GetCandidateParts(ImportDefinition definition)
+        {
+            Assumes.NotNull(definition);
+
+            string contractName = definition.ContractName;
+            if (string.IsNullOrEmpty(contractName))
+            {
+                return this.PartsInternal;
+            }
+
+            string genericContractName = definition.Metadata.GetValue<string>(CompositionConstants.GenericContractMetadataName);
+
+            List<ComposablePartDefinition> nonGenericMatches = this.GetCandidateParts(contractName);
+            List<ComposablePartDefinition> genericMatches = this.GetCandidateParts(genericContractName);
+
+            return nonGenericMatches.ConcatAllowingNull(genericMatches);
+        }
+
+        private List<ComposablePartDefinition> GetCandidateParts(string contractName)
+        {
+            if (contractName == null)
+            {
+                return null;
+            }
+
+            List<ComposablePartDefinition> contractCandidateParts = null;
+            this._contractPartIndex.Value.TryGetValue(contractName, out contractCandidateParts);
+            return contractCandidateParts;
+        }
+
+        private IDictionary<string, List<ComposablePartDefinition>> CreateIndex()
+        {
+            Dictionary<string, List<ComposablePartDefinition>> index = new Dictionary<string, List<ComposablePartDefinition>>(StringComparers.ContractName);
+
+            foreach (var part in this.PartsInternal)
+            {
+                foreach (string contractName in part.ExportDefinitions.Select(export => export.ContractName).Distinct())
+                {
+                    List<ComposablePartDefinition> contractParts = null;
+                    if (!index.TryGetValue(contractName, out contractParts))
+                    {
+                        contractParts = new List<ComposablePartDefinition>();
+                        index.Add(contractName, contractParts);
+                    }
+                    contractParts.Add(part);
+                }
+            }
+            return index;
+        }
+
+        /// <summary>
+        ///     Returns a string representation of the type catalog.
+        /// </summary>
+        /// <returns>
+        ///     A <see cref="String"/> containing the string representation of the <see cref="TypeCatalog"/>.
+        /// </returns>
+        public override string ToString()
+        {
+            return this.GetDisplayName();
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                this._isDisposed = true;
+            }
+
+            base.Dispose(disposing);
+        }
+
+        private string GetDisplayName()
+        {
+            return String.Format(CultureInfo.CurrentCulture,
+                                Strings.TypeCatalog_DisplayNameFormat,
+                                this.GetType().Name,
+                                this.GetTypesDisplay());
+        }
+
+        private string GetTypesDisplay()
+        {
+            int count = this.PartsInternal.Count();
+            if (count == 0)
+            {
+                return Strings.TypeCatalog_Empty;
+            }
+
+            const int displayCount = 2;
+            StringBuilder builder = new StringBuilder();
+            foreach (ReflectionComposablePartDefinition definition in this.PartsInternal.Take(displayCount))
+            {
+                if (builder.Length > 0)
+                {
+                    builder.Append(CultureInfo.CurrentCulture.TextInfo.ListSeparator);
+                    builder.Append(" ");
+                }
+
+                builder.Append(definition.GetPartType().GetDisplayName());
+            }
+
+            if (count > displayCount)
+            {   // Add an elipse to indicate that there 
+                // are more types than actually listed
+                builder.Append(CultureInfo.CurrentCulture.TextInfo.ListSeparator);
+                builder.Append(" ...");
+            }
+
+            return builder.ToString();
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/IAttributedImport.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/IAttributedImport.cs
new file mode 100644
index 00000000000..39158c7fdab
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/IAttributedImport.cs
@@ -0,0 +1,18 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition
+{
+    internal interface IAttributedImport
+    {
+        string ContractName { get; }
+        Type ContractType { get; }
+        bool AllowRecomposition { get; }
+        CreationPolicy RequiredCreationPolicy { get; }
+        ImportCardinality Cardinality { get; }
+        ImportSource Source { get; }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ICompositionService.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ICompositionService.cs
new file mode 100644
index 00000000000..fac6448e957
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ICompositionService.cs
@@ -0,0 +1,38 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.Contracts;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Provides methods for composing <see cref="ComposablePart"/> objects.
+    /// </summary>
+#if CONTRACTS_FULL
+    [ContractClass(typeof(ICompositionServiceContract))]
+#endif
+    public interface ICompositionService
+    {
+        /// <summary>
+        ///     Sets the imports of the specified composable part exactly once and they will not
+        ///     ever be recomposed.
+        /// </summary>
+        /// <param name="part">
+        ///     The <see cref="ComposablePart"/> to set the imports.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="part"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ICompositionService"/> has been disposed of.
+        /// </exception>
+        void SatisfyImportsOnce(ComposablePart part);
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/IPartImportsSatisfiedNotification.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/IPartImportsSatisfiedNotification.cs
new file mode 100644
index 00000000000..7969e0cb7cf
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/IPartImportsSatisfiedNotification.cs
@@ -0,0 +1,12 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+
+namespace System.ComponentModel.Composition
+{
+    public interface IPartImportsSatisfiedNotification
+    {
+        void OnImportsSatisfied();
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportAttribute.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportAttribute.cs
new file mode 100644
index 00000000000..48f2aea8fc5
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportAttribute.cs
@@ -0,0 +1,197 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Specifies that a property, field, or parameter imports a particular export.
+    /// </summary>
+    [SuppressMessage("Microsoft.Performance", "CA1813:AvoidUnsealedAttributes")]
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter,
+                    AllowMultiple = false, Inherited = false)]
+    public class ImportAttribute : Attribute, IAttributedImport
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportAttribute"/> class, importing the 
+        ///     export with the default contract name.
+        /// </summary>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the property, field, 
+        ///         or parameter type that this is marked with this attribute.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public ImportAttribute()
+            : this((string)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportAttribute"/> class, importing the
+        ///     export with the contract name derived from the specified type.
+        /// </summary>
+        /// <param name="contractType">
+        ///     A <see cref="Type"/> of which to derive the contract name of the export to import, or 
+        ///     <see langword="null"/> to use the default contract name.
+        /// </param>
+        /// <remarks>
+        ///     <para>
+        ///         The contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on 
+        ///         <paramref name="contractType"/>.
+        ///     </para>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the property, field, 
+        ///         or parameter type that is marked with this attribute.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public ImportAttribute(Type contractType) 
+            : this((string)null, contractType)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportAttribute"/> class, importing the
+        ///     export with the specified contract name.
+        /// </summary>
+        /// <param name="contractName">
+        ///      A <see cref="String"/> containing the contract name of the export to import, or 
+        ///      <see langword="null"/> or an empty string ("") to use the default contract name.
+        /// </param>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the property, field, 
+        ///         or parameter type that is marked with this attribute.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public ImportAttribute(string contractName)
+            : this(contractName, (Type)null)
+        {
+        }
+
+        public ImportAttribute(string contractName, Type contractType)
+        {
+            this.ContractName = contractName;
+            this.ContractType = contractType;
+        }
+
+        /// <summary>
+        ///     Gets the contract name of the export to import.
+        /// </summary>
+        /// <value>
+        ///      A <see cref="String"/> containing the contract name of the export to import. The 
+        ///      default value is an empty string ("").
+        /// </value>
+        public string ContractName { get; private set; }
+
+        /// <summary>
+        ///     Get the contract type of the export to import.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="Type"/> of the export that this import is expecting. The default value is
+        ///     <see langword="null"/> which means that the type will be obtained by looking at the type on
+        ///     the member that this import is attached to. If the type is <see cref="object"/> then the
+        ///     importer is delaring they can accept any exported type.
+        /// </value>
+        public Type ContractType { get; private set; }
+
+        /// <summary>
+        ///     Gets or sets a value indicating whether the property, field or parameter will be set 
+        ///     to its type's default value when an export with the contract name is not present in 
+        ///     the container.
+        /// </summary>
+        /// <value>
+        ///     <see langword="true"/> if the property, field or parameter will be set 
+        ///     its type's default value when an export with the <see cref="ContractName"/> is not 
+        ///     present in the <see cref="CompositionContainer"/>; otherwise, <see langword="false"/>. 
+        ///     The default value is <see langword="false"/>.
+        /// </value>
+        /// <remarks>
+        ///     <para>
+        ///         The default value of a property's, field's or parameter's type is 
+        ///         <see langword="null"/> for reference types and 0 for numeric value types. For 
+        ///         other value types, the default value will be each field of the value type 
+        ///         initialized to zero, if the field is a value type or <see langword="null"/> if 
+        ///         the field is a reference type.
+        ///     </para>
+        /// </remarks>
+        public bool AllowDefault { get; set; }
+
+        /// <summary>
+        ///     Gets or sets a value indicating whether the property or field will be recomposed
+        ///     when exports that provide the same contract that this import expects, have changed
+        ///     in the container. 
+        /// </summary>
+        /// <value>
+        ///     <see langword="true"/> if the property or field allows for recomposition when exports
+        ///     that provide the same <see cref="ContractName"/> are added or removed from the 
+        ///     <see cref="CompositionContainer"/>; otherwise, <see langword="false"/>. 
+        ///     The default value is <see langword="false"/>.
+        /// </value>
+        public bool AllowRecomposition { get; set; }
+
+        /// <summary>
+        ///     Gets or sets a value indicating that the importer requires a specific 
+        ///     <see cref="CreationPolicy"/> for the exports used to satisfy this import. T
+        /// </summary>
+        /// <value>
+        ///     <see cref="CreationPolicy.Any"/> - default value, used if the importer doesn't 
+        ///         require a specific <see cref="CreationPolicy"/>.
+        /// 
+        ///     <see cref="CreationPolicy.Shared"/> - Requires that all exports used should be shared
+        ///         by everyone in the container.
+        /// 
+        ///     <see cref="CreationPolicy.NonShared"/> - Requires that all exports used should be 
+        ///         non-shared in a container and thus everyone gets their own instance.
+        /// </value>
+        public CreationPolicy RequiredCreationPolicy { get; set; }
+
+        /// <summary>
+        ///     Gets or sets a value indicating that the importer indicating that the composition engine 
+        ///     either should satisfy exports from the local or no local scope.
+        /// </summary>
+        /// <value>
+        ///     <see cref="ImportSource.Any"/> - indicates that importer does not
+        ///         require a specific satisfaction scope"/>.
+        /// 
+        ///     <see cref="ImportSource.Local"/> - indicates the importer requires satisfaction to be
+        ///         from the current container.
+        /// 
+        ///     <see cref="ImportSource.NonLocal"/> - indicates the importer requires satisfaction to be
+        ///         from one of the ancestor containers.
+        /// </value>
+        public ImportSource Source { get; set; }
+
+        ImportCardinality IAttributedImport.Cardinality
+        {
+            get
+            {
+                if (this.AllowDefault == true)
+                {
+                    return ImportCardinality.ZeroOrOne;
+                }
+                return ImportCardinality.ExactlyOne;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportCardinalityMismatchException.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportCardinalityMismatchException.cs
new file mode 100644
index 00000000000..c3f293ac6d4
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportCardinalityMismatchException.cs
@@ -0,0 +1,94 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Runtime.Serialization;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     The exception that is thrown when the cardinality of a <see cref="ImportDefinition"/>
+    ///     does not match the cardinality of the <see cref="Export"/> objects available in an 
+    ///     <see cref="ExportProvider"/>.
+    /// </summary>
+    [Serializable]
+    [DebuggerTypeProxy(typeof(ImportCardinalityMismatchExceptionDebuggerProxy))]
+    [DebuggerDisplay("{Message}")]
+    public class ImportCardinalityMismatchException : Exception
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportCardinalityMismatchException"/> class.
+        /// </summary>
+        public ImportCardinalityMismatchException()
+            : this((string)null, (Exception)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportCardinalityMismatchException"/> class 
+        ///     with the specified error message.
+        /// </summary>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="ImportCardinalityMismatchException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.Message"/> property to its default value.
+        /// </param>
+        public ImportCardinalityMismatchException(string message)
+            : this(message, (Exception)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportCardinalityMismatchException"/> class 
+        ///     with the specified error message and exception that is the cause of the  
+        ///     exception.
+        /// </summary>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="ImportCardinalityMismatchException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.Message"/> property to its default value.
+        /// </param>
+        /// <param name="innerException">
+        ///     The <see cref="Exception"/> that is the underlying cause of the 
+        ///     <see cref="ImportCardinalityMismatchException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.InnerException"/> property to <see langword="null"/>.
+        /// </param>
+        public ImportCardinalityMismatchException(string message, Exception innerException)
+            : base(message, innerException)
+        {
+        }
+
+#if FEATURE_SERIALIZATION
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportCardinalityMismatchException"/> class 
+        ///     with the specified serialization data.
+        /// </summary>
+        /// <param name="info">
+        ///     The <see cref="SerializationInfo"/> that holds the serialized object data about the 
+        ///     <see cref="ImportCardinalityMismatchException"/>.
+        /// </param>
+        /// <param name="context">
+        ///     The <see cref="StreamingContext"/> that contains contextual information about the 
+        ///     source or destination.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="info"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="SerializationException">
+        ///     <paramref name="info"/> is missing a required value.
+        /// </exception>
+        /// <exception cref="InvalidCastException">
+        ///     <paramref name="info"/> contains a value that cannot be cast to the correct type.
+        /// </exception>
+        [System.Security.SecuritySafeCritical]
+        protected ImportCardinalityMismatchException(SerializationInfo info, StreamingContext context)
+            : base(info, context)
+        {
+        }
+#endif //FEATURE_SERIALIZATION
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportCardinalityMismatchExceptionDebuggerProxy.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportCardinalityMismatchExceptionDebuggerProxy.cs
new file mode 100644
index 00000000000..d2e92c01707
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportCardinalityMismatchExceptionDebuggerProxy.cs
@@ -0,0 +1,38 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Reflection;
+
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition
+{
+    internal class ImportCardinalityMismatchExceptionDebuggerProxy
+    {
+        private readonly ImportCardinalityMismatchException _exception;
+
+        public ImportCardinalityMismatchExceptionDebuggerProxy(ImportCardinalityMismatchException exception)
+        {
+            Requires.NotNull(exception, "exception");
+
+            this._exception = exception;
+        }
+
+        public Exception InnerException 
+        { 
+            get { return _exception.InnerException; }
+        }
+
+        public string Message
+        {
+            get { return _exception.Message; }
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportManyAttribute.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportManyAttribute.cs
new file mode 100644
index 00000000000..93a09e1fde1
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportManyAttribute.cs
@@ -0,0 +1,168 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Specifies that a property, field, or parameter imports a particular set of exports.
+    /// </summary>
+    [SuppressMessage("Microsoft.Performance", "CA1813:AvoidUnsealedAttributes")]
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter,
+                    AllowMultiple = false, Inherited = false)]
+    public class ImportManyAttribute : Attribute, IAttributedImport
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportManyAttribute"/> class, importing the 
+        ///     set of exports with the default contract name.
+        /// </summary>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the element\item type of 
+        ///         theproperty, field, or parameter type that this is marked with this attribute.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public ImportManyAttribute()
+            : this((string)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportManyAttribute"/> class, importing the
+        ///     set of exports with the contract name derived from the specified type.
+        /// </summary>
+        /// <param name="contractType">
+        ///     A <see cref="Type"/> of which to derive the contract name of the exports to import, or 
+        ///     <see langword="null"/> to use the default contract name.
+        /// </param>
+        /// <remarks>
+        ///     <para>
+        ///         The contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on 
+        ///         <paramref name="contractType"/>.
+        ///     </para>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the property, field, 
+        ///         or parameter type that is marked with this attribute.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public ImportManyAttribute(Type contractType)
+            : this((string)null, contractType)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportManyAttribute"/> class, importing the
+        ///     set of exports with the specified contract name.
+        /// </summary>
+        /// <param name="contractName">
+        ///      A <see cref="String"/> containing the contract name of the exports to import, or 
+        ///      <see langword="null"/> or an empty string ("") to use the default contract name.
+        /// </param>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the property, field, 
+        ///         or parameter type that is marked with this attribute.
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public ImportManyAttribute(string contractName)
+            : this(contractName, (Type)null)
+        {
+        }
+
+        public ImportManyAttribute(string contractName, Type contractType)
+        {
+            this.ContractName = contractName;
+            this.ContractType = contractType;
+        }
+
+        /// <summary>
+        ///     Gets the contract name of the exports to import.
+        /// </summary>
+        /// <value>
+        ///      A <see cref="String"/> containing the contract name of the exports to import. The 
+        ///      default value is an empty string ("").
+        /// </value>
+        public string ContractName { get; private set; }
+
+        /// <summary>
+        ///     Get the contract type of the export to import.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="Type"/> of the export that this import is expecting. The default value is
+        ///     <see langword="null"/> which means that the type will be obtained by looking at the type on
+        ///     the member that this import is attached to. If the type is <see cref="object"/> then the
+        ///     importer is delaring they can accept any exported type.
+        /// </value>
+        public Type ContractType { get; private set; }
+
+        /// <summary>
+        ///     Gets or sets a value indicating whether the property or field will be recomposed
+        ///     when exports that provide the same contract that this import expects, have changed
+        ///     in the container. 
+        /// </summary>
+        /// <value>
+        ///     <see langword="true"/> if the property or field allows for recomposition when exports
+        ///     that provide the same <see cref="ContractName"/> are added or removed from the 
+        ///     <see cref="CompositionContainer"/>; otherwise, <see langword="false"/>. 
+        ///     The default value is <see langword="false"/>.
+        /// </value>
+        public bool AllowRecomposition { get; set; }
+
+        /// <summary>
+        ///     Gets or sets a value indicating that the importer requires a specific 
+        ///     <see cref="CreationPolicy"/> for the exports used to satisfy this import. T
+        /// </summary>
+        /// <value>
+        ///     <see cref="CreationPolicy.Any"/> - default value, used if the importer doesn't 
+        ///         require a specific <see cref="CreationPolicy"/>.
+        /// 
+        ///     <see cref="CreationPolicy.Shared"/> - Requires that all exports used should be shared
+        ///         by everyone in the container.
+        /// 
+        ///     <see cref="CreationPolicy.NonShared"/> - Requires that all exports used should be 
+        ///         non-shared in a container and thus everyone gets their own instance.
+        /// </value>
+        public CreationPolicy RequiredCreationPolicy { get; set; }
+
+        /// <summary>
+        ///     Gets or sets a value indicating that the importer indicating that the composition engine 
+        ///     either should satisfy exports from the local or no local scope.
+        /// </summary>
+        /// <value>
+        ///     <see cref="ImportSource.Any"/> - indicates that importer does not
+        ///         require a specific satisfaction scope"/>.
+        /// 
+        ///     <see cref="ImportSource.Local"/> - indicates the importer requires satisfaction to be
+        ///         from the current container.
+        /// 
+        ///     <see cref="ImportSource.NonLocal"/> - indicates the importer requires satisfaction to be
+        ///         from one of the ancestor containers.
+        /// </value>
+        public ImportSource Source { get; set; }
+
+        ImportCardinality IAttributedImport.Cardinality
+        {
+            get { return ImportCardinality.ZeroOrMore; }
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportSource.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportSource.cs
new file mode 100644
index 00000000000..89797eee8fa
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportSource.cs
@@ -0,0 +1,31 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    /// Option placed on an import to determine how composition searches for exports.
+    /// </summary>
+    public enum ImportSource : int
+    {
+        /// <summary>
+        /// The import can be satisfied with values from the current or parent (or other ancestor) containers  (scopes)
+        /// </summary>
+        Any = 0,
+
+        /// <summary>
+        /// The import can be satisfied with values from the current container (scope) 
+        /// </summary>
+        Local = 1,
+
+        /// <summary>
+        /// The import can only be satisfied with values from the parent container (or other ancestor containers) (scopes) 
+        /// </summary>
+        NonLocal = 2
+
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportingConstructorAttribute.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportingConstructorAttribute.cs
new file mode 100644
index 00000000000..db4a5ebd098
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ImportingConstructorAttribute.cs
@@ -0,0 +1,28 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Specifies that a constructor should be used when constructing an attributed part.
+    /// </summary>
+    /// <remarks>
+    ///     By default, only a default parameter-less constructor, if available, is used to 
+    ///     construct an attributed part. Use this attribute to indicate that a specific constructor 
+    ///     should be used.
+    /// </remarks>
+    [SuppressMessage("Microsoft.Performance", "CA1813:AvoidUnsealedAttributes")]
+    [AttributeUsage(AttributeTargets.Constructor, AllowMultiple = false, Inherited = false)]
+    public class ImportingConstructorAttribute : Attribute
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportingConstructorAttribute"/> class.
+        /// </summary>
+        public ImportingConstructorAttribute()
+        {
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/InheritedExportAttribute.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/InheritedExportAttribute.cs
new file mode 100644
index 00000000000..fb411bc671a
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/InheritedExportAttribute.cs
@@ -0,0 +1,122 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Specifies that a type or interface that provides a particular export.
+    /// </summary>
+    [SuppressMessage("Microsoft.Performance", "CA1813:AvoidUnsealedAttributes")]
+    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Interface, AllowMultiple = true, Inherited = true)]
+    public class InheritedExportAttribute : ExportAttribute
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ExportAttribute"/> class, exporting the
+        ///     type marked with this attribute under the default contract name.
+        /// </summary>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the type itself, 
+        ///         that is marked with this attribute. 
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public InheritedExportAttribute()
+            : this((string)null, (Type)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ExportAttribute"/> class, exporting the
+        ///     type marked with this attribute under a contract name derived from the specified type.
+        /// </summary>
+        /// <param name="contractType">
+        ///     A <see cref="Type"/> of which to derive the contract name to export the type  
+        ///     marked with this attribute, under; or <see langword="null"/> to use the 
+        ///     default contract name.
+        /// </param>
+        /// <remarks>
+        ///     <para>
+        ///         The contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on 
+        ///         <paramref name="contractType"/>.
+        ///     </para>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on the type of the 
+        ///         itself, that is marked with this attribute. 
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public InheritedExportAttribute(Type contractType)
+            : this((string)null, contractType)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ExportAttribute"/> class, exporting the
+        ///     type or member marked with this attribute under the specified contract name.
+        /// </summary>
+        /// <param name="contractName">
+        ///      A <see cref="String"/> containing the contract name to export the type 
+        ///      marked with this attribute, under; or <see langword="null"/> or an empty string 
+        ///      ("") to use the default contract name.
+        /// </param>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on 
+        ///         the type itself that this is marked with this attribute. 
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public InheritedExportAttribute(string contractName)
+            : this(contractName, (Type)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ExportAttribute"/> class, exporting the
+        ///     type or member marked with this attribute under the specified contract name.
+        /// </summary>
+        /// <param name="contractName">
+        ///      A <see cref="String"/> containing the contract name to export the type 
+        ///      marked with this attribute, under; or <see langword="null"/> or an empty string 
+        ///      ("") to use the default contract name.
+        /// </param>
+        /// <param name="contractType">
+        ///     A <see cref="Type"/> of which to derive the contract name to export the type  
+        ///     marked with this attribute, under; or <see langword="null"/> to use the 
+        ///     default contract name.
+        /// </param>
+        /// <remarks>
+        ///     <para>
+        ///         The default contract name is the result of calling 
+        ///         <see cref="AttributedModelServices.GetContractName(Type)"/> on 
+        ///         the type itself that this is marked with this attribute. 
+        ///     </para>
+        ///     <para>
+        ///         The contract name is compared using a case-sensitive, non-linguistic comparison 
+        ///         using <see cref="StringComparer.Ordinal"/>.
+        ///     </para>
+        /// </remarks>
+        public InheritedExportAttribute(string contractName, Type contractType)
+            : base(contractName, contractType)
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataAttributeAttribute.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataAttributeAttribute.cs
new file mode 100644
index 00000000000..81ad7e99c06
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataAttributeAttribute.cs
@@ -0,0 +1,23 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Specifies that an attribute can be used to provide metadata for a type, property, field,
+    ///     or method marked with the <see cref="ExportAttribute"/>.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Class,
+                    AllowMultiple=false, Inherited=true)]
+    public sealed class MetadataAttributeAttribute : Attribute
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="MetadataAttributeAttribute"/> class.
+        /// </summary>
+        public MetadataAttributeAttribute()
+        {
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataServices.cs
new file mode 100644
index 00000000000..ac57d3bafa3
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataServices.cs
@@ -0,0 +1,50 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition
+{
+    internal static class MetadataServices
+    {
+        public static readonly IDictionary<string, object> EmptyMetadata = new ReadOnlyDictionary<string, object>(new Dictionary<string, object>(0));
+
+        public static IDictionary<string, object> AsReadOnly(this IDictionary<string, object> metadata)
+        {
+            if (metadata == null)
+            {
+                return EmptyMetadata;
+            }
+
+            if (metadata is ReadOnlyDictionary<string, object>)
+            {
+                return metadata;
+            }
+
+            return new ReadOnlyDictionary<string, object>(metadata);
+        }
+
+        public static T GetValue<T>(this IDictionary<string, object> metadata, string key)
+        {
+            Assumes.NotNull(metadata, "metadata");
+
+            object untypedValue = true;
+            if (!metadata.TryGetValue(key, out untypedValue))
+            {
+                return default(T);
+            }
+
+            if (untypedValue is T)
+            {
+                return (T)untypedValue;
+            }
+            else
+            {
+                return default(T);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataViewGenerator.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataViewGenerator.cs
new file mode 100644
index 00000000000..b9f2c41fef0
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataViewGenerator.cs
@@ -0,0 +1,381 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Globalization;
+using System.Linq;
+using System.Reflection;
+using System.Threading;
+using Microsoft.Internal;
+using System.Reflection.Emit;
+using System.Collections;
+using System.Security;
+
+namespace System.ComponentModel.Composition
+{
+    // // Assume TMetadataView is
+    // //interface Foo
+    // //{
+    // //    public typeRecord1 Record1 { get; }
+    // //    public typeRecord2 Record2 { get; }
+    // //    public typeRecord3 Record3 { get; }
+    // //    public typeRecord4 Record4 { get; }
+    // //}
+    // // The class to be generated will look approximately like:
+    // public class __Foo__MedataViewProxy : TMetadataView
+    // {
+    //     public __Foo__MedataViewProxy (IDictionary<string, object> metadata)
+    //     {
+    //         if(metadata == null)
+    //         {
+    //             throw InvalidArgumentException("metadata");
+    //         }
+    //         try
+    //         {
+    //              Record1 = (typeRecord1)Record1;
+    //              Record2 = (typeRecord1)Record2;
+    //              Record3 = (typeRecord1)Record3;
+    //              Record4 = (typeRecord1)Record4;
+    //          }
+    //          catch(InvalidCastException ice)
+    //          {
+    //              //Annotate exception .Data with diagnostic info
+    //          }
+    //          catch(NulLReferenceException ice)
+    //          {
+    //              //Annotate exception .Data with diagnostic info
+    //          }
+    //     }
+    //     // Interface
+    //     public typeRecord1 Record1 { get; }
+    //     public typeRecord2 Record2 { get; }
+    //     public typeRecord3 Record3 { get; }
+    //     public typeRecord4 Record4 { get; }
+    // }
+    internal static class MetadataViewGenerator
+    {
+        public const string MetadataViewType       = "MetadataViewType";
+        public const string MetadataItemKey        = "MetadataItemKey";
+        public const string MetadataItemTargetType = "MetadataItemTargetType";
+        public const string MetadataItemSourceType = "MetadataItemSourceType";
+        public const string MetadataItemValue      = "MetadataItemValue";
+
+        private static Lock _lock = new Lock();
+        private static Dictionary<Type, Type> _proxies = new Dictionary<Type, Type>();
+        private static AssemblyName ProxyAssemblyName = new AssemblyName(string.Format(CultureInfo.InvariantCulture, "MetadataViewProxies_{0}", Guid.NewGuid()));
+#if FEATURE_CAS_APTCA
+        private static ModuleBuilder    criticalProxyModuleBuilder;
+#endif //FEATURE_CAS_APTCA
+        private static ModuleBuilder    transparentProxyModuleBuilder;
+
+        private static Type[] CtorArgumentTypes = new Type[] { typeof(IDictionary<string, object>) };
+        private static MethodInfo _mdvDictionaryTryGet = CtorArgumentTypes[0].GetMethod("TryGetValue");
+        private static readonly MethodInfo ObjectGetType = typeof(object).GetMethod("GetType", Type.EmptyTypes);
+#if FEATURE_CAS_APTCA
+        private static CustomAttributeBuilder _securityCriticalBuilder = 
+            new CustomAttributeBuilder(typeof(SecurityCriticalAttribute).GetConstructor(Type.EmptyTypes), new object[0]);
+#endif //FEATURE_CAS_APTCA
+
+        private static AssemblyBuilder CreateProxyAssemblyBuilder(ConstructorInfo constructorInfo)
+        {
+#if FEATURE_CAS_APTCA
+            object[] args = new object[0];
+            CustomAttributeBuilder accessAttribute = new CustomAttributeBuilder(constructorInfo, args);
+            CustomAttributeBuilder[] attributes = { accessAttribute };
+            return AppDomain.CurrentDomain.DefineDynamicAssembly(ProxyAssemblyName, AssemblyBuilderAccess.Run, attributes, SecurityContextSource.CurrentAppDomain);
+#else
+            return AppDomain.CurrentDomain.DefineDynamicAssembly(ProxyAssemblyName, AssemblyBuilderAccess.Run);
+#endif //FEATURE_CAS_APTCA
+        }
+
+        // Must be called with _lock held
+        private static ModuleBuilder GetProxyModuleBuilder(bool requiresCritical)
+        {
+#if FEATURE_CAS_APTCA
+            if(requiresCritical)
+            {
+                // Needed a critical modulebuilder so find or make it
+                if (criticalProxyModuleBuilder == null)
+                {
+                    var assemblyBuilder = CreateProxyAssemblyBuilder(typeof(AllowPartiallyTrustedCallersAttribute).GetConstructor(Type.EmptyTypes));
+                    criticalProxyModuleBuilder = assemblyBuilder.DefineDynamicModule("MetadataViewProxiesModule");
+                }
+                return criticalProxyModuleBuilder;
+            }
+#endif //FEATURE_CAS_APTCA
+            if (transparentProxyModuleBuilder == null)
+            {
+                // make a new assemblybuilder and modulebuilder
+                var assemblyBuilder = CreateProxyAssemblyBuilder(typeof(SecurityTransparentAttribute).GetConstructor(Type.EmptyTypes));
+                transparentProxyModuleBuilder = assemblyBuilder.DefineDynamicModule("MetadataViewProxiesModule");
+            }
+
+            return transparentProxyModuleBuilder;
+        }
+
+        public static Type GenerateView(Type viewType)
+        {
+            Assumes.NotNull(viewType);
+            Assumes.IsTrue(viewType.IsInterface);
+
+            Type proxyType;
+            bool foundProxy;
+
+            using (new ReadLock(_lock))
+            {
+                foundProxy = _proxies.TryGetValue(viewType, out proxyType);
+            }
+
+            // No factory exists
+            if(!foundProxy)
+            {
+                // Try again under a write lock if still none generate the proxy
+                Type generatedProxyType = GenerateInterfaceViewProxyType(viewType);
+                Assumes.NotNull(generatedProxyType);
+
+                using (new WriteLock(_lock))
+                {
+                    if (!_proxies.TryGetValue(viewType, out proxyType))
+                    {
+                        proxyType = generatedProxyType;
+                        _proxies.Add(viewType, proxyType);
+                    }
+                }
+            }
+            return proxyType;
+        }
+
+        private static void GenerateLocalAssignmentFromDefaultAttribute(this ILGenerator IL, DefaultValueAttribute[] attrs, LocalBuilder local)
+        {
+            if (attrs.Length > 0)
+            {
+                DefaultValueAttribute defaultAttribute = attrs[0];
+                IL.LoadValue(defaultAttribute.Value);
+                if ((defaultAttribute.Value != null) && (defaultAttribute.Value.GetType().IsValueType))
+                {
+                    IL.Emit(OpCodes.Box, defaultAttribute.Value.GetType());
+                }
+                IL.Emit(OpCodes.Stloc, local);
+            }
+        }
+
+        private static void GenerateFieldAssignmentFromLocalValue(this ILGenerator IL, LocalBuilder local, FieldBuilder field)
+        {
+            IL.Emit(OpCodes.Ldarg_0);
+            IL.Emit(OpCodes.Ldloc, local);
+            IL.Emit(field.FieldType.IsValueType ? OpCodes.Unbox_Any : OpCodes.Castclass, field.FieldType);
+            IL.Emit(OpCodes.Stfld, field);
+        }
+
+        private static void GenerateLocalAssignmentFromFlag(this ILGenerator IL, LocalBuilder local, bool flag)
+        {
+            IL.Emit(flag ? OpCodes.Ldc_I4_1 : OpCodes.Ldc_I4_0);
+            IL.Emit(OpCodes.Stloc, local);
+        }
+
+        // This must be called with _readerWriterLock held for Write
+        private static Type GenerateInterfaceViewProxyType(Type viewType)
+        {
+            // View type is an interface let's cook an implementation
+            Type proxyType;
+            TypeBuilder proxyTypeBuilder;
+            Type[] interfaces = { viewType };
+            bool requiresCritical = false;
+#if FEATURE_CAS_APTCA
+            requiresCritical = !viewType.IsSecurityTransparent;
+#endif //FEATURE_CAS_APTCA
+
+            var proxyModuleBuilder = GetProxyModuleBuilder(requiresCritical);
+            proxyTypeBuilder = proxyModuleBuilder.DefineType(
+                string.Format(CultureInfo.InvariantCulture, "_proxy_{0}_{1}", viewType.FullName, Guid.NewGuid()),
+                TypeAttributes.Public,
+                typeof(object), 
+                interfaces);
+#if FEATURE_CAS_APTCA
+            if (requiresCritical)
+            {
+                proxyTypeBuilder.SetCustomAttribute(_securityCriticalBuilder);
+            }
+#endif //FEATURE_CAS_APTCA
+            // Implement Constructor
+            ILGenerator proxyCtorIL = proxyTypeBuilder.CreateGeneratorForPublicConstructor(CtorArgumentTypes);
+            LocalBuilder exception = proxyCtorIL.DeclareLocal(typeof(Exception));
+            LocalBuilder exceptionData = proxyCtorIL.DeclareLocal(typeof(IDictionary));
+            LocalBuilder sourceType = proxyCtorIL.DeclareLocal(typeof(Type));
+            LocalBuilder value = proxyCtorIL.DeclareLocal(typeof(object));
+            LocalBuilder usesExportedMD = proxyCtorIL.DeclareLocal(typeof(bool));
+
+            Label tryConstructView = proxyCtorIL.BeginExceptionBlock();
+
+            // Implement interface properties
+            foreach (PropertyInfo propertyInfo in viewType.GetAllProperties())
+            {
+                string fieldName = string.Format(CultureInfo.InvariantCulture, "_{0}_{1}", propertyInfo.Name, Guid.NewGuid());
+
+                // Cache names and type for exception
+                string propertyName = string.Format(CultureInfo.InvariantCulture, "{0}", propertyInfo.Name);
+
+                Type[] propertyTypeArguments = new Type[] { propertyInfo.PropertyType };
+                Type[] optionalModifiers = null;
+                Type[] requiredModifiers = null;
+
+#if FEATURE_ADVANCEDREFLECTION
+                // PropertyInfo does not support GetOptionalCustomModifiers and GetRequiredCustomModifiers on Silverlight
+                optionalModifiers = propertyInfo.GetOptionalCustomModifiers();
+                requiredModifiers = propertyInfo.GetRequiredCustomModifiers();
+                Array.Reverse(optionalModifiers);
+                Array.Reverse(requiredModifiers);
+#endif //FEATURE_ADVANCEDREFLECTION
+
+                // Generate field
+                FieldBuilder proxyFieldBuilder = proxyTypeBuilder.DefineField(
+                    fieldName,
+                    propertyInfo.PropertyType,
+                    FieldAttributes.Private);
+
+                // Generate property
+                PropertyBuilder proxyPropertyBuilder = proxyTypeBuilder.DefineProperty(
+                    propertyName,
+                    PropertyAttributes.None,
+                    propertyInfo.PropertyType,
+                    propertyTypeArguments);
+
+                // Generate constructor code for retrieving the metadata value and setting the field
+                Label tryCastValue = proxyCtorIL.BeginExceptionBlock();
+                Label innerTryCastValue;
+
+                DefaultValueAttribute[] attrs = propertyInfo.GetAttributes<DefaultValueAttribute>(false);
+                if(attrs.Length > 0)
+                {
+                    innerTryCastValue = proxyCtorIL.BeginExceptionBlock();
+                }
+
+                // In constructor set the backing field with the value from the dictionary
+                Label doneGettingDefaultValue = proxyCtorIL.DefineLabel();
+                GenerateLocalAssignmentFromFlag(proxyCtorIL, usesExportedMD, true);
+
+                proxyCtorIL.Emit(OpCodes.Ldarg_1);
+                proxyCtorIL.Emit(OpCodes.Ldstr, propertyInfo.Name);
+                proxyCtorIL.Emit(OpCodes.Ldloca, value);
+                proxyCtorIL.Emit(OpCodes.Callvirt, _mdvDictionaryTryGet);
+                proxyCtorIL.Emit(OpCodes.Brtrue, doneGettingDefaultValue);
+
+                proxyCtorIL.GenerateLocalAssignmentFromFlag(usesExportedMD, false);
+                proxyCtorIL.GenerateLocalAssignmentFromDefaultAttribute(attrs, value);
+
+                proxyCtorIL.MarkLabel(doneGettingDefaultValue);
+                proxyCtorIL.GenerateFieldAssignmentFromLocalValue(value, proxyFieldBuilder);
+                proxyCtorIL.Emit(OpCodes.Leave, tryCastValue);
+
+                // catch blocks for innerTryCastValue start here
+                if (attrs.Length > 0)
+                {
+                    proxyCtorIL.BeginCatchBlock(typeof(InvalidCastException));
+                    {
+                        Label notUsesExportedMd = proxyCtorIL.DefineLabel();
+                        proxyCtorIL.Emit(OpCodes.Ldloc, usesExportedMD);
+                        proxyCtorIL.Emit(OpCodes.Brtrue, notUsesExportedMd);
+                        proxyCtorIL.Emit(OpCodes.Rethrow);
+                        proxyCtorIL.MarkLabel(notUsesExportedMd);
+                        proxyCtorIL.GenerateLocalAssignmentFromDefaultAttribute(attrs, value);
+                        proxyCtorIL.GenerateFieldAssignmentFromLocalValue(value, proxyFieldBuilder);
+                    }
+                    proxyCtorIL.EndExceptionBlock();
+                }
+
+                // catch blocks for tryCast start here
+                proxyCtorIL.BeginCatchBlock(typeof(NullReferenceException));
+                {
+                    proxyCtorIL.Emit(OpCodes.Stloc, exception);
+
+                    proxyCtorIL.GetExceptionDataAndStoreInLocal(exception, exceptionData);
+                    proxyCtorIL.AddItemToLocalDictionary(exceptionData, MetadataItemKey, propertyName);
+                    proxyCtorIL.AddItemToLocalDictionary(exceptionData, MetadataItemTargetType, propertyInfo.PropertyType);
+                    proxyCtorIL.Emit(OpCodes.Rethrow);
+                }
+
+                proxyCtorIL.BeginCatchBlock(typeof(InvalidCastException));
+                {
+                    proxyCtorIL.Emit(OpCodes.Stloc, exception);
+
+                    proxyCtorIL.GetExceptionDataAndStoreInLocal(exception, exceptionData);
+                    proxyCtorIL.AddItemToLocalDictionary(exceptionData, MetadataItemKey, propertyName);
+                    proxyCtorIL.AddItemToLocalDictionary(exceptionData, MetadataItemTargetType, propertyInfo.PropertyType);
+                    proxyCtorIL.Emit(OpCodes.Rethrow);
+                }
+
+                proxyCtorIL.EndExceptionBlock();
+
+                if (propertyInfo.CanWrite)
+                {
+                    // The MetadataView '{0}' is invalid because property '{1}' has a property set method.
+                    throw new NotSupportedException(string.Format(CultureInfo.CurrentCulture,
+                        Strings.InvalidSetterOnMetadataField,
+                        viewType,
+                        propertyName));
+                }
+                if (propertyInfo.CanRead)
+                {
+                    // Generate "get" method implementation.
+                    MethodBuilder getMethodBuilder = proxyTypeBuilder.DefineMethod(
+                        string.Format(CultureInfo.InvariantCulture, "get_{0}", propertyName),
+                        MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.SpecialName | MethodAttributes.NewSlot | MethodAttributes.Virtual | MethodAttributes.Final,
+                        CallingConventions.HasThis,
+                        propertyInfo.PropertyType,
+                        requiredModifiers,
+                        optionalModifiers,
+                        Type.EmptyTypes, null, null);
+
+                    proxyTypeBuilder.DefineMethodOverride(getMethodBuilder, propertyInfo.GetGetMethod());
+#if FEATURE_CAS_APTCA
+                    if(!viewType.IsSecurityTransparent)
+                    {
+                        getMethodBuilder.SetCustomAttribute(_securityCriticalBuilder);
+                    }
+#endif //FEATURE_CAS_APTCA
+                    ILGenerator getMethodIL = getMethodBuilder.GetILGenerator();
+                    getMethodIL.Emit(OpCodes.Ldarg_0);
+                    getMethodIL.Emit(OpCodes.Ldfld, proxyFieldBuilder);
+                    getMethodIL.Emit(OpCodes.Ret);
+
+                    proxyPropertyBuilder.SetGetMethod(getMethodBuilder);
+                }
+            }
+
+            proxyCtorIL.Emit(OpCodes.Leave, tryConstructView);
+
+            // catch blocks for constructView start here
+            proxyCtorIL.BeginCatchBlock(typeof(NullReferenceException));
+            {
+                proxyCtorIL.Emit(OpCodes.Stloc, exception);
+
+                proxyCtorIL.GetExceptionDataAndStoreInLocal(exception, exceptionData);
+                proxyCtorIL.AddItemToLocalDictionary(exceptionData, MetadataViewType, viewType);
+                proxyCtorIL.Emit(OpCodes.Rethrow);
+            }
+            proxyCtorIL.BeginCatchBlock(typeof(InvalidCastException));
+            {
+                proxyCtorIL.Emit(OpCodes.Stloc, exception);
+
+                proxyCtorIL.GetExceptionDataAndStoreInLocal(exception, exceptionData);
+                proxyCtorIL.Emit(OpCodes.Ldloc, value);
+                proxyCtorIL.Emit(OpCodes.Call, ObjectGetType);
+                proxyCtorIL.Emit(OpCodes.Stloc, sourceType);
+                proxyCtorIL.AddItemToLocalDictionary(exceptionData, MetadataViewType, viewType);
+                proxyCtorIL.AddLocalToLocalDictionary(exceptionData, MetadataItemSourceType, sourceType);
+                proxyCtorIL.AddLocalToLocalDictionary(exceptionData, MetadataItemValue, value);
+                proxyCtorIL.Emit(OpCodes.Rethrow);
+            }
+            proxyCtorIL.EndExceptionBlock();
+
+            // Finished implementing interface and constructor
+            proxyCtorIL.Emit(OpCodes.Ret);
+            proxyType = proxyTypeBuilder.CreateType();
+
+            return proxyType;
+        }
+
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataViewImplementationAttribute.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataViewImplementationAttribute.cs
new file mode 100644
index 00000000000..d4834e29914
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataViewImplementationAttribute.cs
@@ -0,0 +1,45 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.Diagnostics.CodeAnalysis;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Specifies that a type, property, field, or method provides a particular export.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Interface, AllowMultiple = false, Inherited = false)]
+    public sealed class MetadataViewImplementationAttribute : Attribute
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="MetadataViewImplementationAttribute"/> class, declaring the
+        ///     type that holds the implementation for the view.
+        /// </summary>
+        /// <param name="typeOfImplementation">
+        ///     A <see cref="Type"/> for the implementation of the MetadataView.
+        /// </param>
+        /// <remarks>
+        ///     <para>
+        ///         By default MetadataViews are generated using reflection emit.  This attribute 
+        ///         allows the developer to specify the ttype that implements the view rather than 
+        ///         using a generated type.
+        ///     </para>
+        /// </remarks>
+        public MetadataViewImplementationAttribute(Type implementationType)
+        {
+            this.ImplementationType = implementationType;
+        }
+
+        /// <summary>
+        ///     Get the type that is used to implement the view to which this attribute is attached.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="Type"/> of the export that is be provided. The default value is
+        ///     <see langword="null"/> which means that the type will be obtained by looking at the type on
+        ///     the member that this export is attached to. 
+        /// </value>
+        public Type ImplementationType { get; private set; }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataViewProvider.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataViewProvider.cs
new file mode 100644
index 00000000000..6c660fcf658
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/MetadataViewProvider.cs
@@ -0,0 +1,130 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Reflection;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition
+{
+    internal static class MetadataViewProvider
+    {
+        [SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes")]
+        public static TMetadataView GetMetadataView<TMetadataView>(IDictionary<string, object> metadata)
+        {
+            Assumes.NotNull(metadata);
+
+            Type metadataViewType = typeof(TMetadataView);
+
+            // If the Metadata dictionary is cast compatible with the passed in type
+            if (metadataViewType.IsAssignableFrom(typeof(IDictionary<string, object>)))
+            {
+                return (TMetadataView)metadata;
+            }
+            // otherwise is it a metadata view
+            else
+            {
+                Type proxyType;
+                if (metadataViewType.IsInterface)
+                {
+                    if(!metadataViewType.IsAttributeDefined<MetadataViewImplementationAttribute>())
+                    {
+                        try
+                        {
+                            proxyType = MetadataViewGenerator.GenerateView(metadataViewType);
+                        }
+                        catch (TypeLoadException ex)
+                        {
+                            throw new NotSupportedException(string.Format(CultureInfo.CurrentCulture, Strings.NotSupportedInterfaceMetadataView, metadataViewType.FullName), ex);
+                        }
+                    }
+                    else
+                    {
+                        var implementationAttribute = metadataViewType.GetFirstAttribute<MetadataViewImplementationAttribute>();
+                        proxyType = implementationAttribute.ImplementationType;
+                        if(proxyType == null)
+                        {
+                            throw new CompositionContractMismatchException(string.Format(CultureInfo.CurrentCulture, 
+                                Strings.ContractMismatch_MetadataViewImplementationCanNotBeNull,
+                                metadataViewType.FullName,
+                                proxyType.FullName));
+                        }
+                        else
+                        {
+                            if(!metadataViewType.IsAssignableFrom(proxyType))
+                            {
+                                throw new CompositionContractMismatchException(string.Format(CultureInfo.CurrentCulture, 
+                                    Strings.ContractMismatch_MetadataViewImplementationDoesNotImplementViewInterface,
+                                    metadataViewType.FullName,
+                                    proxyType.FullName));
+                            }
+                        }
+                    }
+                }
+                else
+                {
+                    proxyType = metadataViewType;
+                }
+
+                // Now we have the type for the proxy create it
+                try
+                {
+                    return (TMetadataView)proxyType.SafeCreateInstance(metadata);
+                }
+                catch (MissingMethodException ex)
+                {
+                    // Unable to create an Instance of the Metadata view '{0}' because a constructor could not be selected.  Ensure that the type implements a constructor which takes an argument of type IDictionary<string, object>.
+                    throw new CompositionContractMismatchException(string.Format(CultureInfo.CurrentCulture,
+                        Strings.CompositionException_MetadataViewInvalidConstructor,
+                        proxyType.AssemblyQualifiedName), ex);
+                }
+                catch (TargetInvocationException ex)
+                {
+                    //Unwrap known failures that we want to present as CompositionContractMismatchException
+                    if(metadataViewType.IsInterface)
+                    {
+                        if(ex.InnerException.GetType() == typeof(InvalidCastException))
+                        {
+                            // Unable to create an Instance of the Metadata view {0} because the exporter exported the metadata for the item {1} with the value {2} as type {3} but the view imports it as type {4}.
+                            throw new CompositionContractMismatchException(string.Format(CultureInfo.CurrentCulture, 
+                                Strings.ContractMismatch_InvalidCastOnMetadataField,
+                                ex.InnerException.Data[MetadataViewGenerator.MetadataViewType],
+                                ex.InnerException.Data[MetadataViewGenerator.MetadataItemKey],
+                                ex.InnerException.Data[MetadataViewGenerator.MetadataItemValue],
+                                ex.InnerException.Data[MetadataViewGenerator.MetadataItemSourceType],
+                                ex.InnerException.Data[MetadataViewGenerator.MetadataItemTargetType]), ex);
+                        }
+                        else if (ex.InnerException.GetType() == typeof(NullReferenceException))
+                        {
+                            // Unable to create an Instance of the Metadata view {0} because the exporter exported the metadata for the item {1} with a null value and null is not a valid value for type {2}.
+                            throw new CompositionContractMismatchException(string.Format(CultureInfo.CurrentCulture,
+                                Strings.ContractMismatch_NullReferenceOnMetadataField,
+                                ex.InnerException.Data[MetadataViewGenerator.MetadataViewType],
+                                ex.InnerException.Data[MetadataViewGenerator.MetadataItemKey],
+                                ex.InnerException.Data[MetadataViewGenerator.MetadataItemTargetType]), ex);
+                        }
+                    }
+                    throw;
+                }
+            }
+        }
+
+        public static bool IsViewTypeValid(Type metadataViewType)
+        {
+            Assumes.NotNull(metadataViewType);
+
+            // If the Metadata dictionary is cast compatible with the passed in type
+            if (ExportServices.IsDefaultMetadataViewType(metadataViewType)
+            ||  metadataViewType.IsInterface
+            ||  ExportServices.IsDictionaryConstructorViewType(metadataViewType))
+            {
+                return true;
+            }
+
+            return false;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/PartCreationPolicyAttribute.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/PartCreationPolicyAttribute.cs
new file mode 100644
index 00000000000..43d0fc9feac
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/PartCreationPolicyAttribute.cs
@@ -0,0 +1,36 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Specifies <see cref="CreationPolicy"/> for a given <see cref="ComposablePart" />.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
+    public sealed class PartCreationPolicyAttribute : Attribute
+    {
+        internal static PartCreationPolicyAttribute Default = new PartCreationPolicyAttribute(CreationPolicy.Any);
+        internal static PartCreationPolicyAttribute Shared = new PartCreationPolicyAttribute(CreationPolicy.Shared);
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="PartCreationPolicyAttribute"/> class.
+        /// </summary>
+        public PartCreationPolicyAttribute(CreationPolicy creationPolicy)
+        {
+            this.CreationPolicy = creationPolicy;
+        }
+
+        /// <summary>
+        ///     Gets or sets a value indicating the creation policy of the attributed part.
+        /// </summary>
+        /// <value>
+        ///     One of the <see cref="CreationPolicy"/> values indicating the creation policy of the 
+        ///     attributed part. The default is 
+        ///     <see cref="System.ComponentModel.Composition.CreationPolicy.Any"/>.
+        /// </value>
+        public CreationPolicy CreationPolicy { get; private set; }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/PartMetadataAttribute.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/PartMetadataAttribute.cs
new file mode 100644
index 00000000000..a75aa4e18d3
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/PartMetadataAttribute.cs
@@ -0,0 +1,58 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Specifies metadata for a type to be used as a <see cref="ComposablePartDefinition"/> and
+    ///     <see cref="ComposablePart"/>.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Class, AllowMultiple = true, Inherited = false)]
+    public sealed class PartMetadataAttribute : Attribute
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="PartMetadataAttribute"/> with the 
+        ///     specified name and metadata value.
+        /// </summary>
+        /// <param name="name">
+        ///     A <see cref="String"/> containing the name of the metadata value; or 
+        ///     <see langword="null"/> to use an empty string ("").
+        /// </param>
+        /// <param name="value">
+        ///     An <see cref="object"/> containing the metadata value. This can be 
+        ///     <see langword="null"/>.
+        /// </param>
+        public PartMetadataAttribute(string name, object value)
+        {
+            this.Name = name ?? string.Empty;
+            this.Value = value;
+        }
+
+        /// <summary>
+        ///     Gets the name of the metadata value.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="String"/> containing the name of the metadata value.
+        /// </value>
+        public string Name
+        {
+            get;
+            private set;
+        }
+
+        /// <summary>
+        ///     Gets the metadata value.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="object"/> containing the metadata value.
+        /// </value>
+        public object Value
+        {
+            get;
+            private set;
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/PartNotDiscoverableAttribute.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/PartNotDiscoverableAttribute.cs
new file mode 100644
index 00000000000..02c82467a6a
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/PartNotDiscoverableAttribute.cs
@@ -0,0 +1,23 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition
+{
+    /// <summary>
+    ///     Place on a type that should not be discovered as a <see cref="ComposablePart" /> in
+    ///     a <see cref="ComposablePartCatalog" />.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
+    public sealed class PartNotDiscoverableAttribute : Attribute
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="PartNotDiscoverableAttribute"/> class.
+        /// </summary>
+        public PartNotDiscoverableAttribute()
+        {
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePart.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePart.cs
new file mode 100644
index 00000000000..8eea96fc660
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePart.cs
@@ -0,0 +1,213 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.Contracts;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    /// <summary>
+    ///     Defines the <see langword="abstract"/> base class for composable parts, which 
+    ///     import and produce exported values.
+    /// </summary>
+#if CONTRACTS_FULL
+    [ContractClass(typeof(ComposablePartContract))]
+#endif
+    public abstract class ComposablePart
+    {
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ComposablePart"/> class.
+        /// </summary>
+        protected ComposablePart()
+        {
+        }
+
+        /// <summary>
+        ///     Gets the export definitions that describe the exported values provided by the part.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="ExportDefinition"/> objects describing
+        ///     the exported values provided by the <see cref="ComposablePart"/>.
+        /// </value>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ComposablePart"/> has been disposed of.
+        /// </exception>
+        /// <remarks>
+        ///     <para>
+        ///         <note type="inheritinfo">
+        ///             If the <see cref="ComposablePart"/> was created from a 
+        ///             <see cref="ComposablePartDefinition"/>, this property should return the result of 
+        ///             <see cref="ComposablePartDefinition.ExportDefinitions"/>.
+        ///         </note>
+        ///      </para>
+        ///      <para>
+        ///         <note type="inheritinfo">
+        ///             Overriders of this property should never return <see langword="null"/>.
+        ///             If the <see cref="ComposablePart"/> does not have exports, return an empty 
+        ///             <see cref="IEnumerable{T}"/> instead.
+        ///         </note>
+        ///     </para>
+        /// </remarks>
+        public abstract IEnumerable<ExportDefinition> ExportDefinitions { get; }
+
+        /// <summary>
+        ///     Gets the import definitions that describe the imports required by the part.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="ImportDefinition"/> objects describing
+        ///     the imports required by the <see cref="ComposablePart"/>.
+        /// </value>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ComposablePart"/> has been disposed of.
+        /// </exception>
+        /// <remarks>
+        ///     <para>
+        ///         <note type="inheritinfo">
+        ///             If the <see cref="ComposablePart"/> was created from a 
+        ///             <see cref="ComposablePartDefinition"/>, this property should return the result of 
+        ///             <see cref="ComposablePartDefinition.ImportDefinitions"/>.
+        ///         </note>
+        ///      </para>
+        ///      <para>
+        ///         <note type="inheritinfo">
+        ///             Overrides of this property should never return <see langword="null"/>.
+        ///             If the <see cref="ComposablePart"/> does not have imports, return an empty 
+        ///             <see cref="IEnumerable{T}"/> instead.
+        ///         </note>
+        ///     </para>
+        /// </remarks>
+        public abstract IEnumerable<ImportDefinition> ImportDefinitions { get; }
+
+        /// <summary>
+        ///     Gets the metadata of the part.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IDictionary{TKey, TValue}"/> containing the metadata of the 
+        ///     <see cref="ComposablePart"/>. The default is an empty, read-only
+        ///     <see cref="IDictionary{TKey, TValue}"/>.
+        /// </value>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ComposablePart"/> has been disposed of.
+        /// </exception>
+        /// <remarks>
+        ///     <para>
+        ///         <note type="inheritinfo">
+        ///             If the <see cref="ComposablePart"/> was created from a 
+        ///             <see cref="ComposablePartDefinition"/>, this property should return the result of 
+        ///             <see cref="ComposablePartDefinition.Metadata"/>.
+        ///         </note>
+        ///      </para>
+        ///      <para>
+        ///         <note type="inheritinfo">
+        ///             Overriders of this property should return a read-only
+        ///             <see cref="IDictionary{TKey, TValue}"/> object with a case-sensitive, 
+        ///             non-linguistic comparer, such as <see cref="StringComparer.Ordinal"/>, 
+        ///             and should never return <see langword="null"/>. If the 
+        ///             <see cref="ComposablePart"/> does not contain metadata, return an 
+        ///             empty <see cref="IDictionary{TKey, TValue}"/> instead.
+        ///         </note>
+        ///      </para>
+        /// </remarks>
+        public virtual IDictionary<string, object> Metadata
+        {
+            get 
+            {
+                return MetadataServices.EmptyMetadata; 
+            }
+        }
+
+        /// <summary>
+        ///     Called by the composition engine when all required imports on the part have been
+        ///     satisfied.
+        /// </summary>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ComposablePart"/> has been disposed of.
+        /// </exception>
+        /// <exception cref="ComposablePartException">
+        ///     An error occurred activating the <see cref="ComposablePart"/>.
+        /// </exception>
+        public virtual void Activate()
+        {
+        }
+
+        /// <summary>
+        ///     Gets the exported value described by the specified definition.
+        /// </summary>
+        /// <param name="definition">
+        ///     One of the <see cref="ExportDefinition"/> objects from the 
+        ///     <see cref="ExportDefinitions"/> property describing the exported value
+        ///     to return.
+        /// </param>
+        /// <returns>
+        ///     The exported value described by <paramref name="definition"/>.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="definition"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="definition"/> did not originate from the <see cref="ExportDefinitions"/>
+        ///     property on the <see cref="ComposablePart"/>.
+        /// </exception>
+        /// <exception cref="InvalidOperationException">
+        ///     One or more pre-requisite imports, indicated by <see cref="ImportDefinition.IsPrerequisite"/>,
+        ///     have not been set.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ComposablePart"/> has been disposed of.
+        /// </exception>
+        /// <exception cref="ComposablePartException">
+        ///     An error occurred getting the exported value described by the <see cref="ExportDefinition"/>.
+        /// </exception>
+        public abstract object GetExportedValue(ExportDefinition definition);
+
+        /// <summary>
+        ///     Sets the import described by the specified definition with the specified exports.
+        /// </summary>
+        /// <param name="definition">
+        ///     One of the <see cref="ImportDefinition"/> objects from the 
+        ///     <see cref="ImportDefinitions"/> property describing the import to be set.
+        /// </param>
+        /// <param name="exports">
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="Export"/> objects of which 
+        ///     to set the import described by <paramref name="definition"/>.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="definition"/> is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="exports"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="definition"/> did not originate from the <see cref="ImportDefinitions"/>
+        ///     property on the <see cref="ComposablePart"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="exports"/> contains an element that is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="exports"/> is empty and <see cref="ImportDefinition.Cardinality"/> is 
+        ///     <see cref="ImportCardinality.ExactlyOne"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="exports"/> contains more than one element and 
+        ///     <see cref="ImportDefinition.Cardinality"/> is <see cref="ImportCardinality.ZeroOrOne"/> or 
+        ///     <see cref="ImportCardinality.ExactlyOne"/>.
+        /// </exception>
+        /// <exception cref="InvalidOperationException">
+        ///     <see cref="Activate"/> has been previously called and 
+        ///     <see cref="ImportDefinition.IsRecomposable"/> is <see langword="false"/>.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ComposablePart"/> has been disposed of.
+        /// </exception>
+        /// <exception cref="ComposablePartException">
+        ///     An error occurred setting the import described by the <see cref="ImportDefinition"/>.
+        /// </exception>
+        public abstract void SetImport(ImportDefinition definition, IEnumerable<Export> exports);
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartCatalog.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartCatalog.cs
new file mode 100644
index 00000000000..d296543a9fb
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartCatalog.cs
@@ -0,0 +1,188 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Linq;
+using System.Threading;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using System.ComponentModel.Composition.Hosting;
+
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    /// <summary>
+    ///     Defines the <see langword="abstract"/> base class for composable part catalogs, which produce
+    ///     and return <see cref="ComposablePartDefinition"/> objects.
+    /// </summary>
+    /// <remarks>
+    ///     This type is thread safe.
+    /// </remarks>
+    [DebuggerTypeProxy(typeof(ComposablePartCatalogDebuggerProxy))]
+    public abstract class ComposablePartCatalog : IEnumerable<ComposablePartDefinition>, IDisposable
+    {
+        private bool _isDisposed;
+        private volatile IQueryable<ComposablePartDefinition> _queryableParts = null;
+
+        private static readonly List<Tuple<ComposablePartDefinition, ExportDefinition>> _EmptyExportsList = new List<Tuple<ComposablePartDefinition, ExportDefinition>>();
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ComposablePartCatalog"/> class.
+        /// </summary>
+        protected ComposablePartCatalog()
+        {
+        }
+
+        /// <summary>
+        ///     Gets the part definitions of the catalog.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="IQueryable{T}"/> of <see cref="ComposablePartDefinition"/> objects of the 
+        ///     <see cref="ComposablePartCatalog"/>.
+        /// </value>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ComposablePartCatalog"/> has been disposed of.
+        /// </exception>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Overriders of this property should never return <see langword="null"/>.
+        ///     </note>
+        /// </remarks>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Never)]
+        public virtual IQueryable<ComposablePartDefinition> Parts 
+        {
+            get
+            {
+                this.ThrowIfDisposed();
+                if(this._queryableParts == null)
+                {
+                    // Guarantee one time only set _queryableParts
+                    var p = this.AsQueryable();
+                    // NOTE : According to http://msdn.microsoft.com/en-us/library/4bw5ewxy.aspx, the warning is bogus when used with Interlocked API.
+#pragma warning disable 420
+                    Interlocked.CompareExchange(ref this._queryableParts, p, null);
+#pragma warning restore 420
+                    Assumes.NotNull(this._queryableParts);
+                }
+                return this._queryableParts;
+            }
+        }
+
+        /// <summary>
+        ///     Returns the export definitions that match the constraint defined by the specified definition.
+        /// </summary>
+        /// <param name="definition">
+        ///     The <see cref="ImportDefinition"/> that defines the conditions of the 
+        ///     <see cref="ExportDefinition"/> objects to return.
+        /// </param>
+        /// <returns>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="Tuple{T1, T2}"/> containing the 
+        ///     <see cref="ExportDefinition"/> objects and their associated 
+        ///     <see cref="ComposablePartDefinition"/> for objects that match the constraint defined 
+        ///     by <paramref name="definition"/>.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="definition"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ObjectDisposedException">
+        ///     The <see cref="ComposablePartCatalog"/> has been disposed of.
+        /// </exception>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Overriders of this property should never return <see langword="null"/>, if no 
+        ///         <see cref="ExportDefinition"/> match the conditions defined by 
+        ///         <paramref name="definition"/>, return an empty <see cref="IEnumerable{T}"/>.
+        ///     </note>
+        /// </remarks>
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public virtual IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>> GetExports(ImportDefinition definition)
+        {
+            this.ThrowIfDisposed();
+
+            Requires.NotNull(definition, "definition");
+            Contract.Ensures(Contract.Result<IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>>>() != null);
+
+            List<Tuple<ComposablePartDefinition, ExportDefinition>> exports = null;
+            var candidateParts = this.GetCandidateParts(definition);
+            if (candidateParts != null)
+            {
+                foreach (var part in candidateParts)
+                {
+                    var partExports = part.GetExports(definition);
+                    if (partExports != ComposablePartDefinition._EmptyExports)
+                    {
+                        exports = exports.FastAppendToListAllowNulls(partExports);
+                    }
+                }
+            }
+
+            return exports ?? _EmptyExportsList;
+        }
+
+
+        internal virtual IEnumerable<ComposablePartDefinition> GetCandidateParts(ImportDefinition definition)
+        {
+            return this;
+        }
+
+
+        /// <summary>
+        ///     Releases the unmanaged resources used by the <see cref="ComposablePartCatalog"/> and 
+        ///     optionally releases the managed resources.
+        /// </summary>
+        /// <param name="disposing">
+        ///     <see langword="true"/> to release both managed and unmanaged resources; 
+        ///     <see langword="false"/> to release only unmanaged resources.
+        /// </param>
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        protected virtual void Dispose(bool disposing) 
+        {
+            this._isDisposed = true;
+        }
+
+        [DebuggerStepThrough]
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053", Justification = "Suppressing warning because this validator has no public contract")]
+        private void ThrowIfDisposed()
+        {
+            if (this._isDisposed)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+
+        //
+        // If neither Parts nor GetEnumerator() is overriden then return an empty list
+        // If GetEnumerator is overridden this code should not be invoked:  ReferenceAssemblies mark it as Abstract or Not present
+        // We verify whether Parts is overriden by seeing if the object returns matched the one cached for this instance
+        // Note: a query object is only cached if Parts is invoked on a catalog which did not implement it
+        //      Because reference assemblies do not expose Parts and we no longer use it, it should not get invoked by 3rd parties
+        //      Because the reference assemblies mark GetEnumerator as Abstract 3rd party code should not lack an implementation
+        //      That implementation should not try to call this implementation
+        // Our code doies delegate to Parts in the DebuggerProxies of course.
+        //
+        public virtual IEnumerator<ComposablePartDefinition> GetEnumerator()
+        {
+            var parts = this.Parts;
+            if(object.ReferenceEquals(parts, this._queryableParts))
+            {
+                return Enumerable.Empty<ComposablePartDefinition>().GetEnumerator();
+            }
+            return parts.GetEnumerator();
+        }
+
+        Collections.IEnumerator Collections.IEnumerable.GetEnumerator()
+        {
+            return this.GetEnumerator();
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartCatalogDebuggerProxy.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartCatalogDebuggerProxy.cs
new file mode 100644
index 00000000000..15f0031dc00
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartCatalogDebuggerProxy.cs
@@ -0,0 +1,33 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.ObjectModel;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    // This proxy is needed to pretty up ComposablePartCatalog.Parts; IQueryable<T> 
+    // instances are not displayed in a very friendly way in the debugger.
+    internal class ComposablePartCatalogDebuggerProxy
+    {
+        private readonly ComposablePartCatalog _catalog;
+
+        public ComposablePartCatalogDebuggerProxy(ComposablePartCatalog catalog) 
+        {
+            Requires.NotNull(catalog, "catalog");
+
+            this._catalog = catalog;
+        }
+
+        public ReadOnlyCollection<ComposablePartDefinition> Parts
+        {
+            // NOTE: This shouldn't be cached, so that on every query of
+            // the current value of the underlying catalog is respected.
+            // We use ReadOnlyCollection as arrays do not have the 
+            // appropriate debugger display attributes applied to them.
+            get { return this._catalog.Parts.ToReadOnlyCollection(); }
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartDefinition.cs
new file mode 100644
index 00000000000..013a3d101d6
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartDefinition.cs
@@ -0,0 +1,131 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.Contracts;
+using System.Linq;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    /// <summary>
+    ///     Defines the <see langword="abstract"/> base class for composable part definitions, which 
+    ///     describe, and allow the creation of, <see cref="ComposablePart"/> objects.
+    /// </summary>
+#if CONTRACTS_FULL
+    [ContractClass(typeof(ComposablePartDefinitionContract))]
+#endif
+    public abstract class ComposablePartDefinition
+    {
+        static internal readonly IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>> _EmptyExports = Enumerable.Empty<Tuple<ComposablePartDefinition, ExportDefinition>>();
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ComposablePartDefinition"/> class.
+        /// </summary>
+        protected ComposablePartDefinition()
+        {
+        }
+
+        /// <summary>
+        ///     Gets the export definitions that describe the exported values provided by parts 
+        ///     created by the definition.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="ExportDefinition"/> objects describing
+        ///     the exported values provided by <see cref="ComposablePart"/> objects created by the 
+        ///     <see cref="ComposablePartDefinition"/>.
+        /// </value>
+        /// <remarks>
+         ///     <note type="inheritinfo">
+        ///         Overrides of this property should never return <see langword="null"/>.
+        ///         If the <see cref="ComposablePart"/> objects created by the 
+        ///         <see cref="ComposablePartDefinition"/> do not provide exported values, return 
+        ///         an empty <see cref="IEnumerable{T}"/> instead.
+        ///     </note>
+        /// </remarks>
+        public abstract IEnumerable<ExportDefinition> ExportDefinitions { get; }
+
+        /// <summary>
+        ///     Gets the import definitions that describe the imports required by parts created 
+        ///     by the definition.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="ImportDefinition"/> objects describing
+        ///     the imports required by <see cref="ComposablePart"/> objects created by the 
+        ///     <see cref="ComposablePartDefinition"/>.
+        /// </value>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Overriders of this property should never return <see langword="null"/>.
+        ///         If the <see cref="ComposablePart"/> objects created by the 
+        ///         <see cref="ComposablePartDefinition"/> do not have imports, return an empty 
+        ///         <see cref="IEnumerable{T}"/> instead.
+        ///     </note>
+        /// </remarks>
+        public abstract IEnumerable<ImportDefinition> ImportDefinitions { get; }
+
+        /// <summary>
+        ///     Gets the metadata of the definition.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IDictionary{TKey, TValue}"/> containing the metadata of the 
+        ///     <see cref="ComposablePartDefinition"/>. The default is an empty, read-only
+        ///     <see cref="IDictionary{TKey, TValue}"/>.
+        /// </value>
+        /// <remarks>
+        ///     <para>
+        ///         <note type="inheritinfo">
+        ///             Overriders of this property should return a read-only
+        ///             <see cref="IDictionary{TKey, TValue}"/> object with a case-sensitive, 
+        ///             non-linguistic comparer, such as <see cref="StringComparer.Ordinal"/>, 
+        ///             and should never return <see langword="null"/>. If the 
+        ///             <see cref="ComposablePartDefinition"/> does contain metadata, 
+        ///             return an empty <see cref="IDictionary{TKey, TValue}"/> instead.
+        ///         </note>
+        ///     </para>
+        /// </remarks>
+        public virtual IDictionary<string, object> Metadata 
+        {
+            get { return MetadataServices.EmptyMetadata; } 
+        }
+
+        /// <summary>
+        ///     Creates a new instance of a part that the definition describes.
+        /// </summary>
+        /// <returns>
+        ///     The created <see cref="ComposablePart"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         <note type="inheritinfo">
+        ///             Derived types overriding this method should return a new instance of a 
+        ///             <see cref="ComposablePart"/> on every invoke and should never return 
+        ///             <see langword="null"/>.
+        ///         </note>
+        ///     </para>
+        /// </remarks>
+        public abstract ComposablePart CreatePart();
+
+        internal virtual IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>> GetExports(ImportDefinition definition)
+        {
+            List<Tuple<ComposablePartDefinition, ExportDefinition>> exports = null;
+            foreach (var export in this.ExportDefinitions)
+            {
+                if (definition.IsConstraintSatisfiedBy(export))
+                {
+                    if (exports == null)
+                    {
+                        exports = new List<Tuple<ComposablePartDefinition, ExportDefinition>>();
+                    }
+                    exports.Add(new Tuple<ComposablePartDefinition, ExportDefinition>(this, export));
+                }
+            }
+
+            return exports ?? _EmptyExports;
+        }
+
+        internal virtual ComposablePartDefinition GetGenericPartDefinition()
+        {
+            return null;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartException.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartException.cs
new file mode 100644
index 00000000000..dcac158b059
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartException.cs
@@ -0,0 +1,181 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Diagnostics;
+using System.Runtime.Serialization;
+using System.Security.Permissions;
+using Microsoft.Internal;
+using Microsoft.Internal.Runtime.Serialization;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    /// <summary>
+    ///     The exception that is thrown when an error occurs when calling methods on a
+    ///     <see cref="ComposablePart"/>.
+    /// </summary>
+    [Serializable]
+    [DebuggerTypeProxy(typeof(ComposablePartExceptionDebuggerProxy))]
+    [DebuggerDisplay("{Message}")]
+    public class ComposablePartException : Exception
+    {
+        private readonly ICompositionElement _element;
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ComposablePartException"/> class.
+        /// </summary>
+        public ComposablePartException()
+            : this((string)null, (ICompositionElement)null, (Exception)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ComposablePartException"/> class 
+        ///     with the specified error message.
+        /// </summary>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="ComposablePartException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.Message"/> property to its default value.
+        /// </param>
+        /// <param name="element">
+        ///     The <see cref="ICompositionElement"/> that is the cause of the
+        ///     <see cref="ComposablePartException"/>; or <see langword="null"/> to set
+        ///     the <see cref="ComposablePartException.Element"/> property to 
+        ///     <see langword="null"/>.
+        /// </param>
+        public ComposablePartException(string message)
+            : this(message, (ICompositionElement)null, (Exception)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ComposablePartException"/> class 
+        ///     with the specified error message and composition element that is the cause of
+        ///     the exception.
+        /// </summary>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="ComposablePartException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.Message"/> property to its default value.
+        /// </param>
+        public ComposablePartException(string message, ICompositionElement element)
+            : this(message, element, (Exception)null)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ComposablePartException"/> class 
+        ///     with the specified error message and exception that is the cause of the  
+        ///     exception.
+        /// </summary>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="ComposablePartException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.Message"/> property to its default value.
+        /// </param>
+        /// <param name="innerException">
+        ///     The <see cref="Exception"/> that is the underlying cause of the 
+        ///     <see cref="ComposablePartException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.InnerException"/> property to <see langword="null"/>.
+        /// </param>
+        public ComposablePartException(string message, Exception innerException)
+            : this(message, (ICompositionElement)null, innerException)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ComposablePartException"/> class 
+        ///     with the specified error message, and composition element and exception that 
+        ///     are the cause of the exception.
+        /// </summary>
+        /// <param name="message">
+        ///     A <see cref="String"/> containing a message that describes the 
+        ///     <see cref="ComposablePartException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.Message"/> property to its default value.
+        /// </param>
+        /// <param name="element">
+        ///     The <see cref="ICompositionElement"/> that is the cause of the
+        ///     <see cref="ComposablePartException"/>; or <see langword="null"/> to set
+        ///     the <see cref="ComposablePartException.Element"/> property to 
+        ///     <see langword="null"/>.
+        /// </param>
+        /// <param name="innerException">
+        ///     The <see cref="Exception"/> that is the underlying cause of the 
+        ///     <see cref="ComposablePartException"/>; or <see langword="null"/> to set
+        ///     the <see cref="Exception.InnerException"/> property to <see langword="null"/>.
+        /// </param>
+        public ComposablePartException(string message, ICompositionElement element, Exception innerException)
+            : base(message, innerException)
+        {
+            _element = element;
+        }
+
+#if FEATURE_SERIALIZATION
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ComposablePartException"/> class 
+        ///     with the specified serialization data.
+        /// </summary>
+        /// <param name="info">
+        ///     The <see cref="SerializationInfo"/> that holds the serialized object data about the 
+        ///     <see cref="ComposablePartException"/>.
+        /// </param>
+        /// <param name="context">
+        ///     The <see cref="StreamingContext"/> that contains contextual information about the 
+        ///     source or destination.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="info"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="SerializationException">
+        ///     <paramref name="info"/> is missing a required value.
+        /// </exception>
+        /// <exception cref="InvalidCastException">
+        ///     <paramref name="info"/> contains a value that cannot be cast to the correct type.
+        /// </exception>
+        [System.Security.SecuritySafeCritical]
+        protected ComposablePartException(SerializationInfo info, StreamingContext context)
+            : base(info, context)
+        {
+            _element = info.GetValue<ICompositionElement>("Element");
+        }
+
+#endif //FEATURE_SERIALIZATION
+
+        /// <summary>
+        ///     Gets the composition element that is the cause of the exception.
+        /// </summary>
+        /// <value>
+        ///     The <see cref="ICompositionElement"/> that is the cause of the
+        ///     <see cref="ComposablePartException"/>. The default is <see langword="null"/>.
+        /// </value>
+        public ICompositionElement Element
+        {
+            get { return _element; }
+        }
+
+#if FEATURE_SERIALIZATION
+        /// <summary>
+        ///     Gets the serialization data of the exception.
+        /// </summary>
+        /// <param name="info">
+        ///     The <see cref="SerializationInfo"/> that holds the serialized object data about the 
+        ///     <see cref="ComposablePartException"/>.
+        /// </param>
+        /// <param name="context">
+        ///     The <see cref="StreamingContext"/> that contains contextual information about the 
+        ///     source or destination.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="info"/> is <see langword="null"/>.
+        /// </exception>
+        [System.Security.SecurityCritical]
+        public override void GetObjectData(SerializationInfo info, StreamingContext context)
+        {
+            base.GetObjectData(info, context);
+
+            info.AddValue("Element", _element.ToSerializableElement());
+        }
+#endif //FEATURE_SERIALIZATION
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartExceptionDebuggerProxy.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartExceptionDebuggerProxy.cs
new file mode 100644
index 00000000000..6e4d0366fc3
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ComposablePartExceptionDebuggerProxy.cs
@@ -0,0 +1,43 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics;
+using System.Reflection;
+
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    internal class ComposablePartExceptionDebuggerProxy
+    {
+        private readonly ComposablePartException _exception;
+
+        public ComposablePartExceptionDebuggerProxy(ComposablePartException exception)
+        {
+            Requires.NotNull(exception, "exception");
+
+            this._exception = exception;
+        }
+
+        public ICompositionElement Element
+        {
+            get { return _exception.Element; }
+        }
+
+        public Exception InnerException 
+        { 
+            get { return _exception.InnerException; }
+        }
+
+        public string Message
+        {
+            get { return _exception.Message; }
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/CompositionElement.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/CompositionElement.cs
new file mode 100644
index 00000000000..23f7677f571
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/CompositionElement.cs
@@ -0,0 +1,30 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Diagnostics;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    // Represents the ICompositionElement placeholder for an 
+    // object that does not implement ICompositionElement
+    [DebuggerTypeProxy(typeof(CompositionElementDebuggerProxy))]
+    [Serializable]
+    internal class CompositionElement : SerializableCompositionElement
+    {
+        private static readonly ICompositionElement UnknownOrigin = new SerializableCompositionElement(Strings.CompositionElement_UnknownOrigin, (ICompositionElement)null);
+        private readonly object _underlyingObject;
+
+        public CompositionElement(object underlyingObject)
+            : base(underlyingObject.ToString(), UnknownOrigin)
+        {
+            this._underlyingObject = underlyingObject;
+        }
+
+        public object UnderlyingObject
+        {
+            get { return _underlyingObject; }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/CompositionElementDebuggerProxy.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/CompositionElementDebuggerProxy.cs
new file mode 100644
index 00000000000..00442c50646
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/CompositionElementDebuggerProxy.cs
@@ -0,0 +1,39 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    // Because the debugger displays only the members available on ICompositionElement 
+    // when viewing CompositionError.Element in the watch and data tips windows, we 
+    // need this proxy so that the underlying object wrapped by the CompositionElement 
+    // placeholder is displayed by default.
+    internal class CompositionElementDebuggerProxy
+    {
+        private readonly CompositionElement _element;
+
+        public CompositionElementDebuggerProxy(CompositionElement element) 
+        {
+            Requires.NotNull(element, "element");
+
+            this._element = element;
+        }
+
+        public string DisplayName
+        {
+            get { return this._element.DisplayName; }
+        }
+
+        public ICompositionElement Origin
+        {
+            get { return this._element.Origin; }
+        }
+
+        public object UnderlyingObject
+        {
+            get { return this._element.UnderlyingObject; }
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/CompositionElementExtensions.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/CompositionElementExtensions.cs
new file mode 100644
index 00000000000..47e8cfb888d
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/CompositionElementExtensions.cs
@@ -0,0 +1,82 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    internal static class CompositionElementExtensions
+    {
+#if FEATURE_SERIALIZATION
+        public static ICompositionElement ToSerializableElement(this ICompositionElement element)
+        {
+            return SerializableCompositionElement.FromICompositionElement(element);
+        }
+#endif //FEATURE_SERIALIZATION
+        public static ICompositionElement ToElement(this Export export)
+        {
+            // First try the export
+            ICompositionElement element = export as ICompositionElement;
+            if (element != null)
+            {
+                return element;
+            }
+
+            // Otherwise, try the definition
+            return ToElement(export.Definition);
+        }
+
+        public static ICompositionElement ToElement(this ExportDefinition definition)
+        {
+            return ToElementCore(definition);
+        }
+
+        public static ICompositionElement ToElement(this ImportDefinition definition)
+        {
+            return ToElementCore(definition);
+        }
+
+        public static ICompositionElement ToElement(this ComposablePart part)
+        {
+            return ToElementCore(part);
+        }
+
+        public static ICompositionElement ToElement(this ComposablePartDefinition definition)
+        {
+            return ToElementCore(definition);
+        }
+
+        public static string GetDisplayName(this ComposablePartDefinition definition)
+        {
+            return GetDisplayNameCore(definition);
+        }
+
+        public static string GetDisplayName(this ComposablePartCatalog catalog)
+        {
+            return GetDisplayNameCore(catalog);
+        }
+
+        private static string GetDisplayNameCore(object value)
+        {
+            ICompositionElement element = value as ICompositionElement;
+            if (element != null)
+            {
+                return element.DisplayName;
+            }
+
+            return value.ToString();
+        }
+
+        private static ICompositionElement ToElementCore(object value)
+        {
+            ICompositionElement element = value as ICompositionElement;
+            if (element != null)
+            {
+                return element;
+            }
+
+            return new CompositionElement(value);
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ContractBasedImportDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ContractBasedImportDefinition.cs
new file mode 100644
index 00000000000..a221e686a43
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ContractBasedImportDefinition.cs
@@ -0,0 +1,397 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Hosting;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Globalization;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Text;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    /// <summary>
+    ///     Represents a contract name and metadata-based import 
+    ///     required by a <see cref="ComposablePart"/> object.
+    /// </summary>
+    public class ContractBasedImportDefinition : ImportDefinition
+    {
+        // Unlike contract name, both metadata and required metadata has a sensible default; set it to an empty 
+        // enumerable, so that derived definitions only need to override ContractName by default.
+        private readonly IEnumerable<KeyValuePair<string, Type>> _requiredMetadata = Enumerable.Empty<KeyValuePair<string, Type>>();
+        private Expression<Func<ExportDefinition, bool>> _constraint;
+        private readonly CreationPolicy _requiredCreationPolicy = CreationPolicy.Any;
+        private readonly string _requiredTypeIdentity = null;
+        private bool _isRequiredMetadataValidated = false;
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ContractBasedImportDefinition"/> class.
+        /// </summary>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Derived types calling this constructor can optionally override the 
+        ///         <see cref="ImportDefinition.ContractName"/>, <see cref="RequiredTypeIdentity"/>,
+        ///         <see cref="RequiredMetadata"/>, <see cref="ImportDefinition.Cardinality"/>, 
+        ///         <see cref="ImportDefinition.IsPrerequisite"/>, <see cref="ImportDefinition.IsRecomposable"/> 
+        ///         and <see cref="RequiredCreationPolicy"/> properties.
+        ///     </note>
+        /// </remarks>
+        protected ContractBasedImportDefinition()
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ContractBasedImportDefinition"/> class 
+        ///     with the specified contract name, required metadataq, cardinality, value indicating 
+        ///     if the import definition is recomposable and a value indicating if the import definition 
+        ///     is a prerequisite.
+        /// </summary>
+        /// <param name="contractName">
+        ///     A <see cref="String"/> containing the contract name of the 
+        ///     <see cref="Export"/> required by the <see cref="ContractBasedImportDefinition"/>.
+        /// </param>
+        /// <param name="requiredTypeIdentity">
+        ///     The type identity of the export type expected. Use <see cref="AttributedModelServices.GetTypeIdentity(Type)"/>
+        ///     to generate a type identity for a given type. If no specific type is required pass <see langword="null"/>.
+        /// </param>
+        /// <param name="requiredMetadata">
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="String"/> objects containing
+        ///     the metadata names of the <see cref="Export"/> required by the 
+        ///     <see cref="ContractBasedImportDefinition"/>; or <see langword="null"/> to
+        ///     set the <see cref="RequiredMetadata"/> property to an empty <see cref="IEnumerable{T}"/>.
+        /// </param>
+        /// <param name="cardinality">
+        ///     One of the <see cref="ImportCardinality"/> values indicating the 
+        ///     cardinality of the <see cref="Export"/> objects required by the
+        ///     <see cref="ContractBasedImportDefinition"/>.
+        /// </param>
+        /// <param name="isRecomposable">
+        ///     <see langword="true"/> if the <see cref="ContractBasedImportDefinition"/> can be satisfied 
+        ///     multiple times throughout the lifetime of a <see cref="ComposablePart"/>, otherwise, 
+        ///     <see langword="false"/>.
+        /// </param>
+        /// <param name="isPrerequisite">
+        ///     <see langword="true"/> if the <see cref="ContractBasedImportDefinition"/> is required to be 
+        ///     satisfied before a <see cref="ComposablePart"/> can start producing exported 
+        ///     objects; otherwise, <see langword="false"/>.
+        /// </param>
+        /// <param name="requiredCreationPolicy">
+        ///     A value indicating that the importer requires a specific <see cref="CreationPolicy"/> for 
+        ///     the exports used to satisfy this import. If no specific <see cref="CreationPolicy"/> is needed
+        ///     pass the default <see cref="CreationPolicy.Any"/>.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="contractName"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="contractName"/> is an empty string ("").
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="requiredMetadata"/> contains an element that is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="cardinality"/> is not one of the <see cref="ImportCardinality"/> 
+        ///     values.
+        /// </exception>
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public ContractBasedImportDefinition(string contractName, string requiredTypeIdentity, IEnumerable<KeyValuePair<string, Type>> requiredMetadata, 
+            ImportCardinality cardinality, bool isRecomposable, bool isPrerequisite, CreationPolicy requiredCreationPolicy)
+            : this(contractName, requiredTypeIdentity, requiredMetadata, cardinality, isRecomposable, isPrerequisite, requiredCreationPolicy, MetadataServices.EmptyMetadata)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ContractBasedImportDefinition"/> class 
+        ///     with the specified contract name, required metadataq, cardinality, value indicating 
+        ///     if the import definition is recomposable and a value indicating if the import definition 
+        ///     is a prerequisite.
+        /// </summary>
+        /// <param name="contractName">
+        ///     A <see cref="String"/> containing the contract name of the 
+        ///     <see cref="Export"/> required by the <see cref="ContractBasedImportDefinition"/>.
+        /// </param>
+        /// <param name="requiredTypeIdentity">
+        ///     The type identity of the export type expected. Use <see cref="AttributedModelServices.GetTypeIdentity(Type)"/>
+        ///     to generate a type identity for a given type. If no specific type is required pass <see langword="null"/>.
+        /// </param>
+        /// <param name="requiredMetadata">
+        ///     An <see cref="IEnumerable{T}"/> of <see cref="String"/> objects containing
+        ///     the metadata names of the <see cref="Export"/> required by the 
+        ///     <see cref="ContractBasedImportDefinition"/>; or <see langword="null"/> to
+        ///     set the <see cref="RequiredMetadata"/> property to an empty <see cref="IEnumerable{T}"/>.
+        /// </param>
+        /// <param name="cardinality">
+        ///     One of the <see cref="ImportCardinality"/> values indicating the 
+        ///     cardinality of the <see cref="Export"/> objects required by the
+        ///     <see cref="ContractBasedImportDefinition"/>.
+        /// </param>
+        /// <param name="isRecomposable">
+        ///     <see langword="true"/> if the <see cref="ContractBasedImportDefinition"/> can be satisfied 
+        ///     multiple times throughout the lifetime of a <see cref="ComposablePart"/>, otherwise, 
+        ///     <see langword="false"/>.
+        /// </param>
+        /// <param name="isPrerequisite">
+        ///     <see langword="true"/> if the <see cref="ContractBasedImportDefinition"/> is required to be 
+        ///     satisfied before a <see cref="ComposablePart"/> can start producing exported 
+        ///     objects; otherwise, <see langword="false"/>.
+        /// </param>
+        /// <param name="requiredCreationPolicy">
+        ///     A value indicating that the importer requires a specific <see cref="CreationPolicy"/> for 
+        ///     the exports used to satisfy this import. If no specific <see cref="CreationPolicy"/> is needed
+        ///     pass the default <see cref="CreationPolicy.Any"/>.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="contractName"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="contractName"/> is an empty string ("").
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="requiredMetadata"/> contains an element that is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="cardinality"/> is not one of the <see cref="ImportCardinality"/> 
+        ///     values.
+        /// </exception>
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public ContractBasedImportDefinition(string contractName, string requiredTypeIdentity, IEnumerable<KeyValuePair<string, Type>> requiredMetadata,
+            ImportCardinality cardinality, bool isRecomposable, bool isPrerequisite, CreationPolicy requiredCreationPolicy, IDictionary<string, object> metadata)
+            : base(contractName, cardinality, isRecomposable, isPrerequisite, metadata)
+        {
+            Requires.NotNullOrEmpty(contractName, "contractName");
+
+            this._requiredTypeIdentity = requiredTypeIdentity;
+
+            if (requiredMetadata != null)
+            {
+                this._requiredMetadata = requiredMetadata;
+            }
+
+            this._requiredCreationPolicy = requiredCreationPolicy;
+        }
+
+        /// <summary>
+        ///     The type identity of the export type expected.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="string"/> that is generated by <see cref="AttributedModelServices.GetTypeIdentity(Type)"/>
+        ///     on the type that this import expects. If the value is <see langword="null"/> then this import
+        ///     doesn't expect a particular type.
+        /// </value>
+        public virtual string RequiredTypeIdentity
+        {
+            get { return this._requiredTypeIdentity; }
+        }
+
+        /// <summary>
+        ///     Gets the metadata names of the export required by the import definition.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IEnumerable{T}"/> of pairs of metadata keys and types of the <see cref="Export"/> required by the 
+        ///     <see cref="ContractBasedImportDefinition"/>. The default is an empty 
+        ///     <see cref="IEnumerable{T}"/>.
+        /// </value>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Overriders of this property should never return <see langword="null"/>
+        ///         or return an <see cref="IEnumerable{T}"/> that contains an element that is
+        ///         <see langword="null"/>. If the definition does not contain required metadata, 
+        ///         return an empty <see cref="IEnumerable{T}"/> instead.
+        ///     </note>
+        /// </remarks>
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public virtual IEnumerable<KeyValuePair<string, Type>> RequiredMetadata
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<IEnumerable<KeyValuePair<string, Type>>>() != null);
+                
+                // NOTE : unlike other arguments, we validate this one as late as possible, because its validation may lead to type loading
+                this.ValidateRequiredMetadata();
+
+                return this._requiredMetadata;
+            }
+        }
+
+        private void ValidateRequiredMetadata()
+        {
+            if (!this._isRequiredMetadataValidated)
+            {
+                foreach (KeyValuePair<string, Type> metadataItem in this._requiredMetadata)
+                {
+                    if ((metadataItem.Key == null) || (metadataItem.Value == null))
+                    {
+                        throw new InvalidOperationException(
+                            string.Format(CultureInfo.CurrentCulture, Strings.Argument_NullElement, "requiredMetadata"));
+                    }
+                }
+                this._isRequiredMetadataValidated = true;
+            }
+        }
+
+        /// <summary>
+        ///     Gets or sets a value indicating that the importer requires a specific 
+        ///     <see cref="CreationPolicy"/> for the exports used to satisfy this import. T
+        /// </summary>
+        /// <value>
+        ///     <see cref="CreationPolicy.Any"/> - default value, used if the importer doesn't 
+        ///         require a specific <see cref="CreationPolicy"/>.
+        /// 
+        ///     <see cref="CreationPolicy.Shared"/> - Requires that all exports used should be shared
+        ///         by everyone in the container.
+        /// 
+        ///     <see cref="CreationPolicy.NonShared"/> - Requires that all exports used should be 
+        ///         non-shared in a container and thus everyone gets their own instance.
+        /// </value>
+        public virtual CreationPolicy RequiredCreationPolicy
+        {
+            get { return this._requiredCreationPolicy; }
+        }
+
+        /// <summary>
+        ///     Gets an expression that defines conditions that must be matched for the import 
+        ///     described by the import definition to be satisfied.
+        /// </summary>
+        /// <returns>
+        ///     A <see cref="Expression{TDelegate}"/> containing a <see cref="Func{T, TResult}"/> 
+        ///     that defines the conditions that must be matched for the 
+        ///     <see cref="ImportDefinition"/> to be satisfied by an <see cref="Export"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <para>
+        ///         This property returns an expression that defines conditions based on the 
+        ///         <see cref="ImportDefinition.ContractName"/>, <see cref="RequiredTypeIdentity"/>, 
+        ///         <see cref="RequiredMetadata"/>, and <see cref="RequiredCreationPolicy"/>
+        ///         properties. 
+        ///     </para>
+        /// </remarks>
+        public override Expression<Func<ExportDefinition, bool>> Constraint
+        {   
+            get
+            {
+                if (this._constraint == null)
+                {
+                    this._constraint = ConstraintServices.CreateConstraint(this.ContractName, this.RequiredTypeIdentity, this.RequiredMetadata, this.RequiredCreationPolicy);
+                }
+
+                return this._constraint;
+            }
+        }
+
+        /// <summary>
+        ///     Executes an optimized version of the contraint given by the <see cref="Constraint"/> property
+        /// </summary>
+        /// <param name="exportDefinition">
+        ///     A definition for a <see cref="Export"/> used to determine if it satisfies the
+        ///     requirements for this <see cref="ImportDefinition"/>.
+        /// </param>
+        /// <returns>
+        ///     <see langword="True"/> if the <see cref="Export"/> satisfies the requirements for
+        ///     this <see cref="ImportDefinition"/>, otherwise returns <see langword="False"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Overrides of this method can provide a more optimized execution of the 
+        ///         <see cref="Constraint"/> property but the result should remain consistent.
+        ///     </note>
+        /// </remarks>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="exportDefinition"/> is <see langword="null"/>.
+        /// </exception>
+        public override bool IsConstraintSatisfiedBy(ExportDefinition exportDefinition)
+        {
+            Requires.NotNull(exportDefinition, "exportDefinition");
+
+            if (!StringComparers.ContractName.Equals(this.ContractName, exportDefinition.ContractName))
+            {
+                return false;
+            }
+
+            return MatchRequiredMatadata(exportDefinition);
+        }
+
+        private bool MatchRequiredMatadata(ExportDefinition definition)
+        {
+            if (!string.IsNullOrEmpty(this.RequiredTypeIdentity))
+            {
+                string exportTypeIdentity = definition.Metadata.GetValue<string>(CompositionConstants.ExportTypeIdentityMetadataName);
+
+                if (!StringComparers.ContractName.Equals(this.RequiredTypeIdentity, exportTypeIdentity))
+                {
+                    return false;
+                }
+            }
+
+            foreach (KeyValuePair<string, Type> metadataItem in this.RequiredMetadata)
+            {
+                string metadataKey = metadataItem.Key;
+                Type metadataValueType = metadataItem.Value;
+
+                object metadataValue = null;
+                if (!definition.Metadata.TryGetValue(metadataKey, out metadataValue))
+                {
+                    return false;
+                }
+
+                if (metadataValue != null)
+                {
+                    // the metadata value is not null, we can rely on IsInstanceOfType to do the right thing
+                    if (!metadataValueType.IsInstanceOfType(metadataValue))
+                    {
+                        return false;
+                    }
+                }
+                else
+                {
+                    // this is an unfortunate special case - typeof(object).IsInstanceofType(null) == false
+                    // basically nulls are not considered valid values for anything
+                    // We want them to match anything that is a reference type
+                    if (metadataValueType.IsValueType)
+                    {
+                        // this is a pretty expensive check, but we only invoke it when metadata values are null, which is very rare
+                        return false;
+                    }
+                }
+            }
+
+            if (this.RequiredCreationPolicy == CreationPolicy.Any)
+            {
+                return true;
+            }
+
+            CreationPolicy exportPolicy = definition.Metadata.GetValue<CreationPolicy>(CompositionConstants.PartCreationPolicyMetadataName);
+            return exportPolicy == CreationPolicy.Any ||
+                   exportPolicy == this.RequiredCreationPolicy;
+        }
+
+        public override string ToString()
+        {
+            var sb = new StringBuilder();
+
+            sb.Append(string.Format("\n\tContractName\t{0}", this.ContractName));
+            sb.Append(string.Format("\n\tRequiredTypeIdentity\t{0}", this.RequiredTypeIdentity));
+            if(this._requiredCreationPolicy != CreationPolicy.Any)
+            {
+                sb.Append(string.Format("\n\tRequiredCreationPolicy\t{0}", this.RequiredCreationPolicy));
+            }
+
+            if(this._requiredMetadata.Count() > 0)
+            {
+                sb.Append(string.Format("\n\tRequiredMetadata"));
+                foreach (KeyValuePair<string, Type> metadataItem in this._requiredMetadata)
+                {
+                    sb.Append(string.Format("\n\t\t{0}\t({1})", metadataItem.Key, metadataItem.Value));
+                }
+            }
+            return sb.ToString();
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/Export.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/Export.cs
new file mode 100644
index 00000000000..fdcdfe6f358
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/Export.cs
@@ -0,0 +1,253 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using Microsoft.Internal;
+using System.Threading;
+using System.Diagnostics.Contracts;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    /// <summary>
+    ///     Represents an export. That is, a type that is made up of a delay-created exported value 
+    ///     and metadata that describes that object.
+    /// </summary>
+    public class Export
+    {
+        private readonly ExportDefinition _definition;
+        private readonly Func<object> _exportedValueGetter;
+        private static readonly object _EmptyValue = new object();
+        private volatile object _exportedValue = Export._EmptyValue;
+        
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="Export"/> class.
+        /// </summary>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Derived types calling this constructor must override <see cref="Definition"/>
+        ///         and <see cref="GetExportedValueCore"/>.
+        ///     </note>
+        /// </remarks>
+        protected Export()
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="Export"/> class 
+        ///     with the specified contract name and exported value getter.
+        /// </summary>
+        /// <param name="contractName">
+        ///     A <see cref="String"/> containing the contract name of the 
+        ///     <see cref="Export"/>.
+        /// </param>
+        /// <param name="exportedValueGetter">
+        ///     A <see cref="Func{T}"/> that is called to create the exported value of the 
+        ///     <see cref="Export"/>. This allows the creation of the object to be delayed
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="contractName"/> is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="exportedValueGetter"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="contractName"/> is an empty string ("").
+        /// </exception>
+        public Export(string contractName, Func<object> exportedValueGetter)
+            : this(new ExportDefinition(contractName, (IDictionary<string, object>)null), exportedValueGetter)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="Export"/> class 
+        ///     with the specified contract name, metadata and exported value getter.
+        /// </summary>
+        /// <param name="contractName">
+        ///     A <see cref="String"/> containing the contract name of the 
+        ///     <see cref="Export"/>.
+        /// </param>
+        /// <param name="metadata">
+        ///     An <see cref="IDictionary{TKey, TValue}"/> containing the metadata of the 
+        ///     <see cref="Export"/>; or <see langword="null"/> to set the 
+        ///     <see cref="Metadata"/> property to an empty, read-only 
+        ///     <see cref="IDictionary{TKey, TValue}"/>.
+        /// </param>
+        /// <param name="exportedValueGetter">
+        ///     A <see cref="Func{T}"/> that is called to create the exported value of the 
+        ///     <see cref="Export"/>. This allows the creation of the object to be delayed.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="contractName"/> is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="exportedValueGetter"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="contractName"/> is an empty string ("").
+        /// </exception>
+        public Export(string contractName, IDictionary<string, object> metadata, Func<object> exportedValueGetter) 
+            : this(new ExportDefinition(contractName, metadata), exportedValueGetter)
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="Export"/> class 
+        ///     with the specified export definition and exported value getter.
+        /// </summary>
+        /// <param name="definition">
+        ///     An <see cref="ExportDefinition"/> that describes the contract that the 
+        ///     <see cref="Export"/> satisfies.
+        /// </param>
+        /// <param name="exportedValueGetter">
+        ///     A <see cref="Func{T}"/> that is called to create the exported value of the 
+        ///     <see cref="Export"/>. This allows the creation of the object to be delayed. 
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="definition"/> is <see langword="null"/>.
+        ///     <para>
+        ///         -or-
+        ///     </para>
+        ///     <paramref name="exportedValueGetter"/> is <see langword="null"/>.
+        /// </exception>
+        public Export(ExportDefinition definition, Func<object> exportedValueGetter)
+        {
+            Requires.NotNull(definition, "definition");
+            Requires.NotNull(exportedValueGetter, "exportedValueGetter");
+
+            this._definition = definition;
+            this._exportedValueGetter = exportedValueGetter;
+        }
+
+        /// <summary>
+        ///     Gets the definition that describes the contract that the export satisfies.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="ExportDefinition"/> that describes the contract that 
+        ///     the <see cref="Export"/> satisfies.
+        /// </value>
+        /// <exception cref="NotImplementedException">
+        ///     This property was not overridden by a derived class.
+        /// </exception>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Overriders of this property should never return
+        ///         <see langword="null"/>.
+        ///     </note>
+        /// </remarks>
+        public virtual ExportDefinition Definition
+        {
+            get 
+            {
+                Contract.Ensures(Contract.Result<ExportDefinition>() != null);
+                
+                if (_definition != null)
+                {
+                    return _definition;
+                }
+
+                throw ExceptionBuilder.CreateNotOverriddenByDerived("Definition");
+            }
+        }
+
+        /// <summary>
+        ///     Gets the metadata of the export.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IDictionary{TKey, TValue}"/> containing the metadata of the 
+        ///     <see cref="Export"/>.
+        /// </value>
+        /// <exception cref="NotImplementedException">
+        ///     The <see cref="Definition"/> property was not overridden by a derived class.
+        /// </exception>
+        /// <remarks>
+        ///     <para>
+        ///         This property returns the value of <see cref="ExportDefinition.Metadata"/>
+        ///         of the <see cref="Definition"/> property.
+        ///     </para>
+        /// </remarks>
+        public IDictionary<string, object> Metadata
+        {
+            get 
+            {
+                Contract.Ensures(Contract.Result<IDictionary<string, object>>() != null);
+
+                return Definition.Metadata; 
+            }        
+        }
+
+        /// <summary>
+        ///     Returns the exported value of the export.
+        /// </summary>
+        /// <returns>
+        ///     The exported <see cref="Object"/> of the <see cref="Export"/>.
+        /// </returns>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will 
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        /// <exception cref="CompositionContractMismatchException">
+        ///     The current instance is an instance of <see cref="Lazy{T}"/> and the underlying 
+        ///     exported value cannot be cast to <c>T</c>.
+        /// </exception>
+        /// <exception cref="NotImplementedException">
+        ///     The <see cref="GetExportedValueCore"/> method was not overridden by a derived class.
+        /// </exception>
+        public object Value
+        {
+            get
+            {
+                // NOTE : the logic below guarantees that the value will be set exactly once. It DOES NOT, however, guarantee that GetExportedValueCore() will be executed
+                // more than once, as locking would be required for that. The said locking is problematic, as we can't reliable call 3rd party code under a lock.
+                if (this._exportedValue == Export._EmptyValue)
+                {
+                    object exportedValue = this.GetExportedValueCore();
+
+                    // NOTE : According to http://msdn.microsoft.com/en-us/library/4bw5ewxy.aspx, the warning is bogus when used with Interlocked API.
+#pragma warning disable 420
+                    Interlocked.CompareExchange(ref this._exportedValue, exportedValue, Export._EmptyValue);
+#pragma warning restore 420
+                }
+
+                return this._exportedValue;
+            }
+        }
+
+        /// <summary>
+        ///     Returns the exported value of the export.
+        /// </summary>
+        /// <returns>
+        ///     The exported <see cref="Object"/> of the <see cref="Export"/>.
+        /// </returns>
+        /// <exception cref="CompositionException">
+        ///     An error occurred during composition. <see cref="CompositionException.Errors"/> will 
+        ///     contain a collection of errors that occurred.
+        /// </exception>
+        /// <exception cref="CompositionContractMismatchException">
+        ///     The current instance is an instance of <see cref="Lazy{T}"/> and the underlying 
+        ///     exported value cannot be cast to <c>T</c>.
+        /// </exception>
+        /// <exception cref="NotImplementedException">
+        ///     The method was not overridden by a derived class.
+        /// </exception>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Overriders of this method should never return
+        ///         <see langword="null"/>.
+        ///     </note>
+        /// </remarks>
+        [SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate")]
+        protected virtual object GetExportedValueCore()
+        {
+            if (this._exportedValueGetter != null)
+            {
+                return this._exportedValueGetter.Invoke();
+            }
+
+            throw ExceptionBuilder.CreateNotOverriddenByDerived("GetExportedValueCore");
+        }
+    }   
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ExportDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ExportDefinition.cs
new file mode 100644
index 00000000000..6c7d1b1ccb7
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ExportDefinition.cs
@@ -0,0 +1,139 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using Microsoft.Internal;
+using System.Diagnostics.Contracts;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    /// <summary>
+    ///     Describes the contract that an <see cref="Export"/> object satisfies.
+    /// </summary>
+    public class ExportDefinition
+    {
+        // Unlike contract name, metadata has a sensible default; set it to an empty bag, 
+        // so that derived definitions only need to override ContractName by default.
+        private readonly IDictionary<string, object> _metadata = MetadataServices.EmptyMetadata;
+        private readonly string _contractName;
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ExportDefinition"/> class.
+        /// </summary>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Derived types calling this constructor must override <see cref="ContractName"/>
+        ///         and optionally, <see cref="Metadata"/>. By default, <see cref="Metadata"/>
+        ///         returns an empty, read-only dictionary.
+        ///     </note>
+        /// </remarks>
+        protected ExportDefinition()
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ExportDefinition"/> class with 
+        ///     the specified contract name and metadata.
+        /// </summary>
+        /// <param name="contractName">
+        ///     A <see cref="String"/> containing the contract name of the 
+        ///     <see cref="ExportDefinition"/>.
+        /// </param>
+        /// <param name="metadata">
+        ///     An <see cref="IDictionary{TKey, TValue}"/> containing the metadata of the 
+        ///     <see cref="ExportDefinition"/>; or <see langword="null"/> to set the 
+        ///     <see cref="Metadata"/> property to an empty, read-only 
+        ///     <see cref="IDictionary{TKey, TValue}"/>.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="contractName"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="contractName"/> is an empty string ("").
+        /// </exception>
+        public ExportDefinition(string contractName, IDictionary<string, object> metadata)
+        {
+            Requires.NotNullOrEmpty(contractName, "contractName");
+
+            _contractName = contractName;
+
+            if (metadata != null)
+            {
+                _metadata = metadata.AsReadOnly();
+            }
+        }
+
+        /// <summary>
+        ///     Gets the contract name of the export definition.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="String"/> containing the contract name of the 
+        ///     <see cref="ExportDefinition"/>.
+        /// </value>
+        /// <exception cref="NotImplementedException">
+        ///     The property was not overridden by a derived class.
+        /// </exception>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Overriders of this property should never return <see langword="null"/> 
+        ///         or an empty string ("").
+        ///     </note>
+        /// </remarks>
+        public virtual string ContractName
+        {
+            get 
+            {
+                Contract.Ensures(!string.IsNullOrEmpty(Contract.Result<string>()));
+
+                if (_contractName != null)
+                {
+                    return _contractName;
+                }
+
+                throw ExceptionBuilder.CreateNotOverriddenByDerived("ContractName");
+            }
+        }
+
+        /// <summary>
+        ///     Gets the metadata of the export definition.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IDictionary{TKey, TValue}"/> containing the metadata of the 
+        ///     <see cref="ExportDefinition"/>. The default is an empty, read-only
+        ///     <see cref="IDictionary{TKey, TValue}"/>.
+        /// </value>
+        /// <remarks>
+        ///     <para>
+        ///         <note type="inheritinfo">
+        ///             Overriders of this property should return a read-only
+        ///             <see cref="IDictionary{TKey, TValue}"/> object with a case-sensitive, 
+        ///             non-linguistic comparer, such as <see cref="StringComparer.Ordinal"/>, 
+        ///             and should never return <see langword="null"/>.
+        ///             If the <see cref="ExportDefinition"/> does not contain metadata 
+        ///             return an empty <see cref="IDictionary{TKey, TValue}"/> instead.
+        ///         </note>
+        ///     </para>
+        /// </remarks>
+        public virtual IDictionary<string, object> Metadata
+        {
+            get 
+            {
+                Contract.Ensures(Contract.Result<IDictionary<string, object>>() != null);
+
+                return _metadata; 
+            }
+        }
+
+        /// <summary>
+        ///     Returns a string representation of the export definition.
+        /// </summary>
+        /// <returns>
+        ///     A <see cref="String"/> containing the value of the <see cref="ContractName"/> property.
+        /// </returns>
+        public override string ToString()
+        {
+            return this.ContractName;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ExportedDelegate.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ExportedDelegate.cs
new file mode 100644
index 00000000000..98c120987f9
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ExportedDelegate.cs
@@ -0,0 +1,58 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Reflection;
+using Microsoft.Internal;
+using System.Linq.Expressions;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    [SuppressMessage("Microsoft.Naming", "CA1711:IdentifiersShouldNotHaveIncorrectSuffix")]
+    public class ExportedDelegate
+    {
+        private object _instance;
+        private MethodInfo _method;
+
+        protected ExportedDelegate() { }
+
+#if FEATURE_CAS_APTCA
+        [System.Security.SecurityCritical]
+#endif //FEATURE_CAS_APTCA
+        public ExportedDelegate(object instance, MethodInfo method)
+        {
+            Requires.NotNull(method, "method");
+
+            this._instance = instance;
+            this._method = method;
+        }
+
+        public virtual Delegate CreateDelegate(Type delegateType) 
+        {
+            Requires.NotNull(delegateType, "delegateType");
+
+            if (delegateType == typeof(Delegate) || delegateType == typeof(MulticastDelegate))
+            {
+                delegateType = this.CreateStandardDelegateType();
+            }
+            
+            return Delegate.CreateDelegate(delegateType, this._instance, this._method, false);
+        }
+
+        private Type CreateStandardDelegateType()
+        {
+            ParameterInfo[] parameters = this._method.GetParameters();
+
+            // This array should contains a lit of all argument types, and the last one is the return type (could be void)
+            Type[] parameterTypes = new Type[parameters.Length + 1];
+            parameterTypes[parameters.Length] = this._method.ReturnType;
+            for (int i = 0; i < parameters.Length; i++ )
+            {
+                parameterTypes[i] = parameters[i].ParameterType;
+            }
+
+            return Expression.GetDelegateType(parameterTypes);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ICompositionElement.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ICompositionElement.cs
new file mode 100644
index 00000000000..42941dfc63d
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ICompositionElement.cs
@@ -0,0 +1,48 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Diagnostics.Contracts;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    /// <summary>
+    ///     Represents an element that participates in composition.
+    /// </summary>
+#if CONTRACTS_FULL
+    [ContractClass(typeof(ICompositionElementContract))]
+#endif
+    public interface ICompositionElement
+    {
+        /// <summary>
+        ///     Gets the display name of the composition element.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="String"/> containing a human-readable display name of the <see cref="ICompositionElement"/>.
+        /// </value>
+        /// <remarks>
+        ///     <note type="implementnotes">
+        ///         Implementors of this property should never return <see langword="null"/> or an empty 
+        ///         string ("").
+        ///     </note>
+        /// </remarks>
+        string DisplayName
+        {
+            get;
+        }
+
+        /// <summary>
+        ///     Gets the composition element from which the current composition element
+        ///     originated.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="ICompositionElement"/> from which the current 
+        ///     <see cref="ICompositionElement"/> originated, or <see langword="null"/> 
+        ///     if the <see cref="ICompositionElement"/> is the root composition element.
+        /// </value>
+        ICompositionElement Origin
+        {
+            get;
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/IPartCreatorImportDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/IPartCreatorImportDefinition.cs
new file mode 100644
index 00000000000..27ac0340a67
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/IPartCreatorImportDefinition.cs
@@ -0,0 +1,12 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    internal interface IPartCreatorImportDefinition
+    {
+        ContractBasedImportDefinition ProductImportDefinition { get; }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ImportCardinality.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ImportCardinality.cs
new file mode 100644
index 00000000000..5ce945f174d
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ImportCardinality.cs
@@ -0,0 +1,28 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    /// <summary>
+    ///     Indicates the cardinality of the <see cref="Export"/> objects required by an <see cref="ImportDefinition"/>.
+    /// </summary>
+    public enum ImportCardinality
+    {
+        /// <summary>
+        ///     Zero or one <see cref="Export"/> objects are required by an <see cref="ImportDefinition"/>.
+        /// </summary>
+        ZeroOrOne = 0,
+
+        /// <summary>
+        ///     Exactly one <see cref="Export"/> object is required by an <see cref="ImportDefinition"/>.
+        /// </summary>
+        ExactlyOne = 1,
+
+        /// <summary>
+        ///     Zero or more <see cref="Export"/> objects are required by an <see cref="ImportDefinition"/>.
+        /// </summary>
+        ZeroOrMore = 2,
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ImportDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ImportDefinition.cs
new file mode 100644
index 00000000000..a8e042b5921
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/ImportDefinition.cs
@@ -0,0 +1,291 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Linq.Expressions;
+using Microsoft.Internal;
+using System.Diagnostics.Contracts;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    /// <summary>
+    ///     Represents an import required by a <see cref="ComposablePart"/> object.
+    /// </summary>
+    public class ImportDefinition
+    {
+        internal static readonly string EmptyContractName = string.Empty;
+        private readonly Expression<Func<ExportDefinition, bool>> _constraint;
+        private readonly ImportCardinality _cardinality = ImportCardinality.ExactlyOne;
+        private readonly string _contractName = EmptyContractName;
+        private readonly bool _isRecomposable;
+        private readonly bool _isPrerequisite = true;
+        private Func<ExportDefinition, bool> _compiledConstraint;
+        private readonly IDictionary<string, object> _metadata = MetadataServices.EmptyMetadata;
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportDefinition"/> class.
+        /// </summary>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Derived types calling this constructor must override the <see cref="Constraint"/> 
+        ///         property, and optionally, the <see cref="Cardinality"/>, <see cref="IsPrerequisite"/> 
+        ///         and <see cref="IsRecomposable"/> 
+        ///         properties.
+        ///     </note>
+        /// </remarks>
+        protected ImportDefinition()
+        {
+        }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="ImportDefinition"/> class 
+        ///     with the specified constraint, cardinality, value indicating if the import 
+        ///     definition is recomposable and a value indicating if the import definition 
+        ///     is a prerequisite.
+        /// </summary>
+        /// <param name="constraint">
+        ///     A <see cref="Expression{TDelegate}"/> containing a <see cref="Func{T, TResult}"/> 
+        ///     that defines the conditions that must be matched for the <see cref="ImportDefinition"/> 
+        ///     to be satisfied by an <see cref="Export"/>.
+        /// </param>
+        /// <param name="contractName">
+        ///     The contract name of the export that this import is interested in. The contract name
+        ///     property is used as guidance and not automatically enforced in the constraint. If 
+        ///     the contract name is a required in the constraint then it should be added to the constraint
+        ///     by the caller of this constructor.
+        /// </param>
+        /// <param name="cardinality">
+        ///     One of the <see cref="ImportCardinality"/> values indicating the 
+        ///     cardinality of the <see cref="Export"/> objects required by the
+        ///     <see cref="ImportDefinition"/>.
+        /// </param>
+        /// <param name="isRecomposable">
+        ///     <see langword="true"/> if the <see cref="ImportDefinition"/> can be satisfied 
+        ///     multiple times throughout the lifetime of a <see cref="ComposablePart"/>, otherwise, 
+        ///     <see langword="false"/>.
+        /// </param>
+        /// <param name="isPrerequisite">
+        ///     <see langword="true"/> if the <see cref="ImportDefinition"/> is required to be 
+        ///     satisfied before a <see cref="ComposablePart"/> can start producing exported 
+        ///     objects; otherwise, <see langword="false"/>.
+        /// </param>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="constraint"/> is <see langword="null"/>.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        ///     <paramref name="cardinality"/> is not one of the <see cref="ImportCardinality"/> 
+        ///     values.
+        /// </exception>
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public ImportDefinition(Expression<Func<ExportDefinition, bool>> constraint, string contractName, ImportCardinality cardinality, bool isRecomposable, bool isPrerequisite)
+            : this(contractName, cardinality, isRecomposable, isPrerequisite, MetadataServices.EmptyMetadata)
+        {
+            Requires.NotNull(constraint, "constraint");
+
+            this._constraint = constraint;
+        }
+
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public ImportDefinition(Expression<Func<ExportDefinition, bool>> constraint, string contractName, ImportCardinality cardinality, bool isRecomposable, bool isPrerequisite, IDictionary<string, object> metadata)
+            : this(contractName, cardinality, isRecomposable, isPrerequisite, metadata)
+        {
+            Requires.NotNull(constraint, "constraint");
+
+            this._constraint = constraint;
+        }
+
+        internal ImportDefinition(string contractName, ImportCardinality cardinality, bool isRecomposable, bool isPrerequisite, IDictionary<string, object> metadata)
+        {
+            if (
+                (cardinality != ImportCardinality.ExactlyOne) &&
+                (cardinality != ImportCardinality.ZeroOrMore) &&
+                (cardinality != ImportCardinality.ZeroOrOne)
+                )
+            {
+                throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, Strings.ArgumentOutOfRange_InvalidEnum, "cardinality", cardinality, typeof(ImportCardinality).Name), "cardinality");
+            }
+
+            this._contractName = contractName ?? EmptyContractName;
+            this._cardinality = cardinality;
+            this._isRecomposable = isRecomposable;
+            this._isPrerequisite = isPrerequisite;
+
+            if (metadata != null)
+            {
+                this._metadata = metadata;
+            }
+        }
+
+        /// <summary>
+        ///     Gets the contract name of the export required by the import definition.
+        /// </summary>
+        /// <value>
+        ///     A <see cref="String"/> containing the contract name of the <see cref="Export"/> 
+        ///     required by the <see cref="ContractBasedImportDefinition"/>. This property should
+        ///     return <see cref="String.Empty"/> for imports that do not require a specific 
+        ///     contract name.
+        /// </value>
+        public virtual string ContractName
+        {
+            get 
+            {
+                Contract.Ensures(Contract.Result<string>() != null);
+
+                return this._contractName; 
+            }
+        }
+
+        /// <summary>
+        ///     Gets the metadata of the import definition.
+        /// </summary>
+        /// <value>
+        ///     An <see cref="IDictionary{TKey, TValue}"/> containing the metadata of the 
+        ///     <see cref="ExportDefinition"/>. The default is an empty, read-only
+        ///     <see cref="IDictionary{TKey, TValue}"/>.
+        /// </value>
+        /// <remarks>
+        ///     <para>
+        ///         <note type="inheritinfo">
+        ///             Overriders of this property should return a read-only
+        ///             <see cref="IDictionary{TKey, TValue}"/> object with a case-sensitive, 
+        ///             non-linguistic comparer, such as <see cref="StringComparer.Ordinal"/>, 
+        ///             and should never return <see langword="null"/>.
+        ///             If the <see cref="ImportDefinition"/> does not contain metadata 
+        ///             return an empty <see cref="IDictionary{TKey, TValue}"/> instead.
+        ///         </note>
+        ///     </para>
+        /// </remarks>
+        public virtual IDictionary<string, object> Metadata
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<IDictionary<string, object>>() != null);
+
+                return _metadata;
+            }
+        }
+
+        /// <summary>
+        ///     Gets the cardinality of the exports required by the import definition.
+        /// </summary>
+        /// <value>
+        ///     One of the <see cref="ImportCardinality"/> values indicating the 
+        ///     cardinality of the <see cref="Export"/> objects required by the
+        ///     <see cref="ImportDefinition"/>. The default is 
+        ///     <see cref="ImportCardinality.ExactlyOne"/>
+        /// </value>
+        public virtual ImportCardinality Cardinality
+        {
+            get { return this._cardinality; }
+        }
+
+        /// <summary>
+        ///     Gets an expression that defines conditions that must be matched for the import 
+        ///     described by the import definition to be satisfied.
+        /// </summary>
+        /// <returns>
+        ///     A <see cref="Expression{TDelegate}"/> containing a <see cref="Func{T, TResult}"/> 
+        ///     that defines the conditions that must be matched for the 
+        ///     <see cref="ImportDefinition"/> to be satisfied by an <see cref="Export"/>.
+        /// </returns>
+        /// <exception cref="NotImplementedException">
+        ///     The property was not overridden by a derived class.
+        /// </exception>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Overriders of this property should never return <see langword="null"/>.
+        ///     </note>
+        /// </remarks>
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public virtual Expression<Func<ExportDefinition, bool>> Constraint
+        {
+            get
+            {
+                Contract.Ensures(Contract.Result<Expression<Func<ExportDefinition, bool>>>() != null);
+                
+                if (this._constraint != null)
+                {
+                    return this._constraint;
+                }
+
+                throw ExceptionBuilder.CreateNotOverriddenByDerived("Constraint");
+            }
+        }
+
+        /// <summary>
+        ///     Gets a value indicating whether the import definition is required to be 
+        ///     satisfied before a part can start producing exported values.
+        /// </summary>
+        /// <value>
+        ///     <see langword="true"/> if the <see cref="ImportDefinition"/> is required to be 
+        ///     satisfied before a <see cref="ComposablePart"/> can start producing exported 
+        ///     objects; otherwise, <see langword="false"/>. The default is <see langword="true"/>.
+        /// </value>
+        public virtual bool IsPrerequisite
+        {
+            get { return this._isPrerequisite; }
+        }
+
+        /// <summary>
+        ///     Gets a value indicating whether the import definition can be satisfied multiple times.
+        /// </summary>
+        /// <value>
+        ///     <see langword="true"/> if the <see cref="ImportDefinition"/> can be satisfied 
+        ///     multiple times throughout the lifetime of a <see cref="ComposablePart"/>, otherwise, 
+        ///     <see langword="false"/>. The default is <see langword="false"/>.
+        /// </value>
+        public virtual bool IsRecomposable
+        {
+            get { return this._isRecomposable; }
+        }
+
+        /// <summary>
+        ///     Executes of the constraint provided by the <see cref="Constraint"/> property
+        ///     against a given <see cref="ExportDefinition"/> to determine if this 
+        ///     <see cref="ImportDefinition"/> can be satisfied by the given <see cref="Export"/>.
+        /// </summary>
+        /// <param name="exportDefinition">
+        ///     A definition for a <see cref="Export"/> used to determine if it satisfies the
+        ///     requirements for this <see cref="ImportDefinition"/>.
+        /// </param>
+        /// <returns>
+        ///     <see langword="True"/> if the <see cref="Export"/> satisfies the requirements for
+        ///     this <see cref="ImportDefinition"/>, otherwise returns <see langword="False"/>.
+        /// </returns>
+        /// <remarks>
+        ///     <note type="inheritinfo">
+        ///         Overrides of this method can provide a more optimized execution of the 
+        ///         <see cref="Constraint"/> property but the result should remain consistent.
+        ///     </note>
+        /// </remarks>
+        /// <exception cref="ArgumentNullException">
+        ///     <paramref name="exportDefinition"/> is <see langword="null"/>.
+        /// </exception>
+        public virtual bool IsConstraintSatisfiedBy(ExportDefinition exportDefinition)
+        {
+            Requires.NotNull(exportDefinition, "exportDefinition");
+
+            if (this._compiledConstraint == null)
+            {
+                this._compiledConstraint = this.Constraint.Compile();
+            }
+
+            return this._compiledConstraint.Invoke(exportDefinition);
+        }
+
+        /// <summary>
+        ///     Returns a string representation of the import definition.
+        /// </summary>
+        /// <returns>
+        ///     A <see cref="String"/> containing the value of the <see cref="Constraint"/> property.
+        /// </returns>
+        public override string ToString()
+        {
+            return this.Constraint.Body.ToString();
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/PrimitivesServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/PrimitivesServices.cs
new file mode 100644
index 00000000000..2cecbd86332
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/PrimitivesServices.cs
@@ -0,0 +1,100 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.ReflectionModel;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    internal static class PrimitivesServices
+    {
+        public static bool IsGeneric(this ComposablePartDefinition part)
+        {
+            return part.Metadata.GetValue<bool>(CompositionConstants.IsGenericPartMetadataName);
+        }
+
+        public static ImportDefinition GetProductImportDefinition(this ImportDefinition import)
+        {
+            IPartCreatorImportDefinition partCreatorDefinition = import as IPartCreatorImportDefinition;
+
+            if (partCreatorDefinition != null)
+            {
+                return partCreatorDefinition.ProductImportDefinition;
+            }
+            else
+            {
+                return import;
+            }
+        }
+
+        internal static IEnumerable<string> GetCandidateContractNames(this ImportDefinition import, ComposablePartDefinition part)
+        {
+            import = import.GetProductImportDefinition();
+            string contractName = import.ContractName;
+            string genericContractName = import.Metadata.GetValue<string>(CompositionConstants.GenericContractMetadataName);
+            int[] importParametersOrder = import.Metadata.GetValue<int[]>(CompositionConstants.GenericImportParametersOrderMetadataName);
+            if (importParametersOrder != null)
+            {
+                int partArity = part.Metadata.GetValue<int>(CompositionConstants.GenericPartArityMetadataName);
+                if (partArity > 0)
+                {
+                    contractName = GenericServices.GetGenericName(contractName, importParametersOrder, partArity);
+                }
+            }
+
+            yield return contractName;
+            if (!string.IsNullOrEmpty(genericContractName))
+            {
+                yield return genericContractName;
+            }
+        }
+
+
+        internal static bool IsImportDependentOnPart(this ImportDefinition import, ComposablePartDefinition part, ExportDefinition export, bool expandGenerics)
+        {
+            import = import.GetProductImportDefinition();
+            if (expandGenerics)
+            {
+                return part.GetExports(import).Any();
+            }
+            else
+            {
+                return TranslateImport(import, part).IsConstraintSatisfiedBy(export);
+            }
+        }
+
+        private static ImportDefinition TranslateImport(ImportDefinition import, ComposablePartDefinition part)
+        {
+            ContractBasedImportDefinition contractBasedImport = import as ContractBasedImportDefinition;
+            if (contractBasedImport == null)
+            {
+                return import;
+            }
+
+            int[] importParametersOrder = contractBasedImport.Metadata.GetValue<int[]>(CompositionConstants.GenericImportParametersOrderMetadataName);
+            if (importParametersOrder == null)
+            {
+                return import;
+            }
+
+            int partArity = part.Metadata.GetValue<int>(CompositionConstants.GenericPartArityMetadataName);
+            if (partArity == 0)
+            {
+                return import;
+            }
+
+            string contractName = GenericServices.GetGenericName(contractBasedImport.ContractName, importParametersOrder, partArity);
+            string requiredTypeIdentity = GenericServices.GetGenericName(contractBasedImport.RequiredTypeIdentity, importParametersOrder, partArity);
+            return new ContractBasedImportDefinition(
+                         contractName,
+                         requiredTypeIdentity,
+                         contractBasedImport.RequiredMetadata,
+                         contractBasedImport.Cardinality,
+                         contractBasedImport.IsRecomposable,
+                         false,
+                         contractBasedImport.RequiredCreationPolicy,
+                         contractBasedImport.Metadata);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/SerializableCompositionElement.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/SerializableCompositionElement.cs
new file mode 100644
index 00000000000..08c90076440
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/Primitives/SerializableCompositionElement.cs
@@ -0,0 +1,57 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.Primitives
+{
+    // As most objects that implement ICompositionElement (such as Export, ComposablePart, 
+    // ComposablePartCatalog, etc) are not serializable, this class is used as a serializable 
+    // placeholder for these types when ICompositionElement is used within serializable types,
+    // such as CompositionException, CompositionIssue, etc.
+    [Serializable]
+    internal class SerializableCompositionElement : ICompositionElement
+    {
+        private readonly string _displayName;
+        private readonly ICompositionElement _origin;
+
+        public SerializableCompositionElement(string displayName, ICompositionElement origin)
+        {
+#if FEATURE_SERIALIZATION
+            Assumes.IsTrue(origin == null || origin.GetType().IsSerializable);
+#endif
+            this._displayName = displayName ?? string.Empty;
+            this._origin = origin;
+        }
+
+        public string DisplayName
+        {
+            get { return this._displayName; }
+        }
+
+        public ICompositionElement Origin
+        {
+            get { return this._origin; }
+        }
+
+        public override string ToString()
+        {
+            return this.DisplayName;
+        }
+
+        public static ICompositionElement FromICompositionElement(ICompositionElement element)
+        {
+            if (element == null)
+            {   // Null is always serializable   
+
+                return null;
+            }
+
+            ICompositionElement origin = FromICompositionElement(element.Origin);
+
+            // Otherwise, we need to create a serializable wrapper
+            return new SerializableCompositionElement(element.DisplayName, origin);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/DisposableReflectionComposablePart.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/DisposableReflectionComposablePart.cs
new file mode 100644
index 00000000000..c883d1d6dbb
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/DisposableReflectionComposablePart.cs
@@ -0,0 +1,57 @@
+
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Linq;
+using System.Reflection;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal sealed class DisposableReflectionComposablePart : ReflectionComposablePart, IDisposable
+    {
+        private volatile int _isDisposed = 0;
+
+        public DisposableReflectionComposablePart(ReflectionComposablePartDefinition definition)
+            : base(definition)
+        {
+        }
+
+        protected override void ReleaseInstanceIfNecessary(object instance)
+        {
+            IDisposable disposable = instance as IDisposable;
+            if (disposable != null)
+            {
+                disposable.Dispose();
+            }
+        }
+
+        protected override void EnsureRunning()
+        {
+            base.EnsureRunning();
+            if (this._isDisposed == 1)
+            {
+                throw ExceptionBuilder.CreateObjectDisposed(this);
+            }
+        }
+
+        void IDisposable.Dispose()
+        {
+            // NOTE : According to http://msdn.microsoft.com/en-us/library/4bw5ewxy.aspx, the warning is bogus when used with Interlocked API.
+#pragma warning disable 420
+            if (Interlocked.CompareExchange(ref this._isDisposed, 1, 0) == 0)
+#pragma warning restore 420
+            {
+                this.ReleaseInstanceIfNecessary(this.CachedInstance);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ExportfactoryCreator.LifetimeContext.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ExportfactoryCreator.LifetimeContext.cs
new file mode 100644
index 00000000000..a1a2a85f8bd
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ExportfactoryCreator.LifetimeContext.cs
@@ -0,0 +1,80 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Linq;
+using System.Reflection;
+using System.Threading;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal sealed partial class ExportFactoryCreator
+    {
+        private class LifetimeContext
+        {
+            static Type[] types = { typeof(ComposablePartDefinition) };
+            public Func<ComposablePartDefinition, bool> CatalogFilter { get; private set; }
+
+            public void SetInstance(object instance)
+            {
+                Assumes.NotNull(instance);
+
+                var methodInfo = instance.GetType().GetMethod("IncludeInScopedCatalog", BindingFlags.NonPublic | BindingFlags.Instance, null, types, null);
+                CatalogFilter = (Func<ComposablePartDefinition, bool>)Delegate.CreateDelegate(typeof(Func<ComposablePartDefinition, bool>), instance, methodInfo);
+            }
+
+            public Tuple<T, Action> GetExportLifetimeContextFromExport<T>(Export export)
+            {
+                T exportedValue;
+                Action disposeAction;
+                IDisposable disposable = null;
+
+                CatalogExportProvider.ScopeFactoryExport scopeFactoryExport = export as CatalogExportProvider.ScopeFactoryExport;
+
+                if (scopeFactoryExport != null)
+                {
+                    // Scoped PartCreatorExport
+                    Export exportProduct = scopeFactoryExport.CreateExportProduct(CatalogFilter);
+                    exportedValue = ExportServices.GetCastedExportedValue<T>(exportProduct);
+                    disposable = exportProduct as IDisposable;
+                }
+                else
+                {
+                    CatalogExportProvider.FactoryExport factoryExport = export as CatalogExportProvider.FactoryExport;
+
+                    if (factoryExport != null)
+                    {
+                        // PartCreatorExport is the more optimized route
+                        Export exportProduct = factoryExport.CreateExportProduct();
+                        exportedValue = ExportServices.GetCastedExportedValue<T>(exportProduct);
+                        disposable = exportProduct as IDisposable;
+                    }
+                    else
+                    {
+                        // If it comes from somewhere else we walk through the ComposablePartDefinition
+                        var factoryPartDefinition = ExportServices.GetCastedExportedValue<ComposablePartDefinition>(export);
+                        var part = factoryPartDefinition.CreatePart();
+                        var exportDef = factoryPartDefinition.ExportDefinitions.Single();
+
+                        exportedValue = ExportServices.CastExportedValue<T>(part.ToElement(), part.GetExportedValue(exportDef));
+                        disposable = part as IDisposable;
+                    }
+                }
+
+                if (disposable != null)
+                {
+                    disposeAction = () => disposable.Dispose();
+                }
+                else
+                {
+                    disposeAction = () => { };
+                }
+
+                return new Tuple<T, Action>(exportedValue, disposeAction);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ExportfactoryCreator.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ExportfactoryCreator.cs
new file mode 100644
index 00000000000..35fa8516a78
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ExportfactoryCreator.cs
@@ -0,0 +1,79 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Linq;
+using System.Reflection;
+using System.Threading;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal sealed partial class ExportFactoryCreator
+    {
+        private static readonly MethodInfo _createStronglyTypedExportFactoryOfT = typeof(ExportFactoryCreator).GetMethod("CreateStronglyTypedExportFactoryOfT", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
+        private static readonly MethodInfo _createStronglyTypedExportFactoryOfTM = typeof(ExportFactoryCreator).GetMethod("CreateStronglyTypedExportFactoryOfTM", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
+
+        private Type    _exportFactoryType;
+
+        public ExportFactoryCreator(Type exportFactoryType)
+        {
+            Assumes.NotNull(exportFactoryType);
+
+            this._exportFactoryType = exportFactoryType;
+        }
+
+        public Func<Export, object> CreateStronglyTypedExportFactoryFactory(Type exportType, Type metadataViewType)
+        {
+            MethodInfo genericMethod = null;
+            if (metadataViewType == null)
+            {
+                 genericMethod = _createStronglyTypedExportFactoryOfT.MakeGenericMethod(exportType);
+            }
+            else
+            {
+                genericMethod = _createStronglyTypedExportFactoryOfTM.MakeGenericMethod(exportType, metadataViewType);
+            }
+
+            Assumes.NotNull(genericMethod);
+            Func<Export, object> exportFactoryFactory = (Func<Export, object>)Delegate.CreateDelegate(typeof(Func<Export, object>), this, genericMethod);
+            return (e) => exportFactoryFactory.Invoke(e);
+        }
+
+        private object CreateStronglyTypedExportFactoryOfT<T>(Export export)
+        {
+            Type[] typeArgs = { typeof(T) };
+            Type constructed = this._exportFactoryType.MakeGenericType(typeArgs);
+
+            var lifetimeContext = new LifetimeContext();
+
+            Func<Tuple<T, Action>> exportLifetimeContextCreator = () => lifetimeContext.GetExportLifetimeContextFromExport<T>(export);
+            object[] args = { exportLifetimeContextCreator };
+
+            var instance = Activator.CreateInstance(constructed, args);
+            lifetimeContext.SetInstance(instance);
+
+            return instance;
+        }
+
+        private object CreateStronglyTypedExportFactoryOfTM<T, M>(Export export)
+        {
+            Type[] typeArgs = { typeof(T), typeof(M) };
+            Type constructed = this._exportFactoryType.MakeGenericType(typeArgs);
+
+            var lifetimeContext = new LifetimeContext();
+
+            Func<Tuple<T, Action>> exportLifetimeContextCreator = () => lifetimeContext.GetExportLifetimeContextFromExport<T>(export);
+            var metadataView = AttributedModelServices.GetMetadataView<M>(export.Metadata);
+            object[] args = { exportLifetimeContextCreator, metadataView };
+
+            var instance =  Activator.CreateInstance(constructed, args);
+            lifetimeContext.SetInstance(instance);
+
+            return instance;
+        }
+
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ExportingMember.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ExportingMember.cs
new file mode 100644
index 00000000000..3276c7b47bf
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ExportingMember.cs
@@ -0,0 +1,103 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Globalization;
+using System.Reflection;
+using Microsoft.Internal;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class ExportingMember
+    {
+        private readonly ExportDefinition _definition;
+        private readonly ReflectionMember _member;
+        private object _cachedValue = null;
+        private volatile bool _isValueCached = false;
+
+        public ExportingMember(ExportDefinition definition, ReflectionMember member)
+        {
+            Assumes.NotNull(definition, member);
+
+            this._definition = definition;
+            this._member = member;
+        }
+
+        public bool RequiresInstance
+        {
+            get { return _member.RequiresInstance; }
+        }
+
+        public ExportDefinition Definition
+        {
+            get { return _definition; }
+        }
+
+        public object GetExportedValue(object instance, object @lock)
+        {
+            this.EnsureReadable();
+
+            if (!this._isValueCached)
+            {
+                object exportedValue;
+                try
+                {
+                    exportedValue = this._member.GetValue(instance);
+                }
+                catch (TargetInvocationException exception)
+                {   // Member threw an exception. Avoid letting this 
+                    // leak out as a 'raw' unhandled exception, instead,
+                    // we'll add some context and rethrow.
+
+                    throw new ComposablePartException(
+                        String.Format(CultureInfo.CurrentCulture,
+                            Strings.ReflectionModel_ExportThrewException,
+                            this._member.GetDisplayName()),
+                        Definition.ToElement(),
+                        exception.InnerException);
+                }
+                catch (TargetParameterCountException exception)
+                {
+                    // Exception was a TargetParameterCountException this occurs when we try to get an Indexer that has an Export
+                    // this is not supported in MEF currently.  Ideally we would validate against it, however, we already shipped
+                    // so we will turn it into a ComposablePartException instead, that they should already be prepared for
+                    throw new ComposablePartException(
+                        String.Format(CultureInfo.CurrentCulture,
+                        Strings.ExportNotValidOnIndexers,
+                        this._member.GetDisplayName()),
+                        Definition.ToElement(),
+                        exception.InnerException);
+                }
+
+                lock (@lock)
+                {
+                    if (!this._isValueCached)
+                    {
+                        this._cachedValue = exportedValue;
+                        Thread.MemoryBarrier();
+
+                        this._isValueCached = true;
+                    }
+                }
+            }
+
+            return this._cachedValue;
+        }
+
+        private void EnsureReadable()
+        {
+            if (!this._member.CanRead)
+            {   // Property does not have a getter
+
+                throw new ComposablePartException(
+                    String.Format(CultureInfo.CurrentCulture, 
+                        Strings.ReflectionModel_ExportNotReadable,
+                        this._member.GetDisplayName()),
+                    Definition.ToElement());
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/GenericServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/GenericServices.cs
new file mode 100644
index 00000000000..559b09e5146
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/GenericServices.cs
@@ -0,0 +1,216 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Linq;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Globalization;
+using System.Reflection;
+using Microsoft.Internal;
+using System.Threading;
+using System.Collections.Generic;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal static class GenericServices
+    {
+        internal static IList<Type> GetPureGenericParameters(this Type type)
+        {
+            Assumes.NotNull(type);
+
+            if (type.IsGenericType && type.ContainsGenericParameters)
+            {
+                List<Type> pureGenericParameters = new List<Type>();
+                TraverseGenericType(type, (Type t) =>
+                {
+                    if (t.IsGenericParameter)
+                    {
+                        pureGenericParameters.Add(t);
+                    }
+                });
+                return pureGenericParameters;
+            }
+            else
+            {
+                return Type.EmptyTypes;
+            }
+        }
+
+        internal static int GetPureGenericArity(this Type type)
+        {
+            Assumes.NotNull(type);
+
+            int genericArity = 0;
+            if (type.IsGenericType && type.ContainsGenericParameters)
+            {
+                List<Type> pureGenericParameters = new List<Type>();
+                TraverseGenericType(type, (Type t) =>
+                {
+                    if (t.IsGenericParameter)
+                    {
+                        genericArity++;
+                    }
+                });
+            }
+            return genericArity;
+        }
+
+
+
+        private static void TraverseGenericType(Type type, Action<Type> onType)
+        {
+            if (type.IsGenericType)
+            {
+                foreach(Type genericArgument in type.GetGenericArguments())
+                {
+                    TraverseGenericType(genericArgument, onType);
+                }
+            }
+            onType(type);
+        }
+
+        public static int[] GetGenericParametersOrder(Type type)
+        {
+            return type.GetPureGenericParameters().Select(parameter => parameter.GenericParameterPosition).ToArray();
+        }
+
+        public static string GetGenericName(string originalGenericName, int[] genericParametersOrder, int genericArity)
+        {
+            string[] genericFormatArgs = new string[genericArity];
+            for (int i = 0; i < genericParametersOrder.Length; i++)
+            {
+                genericFormatArgs[genericParametersOrder[i]] = string.Format(CultureInfo.InvariantCulture, "{{{0}}}", i);
+            }
+            return string.Format(CultureInfo.InvariantCulture, originalGenericName, genericFormatArgs);
+        }
+
+        public static T[] Reorder<T>(T[] original, int[] genericParametersOrder)
+        {
+            T[] genericSpecialization = new T[genericParametersOrder.Length];
+            for (int i = 0; i < genericParametersOrder.Length; i++)
+            {
+                genericSpecialization[i] = original[genericParametersOrder[i]];
+            }
+            return genericSpecialization;
+        }
+
+
+        public static IEnumerable<Type> CreateTypeSpecializations(this Type[] types, Type[] specializationTypes)
+        {
+            if (types == null)
+            {
+                return null;
+            }
+            else
+            {
+                return types.Select(type => type.CreateTypeSpecialization(specializationTypes));
+            }
+        }
+
+        public static Type CreateTypeSpecialization(this Type type, Type[] specializationTypes)
+        {
+            if (!type.ContainsGenericParameters)
+            {
+                return type;
+            }
+
+            if (type.IsGenericParameter)
+            {
+                // the only case when MakeGenericType won't work is when the 'type' represents a "naked" generic type
+                // in this case we simply grab the type with the proper index from the specializtion
+                return specializationTypes[type.GenericParameterPosition];
+            }
+            else
+            {
+                Type[] typeGenericArguments = type.GetGenericArguments();
+                Type[] subSpecialization = new Type[typeGenericArguments.Length];
+
+                for (int i = 0; i < typeGenericArguments.Length; i++)
+                {
+                    Type typeGenericArgument = typeGenericArguments[i];
+                    subSpecialization[i] = typeGenericArgument.IsGenericParameter ?
+                        specializationTypes[typeGenericArgument.GenericParameterPosition] : typeGenericArgument;
+
+                }
+
+                // and "close" the generic
+                return type.GetGenericTypeDefinition().MakeGenericType(subSpecialization);
+            }
+
+        }
+
+        public static bool CanSpecialize(Type type, IEnumerable<Type> constraints, GenericParameterAttributes attributes)
+        {
+            return CanSpecialize(type, constraints) && CanSpecialize(type, attributes);
+        }
+
+        public static bool CanSpecialize(Type type, IEnumerable<Type> constraintTypes)
+        {
+            if (constraintTypes == null)
+            {
+                return true;
+            }
+
+            // where T : IFoo
+            // a part of where T : struct is also handled here as T : ValueType
+            foreach (Type constraintType in constraintTypes)
+            {
+                if ((constraintType != null) && !constraintType.IsAssignableFrom(type))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        public static bool CanSpecialize(Type type, GenericParameterAttributes attributes)
+        {
+            if (attributes == GenericParameterAttributes.None)
+            {
+                return true;
+            }
+
+            // where T : class 
+            if ((attributes & GenericParameterAttributes.ReferenceTypeConstraint) != 0)
+            {
+                if (type.IsValueType)
+                {
+                    return false;
+                }
+            }
+
+            // where T : new
+            if ((attributes & GenericParameterAttributes.DefaultConstructorConstraint) != 0)
+            {
+                // value types always have default constructors
+                if (!type.IsValueType && (type.GetConstructor(Type.EmptyTypes) == null))
+                {
+                    return false;
+                }
+            }
+
+            // where T : struct 
+            if ((attributes & GenericParameterAttributes.NotNullableValueTypeConstraint) != 0)
+            {
+                // must be a value type
+                if (!type.IsValueType)
+                {
+                    return false;
+                }
+
+                // Make sure that the type is not nullable
+                // this is salways guaranteed in C#, but other languages may be different
+                if (Nullable.GetUnderlyingType(type) != null)
+                {
+                    return false;
+                }
+            }
+
+            // all other fals indicate variance and don't place any actual restrictions on the generic parameters
+            // but rather how they should be used by the compiler
+            return true;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/GenericSpecializationPartCreationInfo.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/GenericSpecializationPartCreationInfo.cs
new file mode 100644
index 00000000000..776e6218e02
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/GenericSpecializationPartCreationInfo.cs
@@ -0,0 +1,564 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Linq;
+using System.Reflection;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using System.Diagnostics.Contracts;
+using System.Threading;
+using System.ComponentModel.Composition.Hosting;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class GenericSpecializationPartCreationInfo : IReflectionPartCreationInfo
+    {
+        private readonly IReflectionPartCreationInfo _originalPartCreationInfo;
+        private readonly ReflectionComposablePartDefinition _originalPart;
+        private readonly Type[] _specialization;
+        private readonly string[] _specializationIdentities;
+        private IEnumerable<ExportDefinition> _exports;
+        private IEnumerable<ImportDefinition> _imports;
+        private readonly Lazy<Type> _lazyPartType;
+        private List<LazyMemberInfo> _members;
+        private List<Lazy<ParameterInfo>> _parameters;
+        private Dictionary<LazyMemberInfo, MemberInfo[]> _membersTable;
+        private Dictionary<Lazy<ParameterInfo>, ParameterInfo> _parametersTable;
+        private ConstructorInfo _constructor;
+        private object _lock = new object();
+
+        public GenericSpecializationPartCreationInfo(IReflectionPartCreationInfo originalPartCreationInfo, ReflectionComposablePartDefinition originalPart, Type[] specialization)
+        {
+            Assumes.NotNull(originalPartCreationInfo);
+            Assumes.NotNull(specialization);
+            Assumes.NotNull(originalPart);
+
+            this._originalPartCreationInfo = originalPartCreationInfo;
+            this._originalPart = originalPart;
+            this._specialization = specialization;
+            this._specializationIdentities = new string[this._specialization.Length];
+            for (int i = 0; i < this._specialization.Length; i++)
+            {
+                this._specializationIdentities[i] = AttributedModelServices.GetTypeIdentity(this._specialization[i]);
+            }
+            this._lazyPartType = new Lazy<Type>(
+                () => this._originalPartCreationInfo.GetPartType().MakeGenericType(specialization),
+                LazyThreadSafetyMode.PublicationOnly);
+
+        }
+
+        public ReflectionComposablePartDefinition OriginalPart
+        {
+            get
+            {
+                return this._originalPart;
+            }
+        }
+
+        public Type GetPartType()
+        {
+            return this._lazyPartType.Value;
+        }
+
+        public Lazy<Type> GetLazyPartType()
+        {
+            return this._lazyPartType;
+        }
+
+        public ConstructorInfo GetConstructor()
+        {
+            if (this._constructor == null)
+            {
+                ConstructorInfo genericConstuctor = this._originalPartCreationInfo.GetConstructor();
+                ConstructorInfo result = null;
+                if (genericConstuctor != null)
+                {
+                    foreach (ConstructorInfo constructor in this.GetPartType().GetConstructors(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance))
+                    {
+                        if (constructor.MetadataToken == genericConstuctor.MetadataToken)
+                        {
+                            result = constructor;
+                            break;
+                        }
+                    }
+                }
+
+                Thread.MemoryBarrier();
+                lock (this._lock)
+                {
+                    if (this._constructor == null)
+                    {
+                        this._constructor = result;
+                    }
+                }
+            }
+
+            return this._constructor;
+        }
+
+        public IDictionary<string, object> GetMetadata()
+        {
+            var originalMetadata = new Dictionary<string, object>(this._originalPartCreationInfo.GetMetadata(), StringComparers.MetadataKeyNames);
+            originalMetadata.Remove(CompositionConstants.IsGenericPartMetadataName);
+            originalMetadata.Remove(CompositionConstants.GenericPartArityMetadataName);
+            originalMetadata.Remove(CompositionConstants.GenericParameterConstraintsMetadataName);
+            originalMetadata.Remove(CompositionConstants.GenericParameterAttributesMetadataName);
+
+            return originalMetadata;
+        }
+
+        private MemberInfo[] GetAccessors(LazyMemberInfo originalLazyMember)
+        {
+            this.BuildTables();
+            Assumes.NotNull(this._membersTable);
+
+            return this._membersTable[originalLazyMember];
+        }
+
+        private ParameterInfo GetParameter(Lazy<ParameterInfo> originalParameter)
+        {
+            this.BuildTables();
+            Assumes.NotNull(this._parametersTable);
+
+            return this._parametersTable[originalParameter];
+        }
+
+        private void BuildTables()
+        {
+            if (this._membersTable != null)
+            {
+                return;
+            }
+
+            this.PopulateImportsAndExports();
+
+            List<LazyMemberInfo> members = null;
+            List<Lazy<ParameterInfo>> parameters = null;
+            lock (this._lock)
+            {
+                if (this._membersTable == null)
+                {
+                    members = this._members;
+                    parameters = this._parameters;
+
+                    Assumes.NotNull(members);
+                }
+            }
+
+            //
+            // Get all members that can be of interest and extract their MetadataTokens
+            //
+            Dictionary<LazyMemberInfo, MemberInfo[]> membersTable = this.BuildMembersTable(members);
+            Dictionary<Lazy<ParameterInfo>, ParameterInfo> parametersTable = this.BuildParametersTable(parameters);
+
+            lock (this._lock)
+            {
+                if (this._membersTable == null)
+                {
+                    this._membersTable = membersTable;
+                    this._parametersTable = parametersTable;
+
+                    Thread.MemoryBarrier();
+
+                    this._parameters = null;
+                    this._members = null;
+                }
+            }
+        }
+
+
+        private Dictionary<LazyMemberInfo, MemberInfo[]> BuildMembersTable(List<LazyMemberInfo> members)
+        {
+            Assumes.NotNull(members);
+
+            Dictionary<LazyMemberInfo, MemberInfo[]> membersTable = new Dictionary<LazyMemberInfo, MemberInfo[]>();
+            Dictionary<int, MemberInfo> specializedPartMembers = new Dictionary<int, MemberInfo>();
+
+            Type closedGenericPartType = this.GetPartType();
+
+            specializedPartMembers[closedGenericPartType.MetadataToken] = closedGenericPartType;
+            foreach (MethodInfo method in closedGenericPartType.GetAllMethods())
+            {
+                specializedPartMembers[method.MetadataToken] = method;
+            }
+
+            foreach (FieldInfo field in closedGenericPartType.GetAllFields())
+            {
+                specializedPartMembers[field.MetadataToken] = field;
+            }
+
+            //
+            // Now go through the members table and resolve them into the new closed type based on the tokens
+            //
+            foreach (LazyMemberInfo lazyMemberInfo in members)
+            {
+                MemberInfo[] genericAccessors = lazyMemberInfo.GetAccessors();
+                MemberInfo[] accessors = new MemberInfo[genericAccessors.Length];
+
+                for (int i = 0; i < genericAccessors.Length; i++)
+                {
+                    // GENTODO - error case? Very unlikely, but still?
+                    accessors[i] = (genericAccessors[i] != null) ? specializedPartMembers[genericAccessors[i].MetadataToken] : null;
+                }
+
+                membersTable[lazyMemberInfo] = accessors;
+            }
+
+            return membersTable;
+        }
+
+        private Dictionary<Lazy<ParameterInfo>, ParameterInfo> BuildParametersTable(List<Lazy<ParameterInfo>> parameters)
+        {
+            if (parameters != null)
+            {
+                Dictionary<Lazy<ParameterInfo>, ParameterInfo> parametersTable = new Dictionary<Lazy<ParameterInfo>, ParameterInfo>();
+                // GENTODO - error case
+                ParameterInfo[] constructorParameters = this.GetConstructor().GetParameters();
+                foreach (var lazyParameter in parameters)
+                {
+                    parametersTable[lazyParameter] = constructorParameters[lazyParameter.Value.Position];
+                }
+                return parametersTable;
+            }
+            else
+            {
+                return null;
+            }
+
+        }
+
+
+        private List<ImportDefinition> PopulateImports(List<LazyMemberInfo> members, List<Lazy<ParameterInfo>> parameters)
+        {
+            List<ImportDefinition> imports = new List<ImportDefinition>();
+
+            foreach (ImportDefinition originalImport in this._originalPartCreationInfo.GetImports())
+            {
+                ReflectionImportDefinition reflectionImport = originalImport as ReflectionImportDefinition;
+                if (reflectionImport == null)
+                {
+                    // we always ignore these
+                    continue;
+                }
+
+                imports.Add(this.TranslateImport(reflectionImport, members, parameters));
+            }
+
+            return imports;
+        }
+
+
+        private ImportDefinition TranslateImport(ReflectionImportDefinition reflectionImport, List<LazyMemberInfo> members, List<Lazy<ParameterInfo>> parameters)
+        {
+            bool isExportFactory = false;
+            ContractBasedImportDefinition productImport = reflectionImport;
+
+            IPartCreatorImportDefinition exportFactoryImportDefinition = reflectionImport as IPartCreatorImportDefinition;
+            if (exportFactoryImportDefinition != null)
+            {
+                productImport = exportFactoryImportDefinition.ProductImportDefinition;
+                isExportFactory = true;
+            }
+
+            string contractName = this.Translate(productImport.ContractName);
+            string requiredTypeIdentity = this.Translate(productImport.RequiredTypeIdentity);
+            IDictionary<string, object> metadata = this.TranslateImportMetadata(productImport);
+            
+            ReflectionMemberImportDefinition memberImport = reflectionImport as ReflectionMemberImportDefinition;
+            ImportDefinition import = null;
+            if (memberImport != null)
+            {
+                LazyMemberInfo lazyMember = memberImport.ImportingLazyMember;
+                LazyMemberInfo importingMember = new LazyMemberInfo(lazyMember.MemberType, () => GetAccessors(lazyMember));
+
+                if (isExportFactory)
+                {
+                    import = new PartCreatorMemberImportDefinition(
+                        importingMember,
+                        ((ICompositionElement)memberImport).Origin,
+                        new ContractBasedImportDefinition(
+                            contractName,
+                            requiredTypeIdentity,
+                            productImport.RequiredMetadata,
+                            productImport.Cardinality,
+                            productImport.IsRecomposable,
+                            false,
+                            CreationPolicy.NonShared,
+                            metadata));
+                }
+                else
+                {
+                    import = new ReflectionMemberImportDefinition(
+                         importingMember,
+                         contractName,
+                         requiredTypeIdentity,
+                         productImport.RequiredMetadata,
+                         productImport.Cardinality,
+                         productImport.IsRecomposable,
+                         false,
+                         productImport.RequiredCreationPolicy,
+                         metadata,
+                         ((ICompositionElement)memberImport).Origin);
+                }
+
+                members.Add(lazyMember);
+            }
+            else
+            {
+                ReflectionParameterImportDefinition parameterImport = reflectionImport as ReflectionParameterImportDefinition;
+                Assumes.NotNull(parameterImport);
+
+                Lazy<ParameterInfo> lazyParameter = parameterImport.ImportingLazyParameter;
+                Lazy<ParameterInfo> parameter = new Lazy<ParameterInfo>(() => GetParameter(lazyParameter));
+
+                if (isExportFactory)
+                {
+                    import = new PartCreatorParameterImportDefinition(
+                            parameter,
+                            ((ICompositionElement)parameterImport).Origin,
+                            new ContractBasedImportDefinition(
+                                contractName,
+                                requiredTypeIdentity,
+                                productImport.RequiredMetadata,
+                                productImport.Cardinality,
+                                false,
+                                true,
+                                CreationPolicy.NonShared,
+                                metadata));
+                }
+                else
+                {
+                    import = new ReflectionParameterImportDefinition(
+                         parameter,
+                         contractName,
+                         requiredTypeIdentity,
+                         productImport.RequiredMetadata,
+                         productImport.Cardinality,
+                         productImport.RequiredCreationPolicy,
+                         metadata,
+                         ((ICompositionElement)parameterImport).Origin);
+                }
+
+                parameters.Add(lazyParameter);
+            }
+
+            return import;
+        }
+
+        private List<ExportDefinition> PopulateExports(List<LazyMemberInfo> members)
+        {
+            List<ExportDefinition> exports = new List<ExportDefinition>();
+
+            foreach (ExportDefinition originalExport in this._originalPartCreationInfo.GetExports())
+            {
+                ReflectionMemberExportDefinition reflectionExport = originalExport as ReflectionMemberExportDefinition;
+                if (reflectionExport == null)
+                {
+                    // we always ignore these
+                    continue;
+                }
+
+                exports.Add(this.TranslateExpot(reflectionExport, members));
+            }
+
+            return exports;
+        }
+
+        public ExportDefinition TranslateExpot(ReflectionMemberExportDefinition reflectionExport, List<LazyMemberInfo> members)
+        {
+            ExportDefinition export = null;
+            LazyMemberInfo lazyMember = reflectionExport.ExportingLazyMember;
+            var capturedLazyMember = lazyMember;
+            var capturedReflectionExport = reflectionExport;
+
+            string contractName = this.Translate(reflectionExport.ContractName, reflectionExport.Metadata.GetValue<int[]>(CompositionConstants.GenericExportParametersOrderMetadataName));
+
+            LazyMemberInfo exportingMember = new LazyMemberInfo(capturedLazyMember.MemberType, () => GetAccessors(capturedLazyMember));
+            Lazy<IDictionary<string, object>> lazyMetadata = new Lazy<IDictionary<string, object>>(() => this.TranslateExportMetadata(capturedReflectionExport));
+
+
+
+            export = new ReflectionMemberExportDefinition(
+                exportingMember,
+                new LazyExportDefinition(contractName, lazyMetadata),
+                ((ICompositionElement)reflectionExport).Origin);
+
+            members.Add(capturedLazyMember);
+
+            return export;
+        }
+
+        private string Translate(string originalValue, int[] genericParametersOrder)
+        {
+            if (genericParametersOrder != null)
+            {
+                string[] specializationIdentities = GenericServices.Reorder(this._specializationIdentities, genericParametersOrder);
+                return string.Format(CultureInfo.InvariantCulture, originalValue, specializationIdentities);
+            }
+            else
+            {
+                return Translate(originalValue);
+            }
+        }
+
+        private string Translate(string originalValue)
+        {
+            return string.Format(CultureInfo.InvariantCulture, originalValue, this._specializationIdentities);
+        }
+
+        private IDictionary<string, object> TranslateImportMetadata(ContractBasedImportDefinition originalImport)
+        {
+            int[] importParametersOrder = originalImport.Metadata.GetValue<int[]>(CompositionConstants.GenericImportParametersOrderMetadataName);
+            if (importParametersOrder != null)
+            {
+                Dictionary<string, object> metadata = new Dictionary<string, object>(originalImport.Metadata, StringComparers.MetadataKeyNames);
+
+                // Get the newly re-qualified name of the generic contract and the subset of applicable types from the specialization
+                metadata[CompositionConstants.GenericContractMetadataName] = GenericServices.GetGenericName(originalImport.ContractName, importParametersOrder, this._specialization.Length);
+                metadata[CompositionConstants.GenericParametersMetadataName] = GenericServices.Reorder(this._specialization, importParametersOrder);
+                metadata.Remove(CompositionConstants.GenericImportParametersOrderMetadataName);
+
+                return metadata.AsReadOnly();
+            }
+            else
+            {
+                return originalImport.Metadata;
+            }
+        }
+
+        private IDictionary<string, object> TranslateExportMetadata(ReflectionMemberExportDefinition originalExport)
+        {
+            Dictionary<string, object> metadata = new Dictionary<string, object>(originalExport.Metadata, StringComparers.MetadataKeyNames);
+
+            string exportTypeIdentity = originalExport.Metadata.GetValue<string>(CompositionConstants.ExportTypeIdentityMetadataName);
+            if (!string.IsNullOrEmpty(exportTypeIdentity))
+            {
+                metadata[CompositionConstants.ExportTypeIdentityMetadataName] = this.Translate(exportTypeIdentity, originalExport.Metadata.GetValue<int[]>(CompositionConstants.GenericExportParametersOrderMetadataName));
+            }
+            metadata.Remove(CompositionConstants.GenericExportParametersOrderMetadataName);
+
+            return metadata;
+        }
+
+        private void PopulateImportsAndExports()
+        {
+            if ((this._exports == null) || (this._imports == null))
+            {
+                List<LazyMemberInfo> members = new List<LazyMemberInfo>();
+                List<Lazy<ParameterInfo>> parameters = new List<Lazy<ParameterInfo>>();
+
+                // we are very careful to not call any 3rd party code in either of these
+                var exports = this.PopulateExports(members);
+                var imports = this.PopulateImports(members, parameters);
+                Thread.MemoryBarrier();
+
+                lock (this._lock)
+                {
+                    if ((this._exports == null) || (this._imports == null))
+                    {
+                        this._members = members;
+                        if (parameters.Count > 0)
+                        {
+                            this._parameters = parameters;
+                        }
+
+                        this._exports = exports;
+                        this._imports = imports;
+                    }
+                }
+            }
+        }
+
+        public IEnumerable<ExportDefinition> GetExports()
+        {
+            this.PopulateImportsAndExports();
+            return this._exports;
+        }
+
+
+        public IEnumerable<ImportDefinition> GetImports()
+        {
+            this.PopulateImportsAndExports();
+            return this._imports;
+        }
+
+        public bool IsDisposalRequired
+        {
+            get { return this._originalPartCreationInfo.IsDisposalRequired; }
+        }
+
+        public string DisplayName
+        {
+            get { return this.Translate(this._originalPartCreationInfo.DisplayName); }
+        }
+
+        public ICompositionElement Origin
+        {
+            get { return this._originalPartCreationInfo.Origin; }
+        }
+
+        public override bool Equals(object obj)
+        {
+            GenericSpecializationPartCreationInfo that = obj as GenericSpecializationPartCreationInfo;
+            if (that == null)
+            {
+                return false;
+            }
+
+            return (this._originalPartCreationInfo.Equals(that._originalPartCreationInfo)) &&
+                (this._specialization.IsArrayEqual(that._specialization));
+        }
+
+        public override int GetHashCode()
+        {
+            return this._originalPartCreationInfo.GetHashCode();
+        }
+
+        public static bool CanSpecialize(IDictionary<string, object> partMetadata, Type[] specialization)
+        {
+            int partArity = partMetadata.GetValue<int>(CompositionConstants.GenericPartArityMetadataName);
+
+            if (partArity != specialization.Length)
+            {
+                return false;
+            }
+
+            object[] genericParameterConstraints = partMetadata.GetValue<object[]>(CompositionConstants.GenericParameterConstraintsMetadataName);
+            GenericParameterAttributes[] genericParameterAttributes = partMetadata.GetValue<GenericParameterAttributes[]>(CompositionConstants.GenericParameterAttributesMetadataName);
+
+            // if no constraints and attributes been specifed, anything can be created
+            if ((genericParameterConstraints == null) && (genericParameterAttributes == null))
+            {
+                return true;
+            }
+
+            if ((genericParameterConstraints != null) && (genericParameterConstraints.Length != partArity))
+            {
+                return false;
+            }
+
+            if ((genericParameterAttributes != null) && (genericParameterAttributes.Length != partArity))
+            {
+                return false;
+            }
+
+            for (int i = 0; i < partArity; i++)
+            {
+                if (!GenericServices.CanSpecialize(
+                    specialization[i],
+                    (genericParameterConstraints[i] as Type[]).CreateTypeSpecializations(specialization),
+                    genericParameterAttributes[i]))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/IReflectionPartCreationInfo.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/IReflectionPartCreationInfo.cs
new file mode 100644
index 00000000000..fa436109b91
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/IReflectionPartCreationInfo.cs
@@ -0,0 +1,22 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Reflection;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal interface IReflectionPartCreationInfo : ICompositionElement
+    {
+        Type GetPartType();
+        Lazy<Type> GetLazyPartType();
+        ConstructorInfo GetConstructor();
+        IDictionary<string, object> GetMetadata();
+        IEnumerable<ExportDefinition> GetExports();
+        IEnumerable<ImportDefinition> GetImports();
+        bool IsDisposalRequired { get; }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportType.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportType.cs
new file mode 100644
index 00000000000..7f085b919b5
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportType.cs
@@ -0,0 +1,174 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Primitives;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using System.Reflection;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    // Describes the import type of a Reflection-based import definition
+    internal class ImportType
+    {
+        private static readonly Type LazyOfTType = typeof(Lazy<>);
+        private static readonly Type LazyOfTMType = typeof(Lazy<,>);
+        private static readonly Type ExportFactoryOfTType = typeof(ExportFactory<>);
+        private static readonly Type ExportFactoryOfTMType = typeof(ExportFactory<,>);
+
+        private readonly Type _type;
+        private readonly bool _isAssignableCollectionType;
+        private readonly Type _contractType;
+        private Func<Export, object> _castSingleValue;
+        private bool _isOpenGeneric = false;
+
+        public ImportType(Type type, ImportCardinality cardinality)
+        {
+            Assumes.NotNull(type);
+
+            this._type = type;
+            this._contractType = type;
+
+            if (cardinality == ImportCardinality.ZeroOrMore)
+            {
+                this._isAssignableCollectionType = IsTypeAssignableCollectionType(type);
+                this._contractType = CheckForCollection(type);
+            }
+
+            this._isOpenGeneric = type.ContainsGenericParameters;
+            this._contractType = CheckForLazyAndPartCreator(this._contractType);
+        }
+
+        public bool IsAssignableCollectionType
+        {
+            get { return this._isAssignableCollectionType; }
+        }
+
+        public Type ElementType { get; private set; }
+
+        public Type ActualType
+        {
+            get { return this._type; }
+        }
+
+        public bool IsPartCreator { get; private set; }
+
+        public Type ContractType { get { return this._contractType; } }
+
+        public Func<Export, object> CastExport
+        {
+            get
+            {
+                Assumes.IsTrue(!this._isOpenGeneric);
+                return this._castSingleValue;
+            }
+        }
+
+        public Type MetadataViewType { get; private set; }
+
+        private Type CheckForCollection(Type type)
+        {
+            this.ElementType = CollectionServices.GetEnumerableElementType(type);
+            if (this.ElementType != null)
+            {
+                return this.ElementType;
+            }
+            return type;
+        }
+
+        private static bool IsGenericDescendentOf(Type type, Type baseGenericTypeDefinition)
+        {
+            if (type == typeof(object) || type == null)
+            {
+                return false;
+            }
+
+            if (type.IsGenericType && type.GetGenericTypeDefinition() == baseGenericTypeDefinition)
+            {
+                    return true;
+            }
+
+            return IsGenericDescendentOf(type.BaseType, baseGenericTypeDefinition);
+        }
+
+
+        public static bool IsDescendentOf(Type type, Type baseType)
+        {
+            Assumes.NotNull(type);
+            Assumes.NotNull(baseType);
+
+            if (!baseType.IsGenericTypeDefinition)
+            {
+                return baseType.IsAssignableFrom(type);
+            }
+
+            return IsGenericDescendentOf(type, baseType.GetGenericTypeDefinition());
+        }
+
+        private Type CheckForLazyAndPartCreator(Type type)
+        {
+            if (type.IsGenericType)
+            {
+                Type genericType = type.GetGenericTypeDefinition().UnderlyingSystemType;
+                Type[] arguments = type.GetGenericArguments();
+
+                if (genericType == LazyOfTType)
+                {
+                    if (!_isOpenGeneric)
+                    {
+                        this._castSingleValue = ExportServices.CreateStronglyTypedLazyFactory(arguments[0].UnderlyingSystemType, null);
+                    }
+                    return arguments[0];
+                }
+
+                if (genericType == LazyOfTMType)
+                {
+                    this.MetadataViewType = arguments[1];
+                    if (!_isOpenGeneric)
+                    {
+                        this._castSingleValue = ExportServices.CreateStronglyTypedLazyFactory(arguments[0].UnderlyingSystemType, arguments[1].UnderlyingSystemType);
+                    }
+                    return arguments[0];
+                }
+
+                if(genericType != null && IsDescendentOf(genericType, ExportFactoryOfTType))
+                {
+                    this.IsPartCreator = true;
+                    if (arguments.Length == 1)
+                    {
+                        if (!_isOpenGeneric)
+                        {
+                            this._castSingleValue = new ExportFactoryCreator(genericType).CreateStronglyTypedExportFactoryFactory(arguments[0].UnderlyingSystemType, null);
+                        }
+                    }
+                    else if (arguments.Length == 2)
+                    {
+                        if (!_isOpenGeneric)
+                        {
+                            this._castSingleValue = new ExportFactoryCreator(genericType).CreateStronglyTypedExportFactoryFactory(arguments[0].UnderlyingSystemType, arguments[1].UnderlyingSystemType);
+                        }
+                        this.MetadataViewType = arguments[1];
+                    }
+                    else
+                    {
+                        throw ExceptionBuilder.ExportFactory_TooManyGenericParameters(genericType.FullName);
+                    }
+                    return arguments[0];
+                }
+            }
+
+            return type;
+        }
+
+        private static bool IsTypeAssignableCollectionType(Type type)
+        {
+            if (type.IsArray || CollectionServices.IsEnumerableOfT(type))
+            {
+                return true;
+            }
+
+            return false;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportingItem.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportingItem.cs
new file mode 100644
index 00000000000..ca245fd315c
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportingItem.cs
@@ -0,0 +1,115 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Globalization;
+using System.Linq;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal abstract class ImportingItem
+    {
+        private readonly ContractBasedImportDefinition _definition;
+        private readonly ImportType _importType;
+
+        protected ImportingItem(ContractBasedImportDefinition definition, ImportType importType)
+        {
+            Assumes.NotNull(definition);
+
+            this._definition = definition;
+            this._importType = importType;
+        }
+
+        public ContractBasedImportDefinition Definition
+        {
+            get { return this._definition; }
+        }
+
+        public ImportType ImportType
+        {
+            get { return this._importType; }
+        }
+
+        public object CastExportsToImportType(Export[] exports)
+        {
+            if (this.Definition.Cardinality == ImportCardinality.ZeroOrMore)
+            {
+                return CastExportsToCollectionImportType(exports);
+            }
+            else
+            {
+                return CastExportsToSingleImportType(exports);
+            }
+        }
+
+        private object CastExportsToCollectionImportType(Export[] exports)
+        {
+            Assumes.NotNull(exports);
+
+            // Element type could be null if the actually import type of the member is not a collection
+            // This particular case will end up failing when we set the member.
+            Type elementType = this.ImportType.ElementType ?? typeof(object);
+
+            Array array = Array.CreateInstance(elementType, exports.Length);
+
+            for (int i = 0; i < array.Length; i++)
+            {
+                object value = CastSingleExportToImportType(elementType, exports[i]);
+
+                array.SetValue(value, i);
+            }
+
+            return array;
+        }
+
+        private object CastExportsToSingleImportType(Export[] exports)
+        {
+            Assumes.NotNull(exports);
+            Assumes.IsTrue(exports.Length < 2);
+
+            if (exports.Length == 0)
+            {   
+                return null;
+            }
+
+            return CastSingleExportToImportType(this.ImportType.ActualType, exports[0]);
+        }
+
+        private object CastSingleExportToImportType(Type type, Export export)
+        {
+            if (this.ImportType.CastExport != null)
+            {
+                return this.ImportType.CastExport(export);
+            }
+
+            return Cast(type, export);
+        }
+
+        private object Cast(Type type, Export export)
+        {
+            // TODO: Need to catch CompositionException to provide
+            // additional information about what member we're setting
+            // and the current dependency graph.
+            object value = export.Value;
+
+            object result;
+            if (!ContractServices.TryCast(type, value, out result))
+            {
+                throw new ComposablePartException(
+                    String.Format(CultureInfo.CurrentCulture,
+                        Strings.ReflectionModel_ImportNotAssignableFromExport,
+                        export.ToElement().DisplayName,
+                        type.FullName),
+                    this.Definition.ToElement());
+            }
+
+            return result;
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportingMember.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportingMember.cs
new file mode 100644
index 00000000000..b6cd9712570
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportingMember.cs
@@ -0,0 +1,255 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Reflection;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class ImportingMember : ImportingItem
+    {
+        private readonly ReflectionWritableMember _member;
+
+        public ImportingMember(ContractBasedImportDefinition definition, ReflectionWritableMember member, ImportType importType)
+            : base(definition, importType)
+        {
+            Assumes.NotNull(definition, member);
+
+            this._member = member;
+        }
+
+        public void SetExportedValue(object instance, object value)
+        {
+            if (RequiresCollectionNormalization())
+            {
+                this.SetCollectionMemberValue(instance, (IEnumerable)value);
+            }
+            else
+            {
+                this.SetSingleMemberValue(instance, value);
+            }
+        }
+
+        private bool RequiresCollectionNormalization()
+        {
+            if (this.Definition.Cardinality != ImportCardinality.ZeroOrMore)
+            {   // If we're not looking at a collection import, then don't 
+                // 'normalize' the collection.
+
+                return false;
+            }
+
+            if (this._member.CanWrite && this.ImportType.IsAssignableCollectionType)
+            {   // If we can simply replace the entire value of the property/field, then 
+                // we don't need to 'normalize' the collection.
+
+                return false;
+            }
+
+            return true;
+        }
+
+        private void SetSingleMemberValue(object instance, object value)
+        {
+            EnsureWritable();
+
+            try
+            {
+                this._member.SetValue(instance, value);
+            }
+            catch (TargetInvocationException exception)
+            {   // Member threw an exception. Avoid letting this 
+                // leak out as a 'raw' unhandled exception, instead,
+                // we'll add some context and rethrow.
+                throw new ComposablePartException(
+                    String.Format(CultureInfo.CurrentCulture,
+                        Strings.ReflectionModel_ImportThrewException,
+                        this._member.GetDisplayName()),
+                    Definition.ToElement(),
+                    exception.InnerException);
+            }
+            catch (TargetParameterCountException exception)
+            {
+                // Exception was a TargetParameterCountException this occurs when we try to set an Indexer that has an Import
+                // this is not supported in MEF currently.  Ideally we would validate against it, however, we already shipped
+                // so we will turn it into a ComposablePartException instead, that they should already be prepared for
+                throw new ComposablePartException(
+                    String.Format(CultureInfo.CurrentCulture,
+                        Strings.ImportNotValidOnIndexers,
+                        this._member.GetDisplayName()),
+                    Definition.ToElement(),
+                    exception.InnerException);
+            }
+        }
+
+        private void EnsureWritable()
+        {
+            if (!this._member.CanWrite)
+            {   // Property does not have a setter, or 
+                // field is marked as read-only.
+
+                throw new ComposablePartException(
+                    String.Format(CultureInfo.CurrentCulture,
+                        Strings.ReflectionModel_ImportNotWritable,
+                        this._member.GetDisplayName()),
+                        Definition.ToElement());
+            }
+        }
+
+        private void SetCollectionMemberValue(object instance, IEnumerable values)
+        {
+            Assumes.NotNull(values);
+
+            ICollection<object> collection = null;
+            Type itemType = CollectionServices.GetCollectionElementType(this.ImportType.ActualType);
+            if (itemType != null)
+            {
+                collection = GetNormalizedCollection(itemType, instance);
+            }
+
+            EnsureCollectionIsWritable(collection);
+            PopulateCollection(collection, values);
+        }
+
+        private ICollection<object> GetNormalizedCollection(Type itemType, object instance)
+        {
+            Assumes.NotNull(itemType);
+
+            object collectionObject = null;
+
+            if (this._member.CanRead)
+            {
+                try
+                {
+                    collectionObject = this._member.GetValue(instance);
+                }
+                catch (TargetInvocationException exception)
+                {
+                    throw new ComposablePartException(
+                        String.Format(CultureInfo.CurrentCulture,
+                            Strings.ReflectionModel_ImportCollectionGetThrewException,
+                            this._member.GetDisplayName()),
+                        this.Definition.ToElement(),
+                        exception.InnerException);
+                }
+            }
+
+            if (collectionObject == null)
+            {
+                ConstructorInfo constructor = this.ImportType.ActualType.GetConstructor(Type.EmptyTypes);
+
+                // If it contains a default public constructor create a new instance.
+                if (constructor != null)
+                {
+                    try
+                    {
+                        collectionObject = constructor.SafeInvoke();
+                    }
+                    catch (TargetInvocationException exception)
+                    {
+                        throw new ComposablePartException(
+                            String.Format(CultureInfo.CurrentCulture,
+                                Strings.ReflectionModel_ImportCollectionConstructionThrewException,
+                                this._member.GetDisplayName(),
+                                this.ImportType.ActualType.FullName),
+                            this.Definition.ToElement(),
+                            exception.InnerException);
+                    }
+
+                    SetSingleMemberValue(instance, collectionObject);
+                }
+            }
+
+            if (collectionObject == null)
+            {
+                throw new ComposablePartException(
+                    String.Format(CultureInfo.CurrentCulture,
+                        Strings.ReflectionModel_ImportCollectionNull,
+                        this._member.GetDisplayName()),
+                    this.Definition.ToElement());
+            }
+
+            return CollectionServices.GetCollectionWrapper(itemType, collectionObject);
+        }
+
+        [SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes")]
+        private void EnsureCollectionIsWritable(ICollection<object> collection)
+        {
+            bool isReadOnly = true;
+                
+            try
+            {
+                if (collection != null)
+                {
+                    isReadOnly = collection.IsReadOnly;
+                }
+            }
+            catch (Exception exception)
+            {
+                throw new ComposablePartException(
+                    String.Format(CultureInfo.CurrentCulture,
+                        Strings.ReflectionModel_ImportCollectionIsReadOnlyThrewException,
+                        this._member.GetDisplayName(),
+                        collection.GetType().FullName),
+                    this.Definition.ToElement(),
+                    exception);
+            }
+
+            if (isReadOnly)
+            {
+                throw new ComposablePartException(
+                    String.Format(CultureInfo.CurrentCulture,
+                        Strings.ReflectionModel_ImportCollectionNotWritable,
+                        this._member.GetDisplayName()),
+                    this.Definition.ToElement());
+            }
+        }
+
+        [SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes")]
+        private void PopulateCollection(ICollection<object> collection, IEnumerable values)
+        {
+            Assumes.NotNull(collection, values);
+
+            try
+            {
+                collection.Clear();
+            }
+            catch (Exception exception)
+            {
+                throw new ComposablePartException(
+                    String.Format(CultureInfo.CurrentCulture,
+                        Strings.ReflectionModel_ImportCollectionClearThrewException,
+                        this._member.GetDisplayName(),
+                        collection.GetType().FullName),
+                    this.Definition.ToElement(),
+                    exception);
+            }
+
+            foreach (object value in values)
+            {
+                try
+                {
+                    collection.Add(value);
+                }
+                catch (Exception exception)
+                {
+                    throw new ComposablePartException(
+                        String.Format(CultureInfo.CurrentCulture,
+                            Strings.ReflectionModel_ImportCollectionAddThrewException,
+                            this._member.GetDisplayName(),
+                            collection.GetType().FullName),
+                        this.Definition.ToElement(),
+                        exception);
+                }
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportingParameter.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportingParameter.cs
new file mode 100644
index 00000000000..0b1d15f3155
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ImportingParameter.cs
@@ -0,0 +1,16 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class ImportingParameter : ImportingItem
+    {
+        public ImportingParameter(ContractBasedImportDefinition definition, ImportType importType)
+            : base(definition, importType)
+        {
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/LazyMemberInfo.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/LazyMemberInfo.cs
new file mode 100644
index 00000000000..a3802b9637d
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/LazyMemberInfo.cs
@@ -0,0 +1,207 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Diagnostics.Contracts;
+using System.Globalization;
+using System.Linq;
+using System.Reflection;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    public struct LazyMemberInfo
+    {
+        private readonly MemberTypes _memberType;
+        private MemberInfo[] _accessors;
+        private readonly Func<MemberInfo[]> _accessorsCreator;
+
+        public LazyMemberInfo(MemberInfo member)
+        {
+            Requires.NotNull(member, "member");
+            EnsureSupportedMemberType(member.MemberType, "member");
+
+            this._accessorsCreator = null;
+            this._memberType = member.MemberType;
+            
+            switch(this._memberType)
+            {
+                case MemberTypes.Property:
+                    PropertyInfo property = (PropertyInfo)member;
+                    Assumes.NotNull(property);
+                    this._accessors = new MemberInfo[] { property.GetGetMethod(true), property.GetSetMethod(true) };
+                    break;
+                case MemberTypes.Event:
+                    EventInfo event_ = (EventInfo)member;
+                    this._accessors = new MemberInfo[] { event_.GetRaiseMethod(true), event_.GetAddMethod(true), event_.GetRemoveMethod(true) };
+                    break;
+                default:
+                    this._accessors = new MemberInfo[] { member };
+                    break;
+            }
+        }
+
+        public LazyMemberInfo(MemberTypes memberType, params MemberInfo[] accessors)
+        {
+            EnsureSupportedMemberType(memberType, "memberType");
+            Requires.NotNull(accessors, "accessors");
+            
+            string errorMessage;
+            if (!LazyMemberInfo.AreAccessorsValid(memberType, accessors, out errorMessage))
+            {
+                throw new ArgumentException(errorMessage, "accessors");
+            }
+
+            this._memberType = memberType;
+            this._accessors = accessors;
+            this._accessorsCreator = null;
+        }
+
+        public LazyMemberInfo(MemberTypes memberType, Func<MemberInfo[]> accessorsCreator)
+        {
+            EnsureSupportedMemberType(memberType, "memberType");
+            Requires.NotNull(accessorsCreator, "accessorsCreator");
+
+            this._memberType = memberType;
+            this._accessors = null;
+            this._accessorsCreator = accessorsCreator;
+        }
+
+        public MemberTypes MemberType
+        {
+            get { return this._memberType; }
+        }
+
+        public MemberInfo[] GetAccessors()
+        {
+            if ((this._accessors == null) && (this._accessorsCreator != null))
+            {
+                MemberInfo[] accessors = this._accessorsCreator.Invoke();
+
+                string errorMessage;
+                if (!LazyMemberInfo.AreAccessorsValid(this.MemberType, accessors, out errorMessage))
+                {
+                    throw new InvalidOperationException(errorMessage);
+                }
+
+                this._accessors = accessors;
+            }
+
+            return this._accessors;
+        }
+
+        public override int GetHashCode()
+        {
+            if (this._accessorsCreator != null)
+            {
+                return this.MemberType.GetHashCode() ^ this._accessorsCreator.GetHashCode();
+            }
+            else
+            {
+                Assumes.NotNull(this._accessors);
+                Assumes.NotNull(this._accessors[0]);
+                return this.MemberType.GetHashCode() ^ this._accessors[0].GetHashCode();
+            }
+        }
+
+        public override bool Equals(object obj)
+        {
+            LazyMemberInfo that = (LazyMemberInfo)obj;
+
+            // Difefrent member types mean different members
+            if (this._memberType != that._memberType)
+            {
+                return false;
+            }
+
+            // if any of the lazy memebers create accessors in a delay-loaded fashion, we simply compare the creators
+            if ((this._accessorsCreator != null) || (that._accessorsCreator != null))
+            {
+                return object.Equals(this._accessorsCreator, that._accessorsCreator);
+            }
+
+            // we are dealing with explicitly passed accessors in both cases
+            Assumes.NotNull(this._accessors);
+            Assumes.NotNull(that._accessors);
+            return this._accessors.SequenceEqual(that._accessors);
+        }
+
+        public static bool operator ==(LazyMemberInfo left, LazyMemberInfo right)
+        {
+            return left.Equals(right);
+        }
+
+        public static bool operator !=(LazyMemberInfo left, LazyMemberInfo right)
+        {
+            return !left.Equals(right);
+        }
+
+        [ContractArgumentValidator]
+        private static void EnsureSupportedMemberType(MemberTypes memberType, string argument)
+        {
+            MemberTypes supportedTypes = MemberTypes.TypeInfo | MemberTypes.NestedType | MemberTypes.Constructor | MemberTypes.Field | MemberTypes.Method | MemberTypes.Property | MemberTypes.Event;
+            Requires.IsInMembertypeSet(memberType, argument, supportedTypes);
+        }
+
+        private static bool AreAccessorsValid(MemberTypes memberType, MemberInfo[] accessors, out string errorMessage)
+        {
+            errorMessage = string.Empty;
+            if (accessors == null)
+            {
+                errorMessage = Strings.LazyMemberInfo_AccessorsNull;
+                return false;
+            }
+
+            if (accessors.All(accessor => accessor == null))
+            {
+                errorMessage = Strings.LazyMemberInfo_NoAccessors;
+                return false;
+            }
+
+            switch (memberType)
+            {
+                case MemberTypes.Property:
+                    if (accessors.Length != 2)
+                    {
+                        errorMessage = Strings.LazyMemberInfo_InvalidPropertyAccessors_Cardinality;
+                        return false;
+                    }
+
+                    if (accessors.Where(accessor => (accessor != null) && (accessor.MemberType != MemberTypes.Method)).Any())
+                    {
+                        errorMessage = Strings.LazyMemberinfo_InvalidPropertyAccessors_AccessorType;
+                        return false;
+                    }
+
+                    break;
+
+                case MemberTypes.Event:
+                    if (accessors.Length != 3)
+                    {
+                        errorMessage = Strings.LazyMemberInfo_InvalidEventAccessors_Cardinality;
+                        return false;
+                    }
+
+                    if (accessors.Where(accessor => (accessor != null) && (accessor.MemberType != MemberTypes.Method)).Any())
+                    {
+                        errorMessage = Strings.LazyMemberinfo_InvalidEventAccessors_AccessorType;
+                        return false;
+                    }
+
+                    break;
+
+                default:
+                    if (
+                        (accessors.Length != 1) ||
+                        ((accessors.Length == 1) && (accessors[0].MemberType != memberType)))
+                    {
+                        errorMessage = string.Format(CultureInfo.CurrentCulture, Strings.LazyMemberInfo_InvalidAccessorOnSimpleMember, memberType);
+                        return false;
+                    }
+                   
+                    break;
+            }
+            return true;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/PartCreatorExportDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/PartCreatorExportDefinition.cs
new file mode 100644
index 00000000000..517dd59da1a
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/PartCreatorExportDefinition.cs
@@ -0,0 +1,62 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class PartCreatorExportDefinition : ExportDefinition
+    {
+        private readonly ExportDefinition _productDefinition;
+        private IDictionary<string, object> _metadata;
+
+        public PartCreatorExportDefinition(ExportDefinition productDefinition)
+            : base()
+        {
+            this._productDefinition = productDefinition;
+        }
+
+        public override string ContractName
+        {
+            get
+            {
+                return CompositionConstants.PartCreatorContractName;
+            }
+        }
+
+        public override IDictionary<string, object> Metadata
+        {
+            get
+            {
+                if (this._metadata == null)
+                {
+                    var metadata = new Dictionary<string, object>(this._productDefinition.Metadata);
+                    metadata[CompositionConstants.ExportTypeIdentityMetadataName] = CompositionConstants.PartCreatorTypeIdentity;
+                    metadata[CompositionConstants.ProductDefinitionMetadataName] = this._productDefinition;
+
+                    this._metadata = metadata.AsReadOnly();
+                }
+                return this._metadata;
+            }
+        }
+
+        internal static bool IsProductConstraintSatisfiedBy(ImportDefinition productImportDefinition, ExportDefinition exportDefinition)
+        {
+            object productValue = null;
+            if (exportDefinition.Metadata.TryGetValue(CompositionConstants.ProductDefinitionMetadataName, out productValue))
+            {
+                ExportDefinition productDefinition = productValue as ExportDefinition;
+
+                if (productDefinition != null)
+                {
+                    return productImportDefinition.IsConstraintSatisfiedBy(productDefinition);
+                }
+            }
+
+            return false;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/PartCreatorMemberImportDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/PartCreatorMemberImportDefinition.cs
new file mode 100644
index 00000000000..e98d7446bcd
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/PartCreatorMemberImportDefinition.cs
@@ -0,0 +1,49 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq.Expressions;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class PartCreatorMemberImportDefinition : ReflectionMemberImportDefinition, IPartCreatorImportDefinition
+    {
+        private readonly ContractBasedImportDefinition _productImportDefinition;
+
+        public PartCreatorMemberImportDefinition(
+            LazyMemberInfo importingLazyMember,
+            ICompositionElement origin,
+            ContractBasedImportDefinition productImportDefinition)
+            : base(importingLazyMember, CompositionConstants.PartCreatorContractName, CompositionConstants.PartCreatorTypeIdentity,
+                productImportDefinition.RequiredMetadata, productImportDefinition.Cardinality, productImportDefinition.IsRecomposable, false, productImportDefinition.RequiredCreationPolicy, MetadataServices.EmptyMetadata, origin)
+        {
+            Assumes.NotNull(productImportDefinition);
+            this._productImportDefinition = productImportDefinition;
+        }
+
+        public ContractBasedImportDefinition ProductImportDefinition { get { return this._productImportDefinition; } }
+
+        [SuppressMessage("Microsoft.Contracts", "CC1055", Justification = "Precondition is being validated in the call to base")]  
+        public override bool IsConstraintSatisfiedBy(ExportDefinition exportDefinition)
+        {
+            if (!base.IsConstraintSatisfiedBy(exportDefinition))
+            {
+                return false;
+            }
+
+            return PartCreatorExportDefinition.IsProductConstraintSatisfiedBy(this._productImportDefinition, exportDefinition);
+        }
+
+        public override Expression<Func<ExportDefinition, bool>> Constraint
+        {
+            get
+            {
+                return ConstraintServices.CreatePartCreatorConstraint(base.Constraint, this._productImportDefinition);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/PartCreatorParameterImportDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/PartCreatorParameterImportDefinition.cs
new file mode 100644
index 00000000000..79aeb0c186a
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/PartCreatorParameterImportDefinition.cs
@@ -0,0 +1,49 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq.Expressions;
+using System.Reflection;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class PartCreatorParameterImportDefinition : ReflectionParameterImportDefinition, IPartCreatorImportDefinition
+    {
+        private readonly ContractBasedImportDefinition _productImportDefinition;
+
+        public PartCreatorParameterImportDefinition(
+            Lazy<ParameterInfo> importingLazyParameter,
+            ICompositionElement origin,
+            ContractBasedImportDefinition productImportDefinition)
+            : base(importingLazyParameter, CompositionConstants.PartCreatorContractName, CompositionConstants.PartCreatorTypeIdentity,
+                productImportDefinition.RequiredMetadata, productImportDefinition.Cardinality, CreationPolicy.Any, MetadataServices.EmptyMetadata, origin)
+        {
+            Assumes.NotNull(productImportDefinition);
+            this._productImportDefinition = productImportDefinition;
+        }
+
+        public ContractBasedImportDefinition ProductImportDefinition { get { return this._productImportDefinition; } }
+
+        [SuppressMessage("Microsoft.Contracts", "CC1055", Justification = "Precondition is being validated in the call to base")]  
+        public override bool IsConstraintSatisfiedBy(ExportDefinition exportDefinition)
+        {
+            if (!base.IsConstraintSatisfiedBy(exportDefinition))
+            {
+                return false;
+            }
+            return PartCreatorExportDefinition.IsProductConstraintSatisfiedBy(this._productImportDefinition, exportDefinition);
+        }
+
+        public override Expression<Func<ExportDefinition, bool>> Constraint
+        {
+            get
+            {
+                return ConstraintServices.CreatePartCreatorConstraint(base.Constraint, this._productImportDefinition);
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionComposablePart.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionComposablePart.cs
new file mode 100644
index 00000000000..72e8207b1db
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionComposablePart.cs
@@ -0,0 +1,582 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Contracts;
+using System.Globalization;
+using System.Linq;
+using System.Reflection;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    // This 
+    internal class ReflectionComposablePart : ComposablePart, ICompositionElement
+    {
+        private readonly ReflectionComposablePartDefinition _definition;
+        private readonly Dictionary<ImportDefinition, object> _importValues = new Dictionary<ImportDefinition, object>();
+        private readonly Dictionary<ImportDefinition, ImportingItem> _importsCache = new Dictionary<ImportDefinition, ImportingItem>();
+        private readonly Dictionary<int, ExportingMember> _exportsCache = new Dictionary<int, ExportingMember>();
+        private bool _invokeImportsSatisfied = true;
+        private bool _invokingImportsSatisfied = false;
+        private bool _initialCompositionComplete = false;
+        private volatile object _cachedInstance;
+        private object _lock = new object();
+
+        public ReflectionComposablePart(ReflectionComposablePartDefinition definition)
+        {
+            Requires.NotNull(definition, "definition");
+
+            this._definition = definition;
+        }
+
+        public ReflectionComposablePart(ReflectionComposablePartDefinition definition, object attributedPart)
+        {
+            Requires.NotNull(definition, "definition");
+            Requires.NotNull(attributedPart, "attributedPart");
+
+            this._definition = definition;
+
+            if (attributedPart is ValueType)
+            {
+                throw new ArgumentException(Strings.ArgumentValueType, "attributedPart");
+            }
+            this._cachedInstance = attributedPart;
+        }
+
+        protected virtual void EnsureRunning()
+        {
+        }
+
+        [ContractArgumentValidator]
+        [SuppressMessage("Microsoft.Contracts", "CC1053")]
+        protected void RequiresRunning()
+        {
+            this.EnsureRunning();
+        }
+
+        protected virtual void ReleaseInstanceIfNecessary(object instance)
+        {
+        }
+
+        protected object CachedInstance
+        {
+            get
+            {
+                lock (this._lock)
+                {
+                    return this._cachedInstance;
+                }
+            }
+        }
+
+        public ReflectionComposablePartDefinition Definition
+        {
+            get 
+            {
+                this.RequiresRunning();
+                return this._definition; 
+            }
+        }
+
+        public override IDictionary<string, object> Metadata
+        {
+            get
+            {
+                this.RequiresRunning();
+                return this.Definition.Metadata;
+            }
+        }
+
+        public sealed override IEnumerable<ImportDefinition> ImportDefinitions
+        {
+            get
+            {
+                this.RequiresRunning();
+                return this.Definition.ImportDefinitions;
+            }
+        }
+
+        public sealed override IEnumerable<ExportDefinition> ExportDefinitions
+        {
+            get
+            {
+                this.RequiresRunning();
+                return this.Definition.ExportDefinitions;
+            }
+        }
+
+        string ICompositionElement.DisplayName
+        {
+            get { return GetDisplayName(); }
+        }
+
+        ICompositionElement ICompositionElement.Origin
+        {
+            get { return Definition; }
+        }
+
+        // This is the ONLY method which is not executed under the ImportEngine composition lock.
+        // We need to protect all state that is accesses
+        public override object GetExportedValue(ExportDefinition definition)
+        {
+            this.RequiresRunning();
+            // given the implementation of the ImportEngine, this iwll be called under a lock if the part is still being composed
+            // This is only called outside of the lock when the part is fully composed
+            // based on that we only protect:
+            // _exportsCache - and thus all calls to GetExportingMemberFromDefinition
+            // access to _importValues
+            // access to _initialCompositionComplete
+            // access to _instance
+            Requires.NotNull(definition, "definition");
+
+            ExportingMember member = null;
+            lock (this._lock)
+            {
+                member = GetExportingMemberFromDefinition(definition);
+                if (member == null)
+                {
+                    throw ExceptionBuilder.CreateExportDefinitionNotOnThisComposablePart("definition");
+                }
+                this.EnsureGettable();
+            }
+
+            return this.GetExportedValue(member);
+        }
+
+        public override void SetImport(ImportDefinition definition, IEnumerable<Export> exports)
+        {
+            this.RequiresRunning();
+            Requires.NotNull(definition, "definition");
+            Requires.NotNull(exports, "exports");;
+
+            ImportingItem item = GetImportingItemFromDefinition(definition);
+            if (item == null)
+            {
+                throw ExceptionBuilder.CreateImportDefinitionNotOnThisComposablePart("definition");
+            }
+
+            EnsureSettable(definition);
+
+            // Avoid walking over exports many times
+            Export[] exportsAsArray = exports.AsArray();
+            EnsureCardinality(definition, exportsAsArray);
+
+            SetImport(item, exportsAsArray);
+        }
+
+        public override void Activate()
+        {
+            this.RequiresRunning();
+
+            this.SetNonPrerequisiteImports();
+
+            // Whenever we are composed/recomposed notify the instance
+            this.NotifyImportSatisfied();
+
+            lock (this._lock)
+            {
+                this._initialCompositionComplete = true;
+            }
+        }
+
+        public override string ToString()
+        {
+            return this.GetDisplayName();
+        }
+
+        private object GetExportedValue(ExportingMember member)
+        {
+            object instance = null;
+            if (member.RequiresInstance)
+            {   // Only activate the instance if we actually need to
+
+                instance = this.GetInstanceActivatingIfNeeded();
+            }
+
+            return member.GetExportedValue(instance, this._lock);
+        }
+
+        private void SetImport(ImportingItem item, Export[] exports)
+        {
+            object value = item.CastExportsToImportType(exports);
+
+            lock (this._lock)
+            {
+                this._invokeImportsSatisfied = true;
+                this._importValues[item.Definition] = value;
+            }
+        }
+
+        private object GetInstanceActivatingIfNeeded()
+        {
+            if (this._cachedInstance != null)
+            {
+                return this._cachedInstance;
+            }
+            else
+            {
+                ConstructorInfo constructor = null;
+                object[] arguments = null;
+                // determine whether activation is required, and collect necessary information for activation
+                // we need to do that under a lock
+                lock (this._lock)
+                {
+                    if (!this.RequiresActivation())
+                    {
+                        return null;
+                    }
+
+                    constructor = this.Definition.GetConstructor();
+                    if (constructor == null)
+                    {
+                        throw new ComposablePartException(
+                            String.Format(CultureInfo.CurrentCulture,
+                                Strings.ReflectionModel_PartConstructorMissing,
+                                this.Definition.GetPartType().FullName),
+                            this.Definition.ToElement());
+                    }
+                    arguments = this.GetConstructorArguments();
+                }
+
+                // create instance outside of the lock
+                object createdInstance = this.CreateInstance(constructor, arguments);
+
+                SetPrerequisiteImports();
+
+                // set the created instance
+                lock (this._lock)
+                {
+                    if (this._cachedInstance == null)
+                    {
+                        this._cachedInstance = createdInstance;
+                        createdInstance = null;
+                    }
+                }
+
+                // if the instance has been already set
+                if (createdInstance == null)
+                {
+                    this.ReleaseInstanceIfNecessary(createdInstance);
+                }
+            }
+
+            return this._cachedInstance;
+        }
+
+        private object[] GetConstructorArguments()
+        {
+            ReflectionParameterImportDefinition[] parameterImports = this.ImportDefinitions.OfType<ReflectionParameterImportDefinition>().ToArray();
+            object[] arguments = new object[parameterImports.Length];
+
+            this.UseImportedValues(
+                parameterImports,
+                (import, definition, value) =>
+                {
+                    if (definition.Cardinality == ImportCardinality.ZeroOrMore && !import.ImportType.IsAssignableCollectionType)
+                    {
+                        throw new ComposablePartException(
+                            String.Format(CultureInfo.CurrentCulture,
+                                Strings.ReflectionModel_ImportManyOnParameterCanOnlyBeAssigned,
+                                this.Definition.GetPartType().FullName,
+                                definition.ImportingLazyParameter.Value.Name),
+                            this.Definition.ToElement());
+                    }
+
+                    arguments[definition.ImportingLazyParameter.Value.Position] = value;
+                },
+                true);
+
+            return arguments;
+        }
+
+        // alwayc called under a lock
+        private bool RequiresActivation()
+        {
+            // If we have any imports then we need activation
+            // (static imports are not supported)
+            if (this.ImportDefinitions.Any())
+            {
+                return true;
+            }
+
+            // If we have any instance exports, then we also 
+            // need activation.
+            return this.ExportDefinitions.Any(definition =>
+            {
+                ExportingMember member = GetExportingMemberFromDefinition(definition);
+
+                return member.RequiresInstance;
+            });
+        }
+
+        // this is called under a lock
+        private void EnsureGettable()
+        {
+            // If we're already composed then we know that 
+            // all pre-req imports have been satisfied
+            if (_initialCompositionComplete)
+            {
+                return;
+            }
+
+            // Make sure all pre-req imports have been set
+            foreach (ImportDefinition definition in ImportDefinitions.Where(definition => definition.IsPrerequisite))
+            {
+                if (!this._importValues.ContainsKey(definition))
+                {
+                    throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture,
+                                                            Strings.InvalidOperation_GetExportedValueBeforePrereqImportSet,
+                                                            definition.ToElement().DisplayName));
+                }
+            }
+        }
+
+        private void EnsureSettable(ImportDefinition definition)
+        {
+            lock (this._lock)
+            {
+                if (this._initialCompositionComplete && !definition.IsRecomposable)
+                {
+                    throw new InvalidOperationException(Strings.InvalidOperation_DefinitionCannotBeRecomposed);
+                }
+            }
+        }
+
+        private static void EnsureCardinality(ImportDefinition definition, Export[] exports)
+        {
+            Requires.NullOrNotNullElements(exports, "exports");
+
+            ExportCardinalityCheckResult result = ExportServices.CheckCardinality(definition, exports);
+
+            switch (result)
+            {
+                case ExportCardinalityCheckResult.NoExports:
+                    throw new ArgumentException(Strings.Argument_ExportsEmpty, "exports");
+
+                case ExportCardinalityCheckResult.TooManyExports:
+                    throw new ArgumentException(Strings.Argument_ExportsTooMany, "exports");
+
+                default:
+                    Assumes.IsTrue(result == ExportCardinalityCheckResult.Match);
+                    break;
+            }
+        }
+
+        private object CreateInstance(ConstructorInfo constructor, object[] arguments)
+        { 
+            Exception exception = null;
+            object instance = null;
+
+            try
+            {
+                instance = constructor.SafeInvoke(arguments);
+            }
+            catch (TypeInitializationException ex) 
+            { 
+                exception = ex; 
+            }
+            catch (TargetInvocationException ex)
+            {
+                exception = ex.InnerException;
+            }
+            
+            if (exception != null)
+            {
+                throw new ComposablePartException(
+                    String.Format(CultureInfo.CurrentCulture,
+                        Strings.ReflectionModel_PartConstructorThrewException,
+                        Definition.GetPartType().FullName),
+                    Definition.ToElement(),
+                    exception);
+            }
+
+            return instance;
+        }
+
+        private void SetNonPrerequisiteImports()
+        {
+            IEnumerable<ImportDefinition> members = this.ImportDefinitions.Where(import => !import.IsPrerequisite);
+
+            // NOTE: Dev10 484204 The validation is turned off for post imports because of it broke declarative composition
+            this.UseImportedValues(members, SetExportedValueForImport, false);
+        }
+
+        private void SetPrerequisiteImports()
+        {
+            IEnumerable<ImportDefinition> members = this.ImportDefinitions.Where(import => import.IsPrerequisite);
+
+            // NOTE: Dev10 484204 The validation is turned off for post imports because of it broke declarative composition
+            this.UseImportedValues(members, SetExportedValueForImport, false);
+        }
+
+        private void SetExportedValueForImport(ImportingItem import, ImportDefinition definition, object value)
+        {
+            ImportingMember importMember = (ImportingMember)import;
+
+            object instance = this.GetInstanceActivatingIfNeeded();
+
+            importMember.SetExportedValue(instance, value);
+        }
+
+        private void UseImportedValues<TImportDefinition>(IEnumerable<TImportDefinition> definitions, Action<ImportingItem, TImportDefinition, object> useImportValue, bool errorIfMissing)
+            where TImportDefinition : ImportDefinition
+        {
+            var result = CompositionResult.SucceededResult;
+
+            foreach (var definition in definitions)
+            {
+                ImportingItem import = GetImportingItemFromDefinition(definition);
+
+                object value;
+                if (!TryGetImportValue(definition, out value))
+                {
+                    if (!errorIfMissing)
+                    {
+                        continue;
+                    }
+
+                    if (definition.Cardinality == ImportCardinality.ExactlyOne)
+                    {
+                        var error = CompositionError.Create(
+                            CompositionErrorId.ImportNotSetOnPart,
+                            Strings.ImportNotSetOnPart,
+                            this.Definition.GetPartType().FullName,
+                            definition.ToString());
+                        result = result.MergeError(error);
+                        continue;
+                    }
+                    else
+                    {
+                        value = import.CastExportsToImportType(new Export[0]);
+                    }
+                }
+
+                useImportValue(import, definition, value);
+            }
+
+            result.ThrowOnErrors();
+        }
+
+        private bool TryGetImportValue(ImportDefinition definition, out object value)
+        {
+            lock (this._lock)
+            {
+                if (this._importValues.TryGetValue(definition, out value))
+                {
+                    this._importValues.Remove(definition);
+                    return true;
+                }
+            }
+
+            value = null;
+            return false;
+        }
+
+        [SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes")]
+        private void NotifyImportSatisfied()
+        {
+            if (this._invokeImportsSatisfied && !this._invokingImportsSatisfied)
+            {
+                IPartImportsSatisfiedNotification notify = this.GetInstanceActivatingIfNeeded() as IPartImportsSatisfiedNotification;
+                if (notify != null)
+                {
+                    try
+                    {
+                        // Reentrancy on composition notifications is allowed, so set this first to avoid 
+                        // an infinte loop of notifications.
+                        this._invokingImportsSatisfied = true;
+
+                        notify.OnImportsSatisfied();
+                    }
+                    catch (Exception exception)
+                    {
+                        throw new ComposablePartException(
+                            String.Format(CultureInfo.CurrentCulture,
+                                Strings.ReflectionModel_PartOnImportsSatisfiedThrewException,
+                                Definition.GetPartType().FullName),
+                            Definition.ToElement(),
+                            exception);
+                    }
+                    finally
+                    {
+                        this._invokingImportsSatisfied = false;
+                    }
+
+                    this._invokeImportsSatisfied = false;
+                }
+            }
+        }
+
+        // this is always called under a lock
+        private ExportingMember GetExportingMemberFromDefinition(ExportDefinition definition)
+        {
+            ExportingMember result;
+            ReflectionMemberExportDefinition reflectionExport = definition as ReflectionMemberExportDefinition;
+            if (reflectionExport == null)
+            {
+                return null;
+            }
+
+            int exportIndex = reflectionExport.GetIndex();
+            if (!_exportsCache.TryGetValue(exportIndex, out result))
+            {
+                result = GetExportingMember(definition);
+                if (result != null)
+                {
+                    _exportsCache[exportIndex] = result;
+                }
+            }
+
+            return result;
+        }
+
+        private ImportingItem GetImportingItemFromDefinition(ImportDefinition definition)
+        {
+            ImportingItem result;
+            if (!_importsCache.TryGetValue(definition, out result))
+            {
+                result = GetImportingItem(definition);
+                if (result != null)
+                {
+                    _importsCache[definition] = result;
+                }
+            }
+
+            return result;
+        }
+
+        private static ImportingItem GetImportingItem(ImportDefinition definition)
+        {
+            ReflectionImportDefinition reflectionDefinition = definition as ReflectionImportDefinition;
+            if (reflectionDefinition != null)
+            {
+                return reflectionDefinition.ToImportingItem();
+            }
+
+            // Don't recognize it
+            return null;
+        }
+
+        private static ExportingMember GetExportingMember(ExportDefinition definition)
+        {
+            ReflectionMemberExportDefinition exportDefinition = definition as ReflectionMemberExportDefinition;
+            if (exportDefinition != null)
+            {
+                return exportDefinition.ToExportingMember();
+            }
+
+            // Don't recognize it
+            return null;
+        }
+
+        private string GetDisplayName()
+        {
+            return this._definition.GetPartType().GetDisplayName();
+        }
+    }
+}
\ No newline at end of file
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionComposablePartDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionComposablePartDefinition.cs
new file mode 100644
index 00000000000..010a7329ec8
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionComposablePartDefinition.cs
@@ -0,0 +1,262 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using System.Reflection;
+using System.Threading;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using System.ComponentModel.Composition.Hosting;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class ReflectionComposablePartDefinition : ComposablePartDefinition, ICompositionElement
+    {
+        private readonly IReflectionPartCreationInfo _creationInfo;
+
+        private volatile IEnumerable<ImportDefinition> _imports;
+        private volatile IEnumerable<ExportDefinition> _exports;
+        private volatile IDictionary<string, object> _metadata;
+        private volatile ConstructorInfo _constructor;
+        private object _lock = new object();
+
+        public ReflectionComposablePartDefinition(IReflectionPartCreationInfo creationInfo)
+        {
+            Assumes.NotNull(creationInfo);
+            this._creationInfo = creationInfo;
+        }
+
+        public Type GetPartType()
+        {
+            return this._creationInfo.GetPartType();
+        }
+
+        public Lazy<Type> GetLazyPartType()
+        {
+            return this._creationInfo.GetLazyPartType();
+        }
+
+        public ConstructorInfo GetConstructor()
+        {
+            if (this._constructor == null)
+            {
+                ConstructorInfo constructor = this._creationInfo.GetConstructor();
+                lock (this._lock)
+                {
+                    if (this._constructor == null)
+                    {
+                        this._constructor = constructor;
+                    }
+                }
+            }
+
+            return this._constructor;
+        }
+
+        public override IEnumerable<ExportDefinition> ExportDefinitions
+        {
+            get
+            {
+                if (this._exports == null)
+                {
+                    ExportDefinition[] exports = this._creationInfo.GetExports().ToArray();
+                    lock (this._lock)
+                    {
+                        if (this._exports == null)
+                        {
+                            this._exports = exports;
+                        }
+                    }
+                }
+                return this._exports;
+            }
+        }
+
+        public override IEnumerable<ImportDefinition> ImportDefinitions
+        {
+            get
+            {
+                if (this._imports == null)
+                {
+                    ImportDefinition[] imports = this._creationInfo.GetImports().ToArray();
+                    lock (this._lock)
+                    {
+                        if (this._imports == null)
+                        {
+                            this._imports = imports;
+                        }
+                    }
+                }
+                return this._imports;
+            }
+        }
+
+        public override IDictionary<string, object> Metadata
+        {
+            get
+            {
+                if (this._metadata == null)
+                {
+                    IDictionary<string, object> metadata = this._creationInfo.GetMetadata().AsReadOnly();
+                    lock (this._lock)
+                    {
+                        if (this._metadata == null)
+                        {
+                            this._metadata = metadata;
+                        }
+                    }
+                }
+                return this._metadata;
+            }
+        }
+
+        internal bool IsDisposalRequired
+        {
+            get
+            {
+                return this._creationInfo.IsDisposalRequired;
+            }
+        }
+
+        [SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope")]
+        public override ComposablePart CreatePart()
+        {
+            if (this.IsDisposalRequired)
+            {
+                return new DisposableReflectionComposablePart(this);
+            }
+            else
+            {
+                return new ReflectionComposablePart(this);
+            }
+        }
+
+        internal override ComposablePartDefinition GetGenericPartDefinition()
+        {
+            GenericSpecializationPartCreationInfo genericCreationInfo = this._creationInfo as GenericSpecializationPartCreationInfo;
+            if (genericCreationInfo != null)
+            {
+                return genericCreationInfo.OriginalPart;
+            }
+
+            return null;
+        }
+
+        internal override IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>> GetExports(ImportDefinition definition)
+        {
+            if (this.IsGeneric())
+            {
+                List<Tuple<ComposablePartDefinition, ExportDefinition>> exports = null;
+
+                var genericParameters = (definition.Metadata.Count > 0) ? definition.Metadata.GetValue<IEnumerable<object>>(CompositionConstants.GenericParametersMetadataName) : null;
+                // if and only if generic parameters have been supplied can we attempt to "close" the generic
+                if (genericParameters != null)
+                {
+                    Type[] genericTypeParameters = null;
+                    // we only undestand types
+                    if (TryGetGenericTypeParameters(genericParameters, out genericTypeParameters))
+                    {
+                        // go through all orders of generic parameters that part exports allows
+                        foreach (Type[] candidateParameters in this.GetCandidateParameters(genericTypeParameters))
+                        {
+                            ComposablePartDefinition candidatePart = null;
+                            if (this.TryMakeGenericPartDefinition(candidateParameters, out candidatePart))
+                            {
+                                var candidatePartExports = candidatePart.GetExports(definition);
+                                if (candidatePartExports != ComposablePartDefinition._EmptyExports)
+                                {
+                                    exports = exports.FastAppendToListAllowNulls(candidatePartExports);
+                                }
+                            }
+                        }
+                    }
+                }
+                return exports ?? _EmptyExports;
+            }
+            else
+            {
+                return base.GetExports(definition);
+            }
+        }
+
+        private IEnumerable<Type[]> GetCandidateParameters(Type[] genericParameters)
+        {
+            // we iterate over all exports and find only generic ones. Assuming the arity matches, we reorder the original parameters
+            foreach (ExportDefinition export in this.ExportDefinitions)
+            {
+                var genericParametersOrder = export.Metadata.GetValue<int[]>(CompositionConstants.GenericExportParametersOrderMetadataName);
+                if ((genericParametersOrder != null) && (genericParametersOrder.Length == genericParameters.Length))
+                {
+                    yield return GenericServices.Reorder(genericParameters, genericParametersOrder);
+                }
+            }
+        }
+
+        private static bool TryGetGenericTypeParameters(IEnumerable<object> genericParameters, out Type[] genericTypeParameters)
+        {
+            genericTypeParameters = genericParameters as Type[];
+            if (genericTypeParameters == null)
+            {
+                object[] genericParametersAsArray = genericParameters.AsArray();
+                genericTypeParameters = new Type[genericParametersAsArray.Length];
+                for (int i = 0; i < genericParametersAsArray.Length; i++)
+                {
+                    genericTypeParameters[i] = genericParametersAsArray[i] as Type;
+                    if (genericTypeParameters[i] == null)
+                    {
+                        return false;
+                    }
+                }
+            }
+            return true;
+        }
+
+        internal bool TryMakeGenericPartDefinition(Type[] genericTypeParameters, out ComposablePartDefinition genericPartDefinition)
+        {
+            genericPartDefinition = null;
+
+            if (!GenericSpecializationPartCreationInfo.CanSpecialize(this.Metadata, genericTypeParameters))
+            {
+                return false;
+            }
+
+            genericPartDefinition = new ReflectionComposablePartDefinition(new GenericSpecializationPartCreationInfo(this._creationInfo, this, genericTypeParameters));
+            return true;
+        }
+
+        string ICompositionElement.DisplayName
+        {
+            get { return this._creationInfo.DisplayName; }
+        }
+
+        ICompositionElement ICompositionElement.Origin
+        {
+            get { return this._creationInfo.Origin; }
+        }
+
+        public override string ToString()
+        {
+            return this._creationInfo.DisplayName;
+        }
+
+        public override bool Equals(object obj)
+        {
+            ReflectionComposablePartDefinition that = obj as ReflectionComposablePartDefinition;
+            if (that == null)
+            {
+                return false;
+            }
+
+            return this._creationInfo.Equals(that._creationInfo);
+        }
+
+        public override int GetHashCode()
+        {
+            return this._creationInfo.GetHashCode();
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionExtensions.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionExtensions.cs
new file mode 100644
index 00000000000..a5ac1bccf4a
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionExtensions.cs
@@ -0,0 +1,116 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Reflection;
+using Microsoft.Internal;
+using System.Threading;
+using System.Collections.Generic;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal static class ReflectionExtensions
+    {
+        public static ReflectionMember ToReflectionMember(this LazyMemberInfo lazyMember)
+        {
+            MemberInfo[] accessors = lazyMember.GetAccessors();
+            MemberTypes memberType = lazyMember.MemberType;
+
+            switch (memberType)
+            {
+                case MemberTypes.Field:
+                    Assumes.IsTrue(accessors.Length == 1);
+                    return ((FieldInfo)accessors[0]).ToReflectionField();
+
+                case MemberTypes.Property:
+                    Assumes.IsTrue(accessors.Length == 2);
+                    return ReflectionExtensions.CreateReflectionProperty((MethodInfo)accessors[0], (MethodInfo)accessors[1]);
+
+                case MemberTypes.NestedType:
+                case MemberTypes.TypeInfo:
+                    return ((Type)accessors[0]).ToReflectionType();
+
+                default:
+                    Assumes.IsTrue(memberType == MemberTypes.Method);
+                    return ((MethodInfo)accessors[0]).ToReflectionMethod();
+            }
+        }
+
+        public static LazyMemberInfo ToLazyMember(this MemberInfo member)
+        {
+            Assumes.NotNull(member);
+
+            if (member.MemberType == MemberTypes.Property)
+            {
+                PropertyInfo property = member as PropertyInfo;
+                Assumes.NotNull(property);
+
+                MemberInfo[] accessors = new MemberInfo[] { property.GetGetMethod(true), property.GetSetMethod(true)};
+                return new LazyMemberInfo(MemberTypes.Property, accessors);
+            }
+            else
+            {
+                return new LazyMemberInfo(member);
+            }
+        }
+
+        public static ReflectionWritableMember ToReflectionWriteableMember(this LazyMemberInfo lazyMember)
+        {
+            Assumes.IsTrue((lazyMember.MemberType == MemberTypes.Field) || (lazyMember.MemberType == MemberTypes.Property));
+
+            ReflectionWritableMember reflectionMember = lazyMember.ToReflectionMember() as ReflectionWritableMember;
+            Assumes.NotNull(reflectionMember);
+
+            return reflectionMember;
+        }
+
+
+        public static ReflectionProperty ToReflectionProperty(this PropertyInfo property)
+        {
+            Assumes.NotNull(property);
+            return CreateReflectionProperty(property.GetGetMethod(true), property.GetSetMethod(true));
+        }
+
+        public static ReflectionProperty CreateReflectionProperty(MethodInfo getMethod, MethodInfo setMethod)
+        {
+            Assumes.IsTrue(getMethod != null || setMethod != null);
+
+            return new ReflectionProperty(getMethod, setMethod);
+        }
+
+        public static ReflectionParameter ToReflectionParameter(this ParameterInfo parameter)
+        {
+            Assumes.NotNull(parameter);
+            return new ReflectionParameter(parameter);
+        }
+
+        public static ReflectionMethod ToReflectionMethod(this MethodInfo method)
+        {
+            Assumes.NotNull(method);
+            return new ReflectionMethod(method);
+        }
+
+        public static ReflectionField ToReflectionField(this FieldInfo field)
+        {
+            Assumes.NotNull(field);
+            return new ReflectionField(field);
+        }
+
+        public static ReflectionType ToReflectionType(this Type type)
+        {
+            Assumes.NotNull(type);
+            return new ReflectionType(type);
+        }
+
+        public static ReflectionWritableMember ToReflectionWritableMember(this MemberInfo member)
+        {
+            Assumes.NotNull(member);
+            if (member.MemberType == MemberTypes.Property)
+            {
+                return ((PropertyInfo)member).ToReflectionProperty();
+            }
+
+            return ((FieldInfo)member).ToReflectionField();
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionField.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionField.cs
new file mode 100644
index 00000000000..1cac368742c
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionField.cs
@@ -0,0 +1,67 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Reflection;
+using Microsoft.Internal;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class ReflectionField : ReflectionWritableMember
+    {
+        private readonly FieldInfo _field;
+
+        public ReflectionField(FieldInfo field)
+        {
+            Assumes.NotNull(field);
+
+            this._field = field;
+        }
+
+        public FieldInfo UndelyingField
+        {
+            get { return this._field; }
+        }
+
+        public override MemberInfo UnderlyingMember
+        {
+            get { return this.UndelyingField; }
+        }
+
+        public override bool CanRead
+        {
+            get { return true; }
+        }
+
+        public override bool CanWrite
+        {
+            get { return !this.UndelyingField.IsInitOnly; }
+        }
+
+        public override bool RequiresInstance
+        {
+            get { return !this.UndelyingField.IsStatic; }
+        }
+
+        public override Type ReturnType
+        {
+            get { return this.UndelyingField.FieldType; }
+        }
+
+        public override ReflectionItemType ItemType
+        {
+            get { return ReflectionItemType.Field; }
+        }
+
+        public override object GetValue(object instance)
+        {
+            return this.UndelyingField.SafeGetValue(instance);
+        }
+
+        public override void SetValue(object instance, object value)
+        {
+            this.UndelyingField.SafeSetValue(instance, value);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionImportDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionImportDefinition.cs
new file mode 100644
index 00000000000..cda7f726801
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionImportDefinition.cs
@@ -0,0 +1,48 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Globalization;
+using System.Reflection;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal abstract class ReflectionImportDefinition : ContractBasedImportDefinition, ICompositionElement
+    {
+        private readonly ICompositionElement _origin;
+
+        public ReflectionImportDefinition(
+            string contractName, 
+            string requiredTypeIdentity,
+            IEnumerable<KeyValuePair<string, Type>> requiredMetadata,
+            ImportCardinality cardinality, 
+            bool isRecomposable, 
+            bool isPrerequisite, 
+            CreationPolicy requiredCreationPolicy,
+            IDictionary<string, object> metadata,
+            ICompositionElement origin)
+            : base(contractName, requiredTypeIdentity, requiredMetadata, cardinality, isRecomposable, isPrerequisite, requiredCreationPolicy, metadata)
+        {
+            this._origin = origin;
+        }
+
+        string ICompositionElement.DisplayName
+        {
+            get { return this.GetDisplayName(); }
+        }
+
+        ICompositionElement ICompositionElement.Origin
+        {
+            get { return this._origin; }
+        }
+
+        public abstract ImportingItem ToImportingItem();
+
+        protected abstract string GetDisplayName();
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionItem.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionItem.cs
new file mode 100644
index 00000000000..3d649af1e0c
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionItem.cs
@@ -0,0 +1,16 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Reflection;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal abstract class ReflectionItem
+    {
+        public abstract string Name { get; }
+        public abstract string GetDisplayName();
+        public abstract Type ReturnType { get; }
+        public abstract ReflectionItemType ItemType { get; }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionItemType.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionItemType.cs
new file mode 100644
index 00000000000..2e7eaf4eba4
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionItemType.cs
@@ -0,0 +1,16 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal enum ReflectionItemType : int
+    {
+        Parameter = 0,
+        Field = 1,
+        Property = 2,
+        Method = 3,
+        Type = 4,
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMember.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMember.cs
new file mode 100644
index 00000000000..c34abc5b56a
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMember.cs
@@ -0,0 +1,42 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Reflection;
+using Microsoft.Internal;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal abstract class ReflectionMember : ReflectionItem
+    {
+        public abstract bool CanRead
+        {
+            get;
+        }
+        
+        public Type DeclaringType
+        {
+            get { return this.UnderlyingMember.DeclaringType; }
+        }
+
+        public override string Name
+        {
+            get { return this.UnderlyingMember.Name; }
+        }
+
+        public override string GetDisplayName()
+        {
+            return this.UnderlyingMember.GetDisplayName();
+        }
+
+        public abstract bool RequiresInstance
+        {
+            get;
+        }
+
+        public abstract MemberInfo UnderlyingMember { get; }
+
+        public abstract object GetValue(object instance);
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMemberExportDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMemberExportDefinition.cs
new file mode 100644
index 00000000000..04e51d64953
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMemberExportDefinition.cs
@@ -0,0 +1,93 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Hosting;
+using System.ComponentModel.Composition.Primitives;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Globalization;
+using System.Reflection;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class ReflectionMemberExportDefinition : ExportDefinition, ICompositionElement
+    {
+        private readonly LazyMemberInfo _member;
+        private readonly ExportDefinition _exportDefinition;
+        private readonly ICompositionElement _origin;
+        private IDictionary<string, object> _metadata;
+
+        public ReflectionMemberExportDefinition(LazyMemberInfo member, ExportDefinition exportDefinition, ICompositionElement origin)
+        {
+            Assumes.NotNull(exportDefinition);
+
+            this._member = member;
+            this._exportDefinition = exportDefinition;
+            this._origin = origin;
+        }
+
+        public override string ContractName
+        {
+            get { return this._exportDefinition.ContractName; }
+        }
+
+        public LazyMemberInfo ExportingLazyMember
+        {
+            get { return this._member; }
+        }
+
+        public override IDictionary<string, object> Metadata
+        {
+            get
+            {
+                if (this._metadata == null)
+                {
+                    this._metadata = this._exportDefinition.Metadata.AsReadOnly();
+                }
+                return this._metadata;
+            }
+        }
+
+        string ICompositionElement.DisplayName
+        {
+            get { return this.GetDisplayName(); }
+        }
+
+        ICompositionElement ICompositionElement.Origin
+        {
+            get { return this._origin; }
+        }
+
+        public override string ToString()
+        {
+            return this.GetDisplayName();
+        }
+
+        public int GetIndex()
+        {
+            return this.ExportingLazyMember.ToReflectionMember().UnderlyingMember.MetadataToken;
+        }
+
+        public ExportingMember ToExportingMember()
+        {
+            return new ExportingMember(this, this.ToReflectionMember());
+        }
+
+        private ReflectionMember ToReflectionMember()
+        {
+            return this.ExportingLazyMember.ToReflectionMember();
+        }
+
+        private string GetDisplayName()
+        {
+            return string.Format(CultureInfo.CurrentCulture,
+                   "{0} (ContractName=\"{1}\")",    // NOLOC
+                   this.ToReflectionMember().GetDisplayName(),
+                   this.ContractName);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMemberImportDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMemberImportDefinition.cs
new file mode 100644
index 00000000000..9d958ae46ac
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMemberImportDefinition.cs
@@ -0,0 +1,58 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Globalization;
+using System.Reflection;
+using Microsoft.Internal;
+using Microsoft.Internal.Collections;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class ReflectionMemberImportDefinition : ReflectionImportDefinition
+    {
+        private LazyMemberInfo _importingLazyMember;
+
+        public ReflectionMemberImportDefinition(
+            LazyMemberInfo importingLazyMember,
+            string contractName, 
+            string requiredTypeIdentity,
+            IEnumerable<KeyValuePair<string, Type>> requiredMetadata,
+            ImportCardinality cardinality, 
+            bool isRecomposable, 
+            bool isPrerequisite,
+            CreationPolicy requiredCreationPolicy,
+            IDictionary<string, object> metadata,
+            ICompositionElement origin) 
+            : base(contractName, requiredTypeIdentity, requiredMetadata, cardinality, isRecomposable, isPrerequisite, requiredCreationPolicy, metadata, origin)
+        {
+            Assumes.NotNull(contractName);
+
+            this._importingLazyMember = importingLazyMember;
+        }
+
+        public override ImportingItem ToImportingItem()
+        {
+            ReflectionWritableMember member = this.ImportingLazyMember.ToReflectionWriteableMember();
+            return new ImportingMember(this, member, new ImportType(member.ReturnType, this.Cardinality));
+        }
+
+        public LazyMemberInfo ImportingLazyMember
+        {
+            get { return this._importingLazyMember; } 
+        }
+
+        protected override string GetDisplayName()
+        {
+            return string.Format(
+                CultureInfo.CurrentCulture,
+                "{0} (ContractName=\"{1}\")",    // NOLOC
+                this.ImportingLazyMember.ToReflectionMember().GetDisplayName(),
+                this.ContractName);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMethod.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMethod.cs
new file mode 100644
index 00000000000..8ed39392c61
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionMethod.cs
@@ -0,0 +1,71 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.Hosting;
+using System.Reflection;
+using Microsoft.Internal;
+using System.Threading;
+using System.ComponentModel.Composition.Primitives;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal partial class ReflectionMethod : ReflectionMember
+    {
+        private readonly MethodInfo _method;
+
+        public ReflectionMethod(MethodInfo method)
+        {
+            Assumes.NotNull(method);
+
+            this._method = method;
+        }
+
+        public MethodInfo UnderlyingMethod
+        {
+            get { return this._method; }
+        }
+
+        public override MemberInfo UnderlyingMember
+        {
+            get { return this.UnderlyingMethod; }
+        }
+
+        public override bool CanRead
+        {
+            get { return true; }
+        }
+
+        public override bool RequiresInstance
+        {
+            get { return !this.UnderlyingMethod.IsStatic; }
+        }
+
+        public override Type ReturnType
+        {
+            get { return this.UnderlyingMethod.ReturnType; }
+        }
+
+        public override ReflectionItemType ItemType
+        {
+            get { return ReflectionItemType.Method; }
+        }
+
+        public override object GetValue(object instance)
+        {
+            return SafeCreateExportedDelegate(instance, _method);
+        }
+
+#if FEATURE_CAS_APTCA
+        [System.Security.SecuritySafeCritical]
+#endif //FEATURE_CAS_APTCA
+        private static ExportedDelegate SafeCreateExportedDelegate(object instance, MethodInfo method)
+        {
+            // We demand member access in place of the [SecurityCritical] 
+            // attribute on ExportDelegate constructor
+            ReflectionInvoke.DemandMemberAccessIfNeeded(method);
+
+            return new ExportedDelegate(instance, method);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionModelServices.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionModelServices.cs
new file mode 100644
index 00000000000..e781bfe3494
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionModelServices.cs
@@ -0,0 +1,500 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.Linq;
+using System.Reflection;
+using Microsoft.Internal;
+using System.Diagnostics.Contracts;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+#if FEATURE_CAS_APTCA
+    [System.Security.SecurityCritical]
+#endif //FEATURE_CAS_APTCA
+    public static class ReflectionModelServices
+    {
+        public static Lazy<Type> GetPartType(ComposablePartDefinition partDefinition)
+        {
+            Requires.NotNull(partDefinition, "partDefinition");
+            Contract.Ensures(Contract.Result<Lazy<Type>>() != null);
+
+            ReflectionComposablePartDefinition reflectionPartDefinition = partDefinition as ReflectionComposablePartDefinition;
+            if (reflectionPartDefinition == null)
+            {
+                throw ExceptionBuilder.CreateReflectionModelInvalidPartDefinition("partDefinition", partDefinition.GetType());
+            }
+
+            return reflectionPartDefinition.GetLazyPartType();
+        }
+
+        public static bool IsDisposalRequired(ComposablePartDefinition partDefinition)
+        {
+            Requires.NotNull(partDefinition, "partDefinition");
+
+            ReflectionComposablePartDefinition reflectionPartDefinition = partDefinition as ReflectionComposablePartDefinition;
+            if (reflectionPartDefinition == null)
+            {
+                throw ExceptionBuilder.CreateReflectionModelInvalidPartDefinition("partDefinition", partDefinition.GetType());
+            }
+
+            return reflectionPartDefinition.IsDisposalRequired;
+        }
+
+        public static LazyMemberInfo GetExportingMember(ExportDefinition exportDefinition)
+        {
+            Requires.NotNull(exportDefinition, "exportDefinition");
+
+            ReflectionMemberExportDefinition reflectionExportDefinition = exportDefinition as ReflectionMemberExportDefinition;
+            if (reflectionExportDefinition == null)
+            {
+                throw new ArgumentException(
+                    string.Format(CultureInfo.CurrentCulture, Strings.ReflectionModel_InvalidExportDefinition, exportDefinition.GetType()),
+                    "exportDefinition");
+            }
+
+            return reflectionExportDefinition.ExportingLazyMember;
+        }
+
+        public static LazyMemberInfo GetImportingMember(ImportDefinition importDefinition)
+        {
+            Requires.NotNull(importDefinition, "importDefinition");
+
+            ReflectionMemberImportDefinition reflectionMemberImportDefinition = importDefinition as ReflectionMemberImportDefinition;
+            if (reflectionMemberImportDefinition == null)
+            {
+                throw new ArgumentException(
+                    string.Format(CultureInfo.CurrentCulture, Strings.ReflectionModel_InvalidMemberImportDefinition, importDefinition.GetType()),
+                    "importDefinition");
+            }
+
+            return reflectionMemberImportDefinition.ImportingLazyMember;
+        }
+
+        public static Lazy<ParameterInfo> GetImportingParameter(ImportDefinition importDefinition)
+        {
+            Requires.NotNull(importDefinition, "importDefinition");
+            Contract.Ensures(Contract.Result<Lazy<ParameterInfo>>() != null);
+
+            ReflectionParameterImportDefinition reflectionParameterImportDefinition = importDefinition as ReflectionParameterImportDefinition;
+            if (reflectionParameterImportDefinition == null)
+            {
+                throw new ArgumentException(
+                    string.Format(CultureInfo.CurrentCulture, Strings.ReflectionModel_InvalidParameterImportDefinition, importDefinition.GetType()),
+                    "importDefinition");
+            }
+
+            return reflectionParameterImportDefinition.ImportingLazyParameter;
+        }
+
+        public static bool IsImportingParameter(ImportDefinition importDefinition)
+        {
+            Requires.NotNull(importDefinition, "importDefinition");
+
+            ReflectionImportDefinition reflectionImportDefinition = importDefinition as ReflectionImportDefinition;
+            if (reflectionImportDefinition == null)
+            {
+                throw new ArgumentException(
+                    string.Format(CultureInfo.CurrentCulture, Strings.ReflectionModel_InvalidImportDefinition, importDefinition.GetType()),
+                    "importDefinition");
+            }
+
+            return (importDefinition is ReflectionParameterImportDefinition);
+        }
+
+        public static bool IsExportFactoryImportDefinition(ImportDefinition importDefinition)
+        {
+            Requires.NotNull(importDefinition, "importDefinition");
+
+            ReflectionImportDefinition reflectionImportDefinition = importDefinition as ReflectionImportDefinition;
+            if (reflectionImportDefinition == null)
+            {
+                throw new ArgumentException(
+                    string.Format(CultureInfo.CurrentCulture, Strings.ReflectionModel_InvalidImportDefinition, importDefinition.GetType()),
+                    "importDefinition");
+            }
+
+            return (importDefinition is IPartCreatorImportDefinition);
+        }
+
+        public static ContractBasedImportDefinition GetExportFactoryProductImportDefinition(ImportDefinition importDefinition)
+        {
+            Requires.NotNull(importDefinition, "importDefinition");
+            Contract.Ensures(Contract.Result<ContractBasedImportDefinition>() != null);
+
+            IPartCreatorImportDefinition partCreatorImportDefinition = importDefinition as IPartCreatorImportDefinition;
+            if (partCreatorImportDefinition == null)
+            {
+                throw new ArgumentException(
+                    string.Format(CultureInfo.CurrentCulture, Strings.ReflectionModel_InvalidImportDefinition, importDefinition.GetType()),
+                    "importDefinition");
+            }
+
+            return partCreatorImportDefinition.ProductImportDefinition;
+        }
+
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public static ComposablePartDefinition CreatePartDefinition(
+            Lazy<Type> partType,
+            bool isDisposalRequired,
+            Lazy<IEnumerable<ImportDefinition>> imports,
+            Lazy<IEnumerable<ExportDefinition>> exports,
+            Lazy<IDictionary<string, object>> metadata,
+            ICompositionElement origin)
+        {
+            Requires.NotNull(partType, "partType");
+            Contract.Ensures(Contract.Result<ComposablePartDefinition>() != null);
+
+            return new ReflectionComposablePartDefinition(
+                new ReflectionPartCreationInfo(
+                    partType,
+                    isDisposalRequired,
+                    imports,
+                    exports,
+                    metadata,
+                    origin));
+        }
+
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public static ExportDefinition CreateExportDefinition(
+            LazyMemberInfo exportingMember,
+            string contractName,
+            Lazy<IDictionary<string, object>> metadata,
+            ICompositionElement origin)
+        {
+            Requires.NotNullOrEmpty(contractName, "contractName");
+            Requires.IsInMembertypeSet(exportingMember.MemberType, "exportingMember", MemberTypes.Field | MemberTypes.Property | MemberTypes.NestedType | MemberTypes.TypeInfo | MemberTypes.Method);
+            Contract.Ensures(Contract.Result<ExportDefinition>() != null);
+
+            return new ReflectionMemberExportDefinition(
+                exportingMember,
+                new LazyExportDefinition(contractName, metadata),
+                origin);
+        }
+
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public static ContractBasedImportDefinition CreateImportDefinition(
+            LazyMemberInfo importingMember,
+            string contractName,
+            string requiredTypeIdentity,
+            IEnumerable<KeyValuePair<string, Type>> requiredMetadata,
+            ImportCardinality cardinality,
+            bool isRecomposable,
+            CreationPolicy requiredCreationPolicy,
+            ICompositionElement origin)
+        {
+            return CreateImportDefinition(importingMember, contractName, requiredTypeIdentity, requiredMetadata, cardinality, isRecomposable, requiredCreationPolicy, MetadataServices.EmptyMetadata, false, origin);
+        }
+
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public static ContractBasedImportDefinition CreateImportDefinition(
+            LazyMemberInfo importingMember,
+            string contractName,
+            string requiredTypeIdentity,
+            IEnumerable<KeyValuePair<string, Type>> requiredMetadata,
+            ImportCardinality cardinality,
+            bool isRecomposable,
+            CreationPolicy requiredCreationPolicy,
+            IDictionary<string, object> metadata,
+            bool isExportFactory,
+            ICompositionElement origin)
+        {
+            return CreateImportDefinition(
+                importingMember,
+                contractName,
+                requiredTypeIdentity,
+                requiredMetadata,
+                cardinality,
+                isRecomposable,
+                false,
+                requiredCreationPolicy,
+                metadata,
+                isExportFactory,
+                origin);
+        }
+
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public static ContractBasedImportDefinition CreateImportDefinition(
+            LazyMemberInfo importingMember,
+            string contractName,
+            string requiredTypeIdentity,
+            IEnumerable<KeyValuePair<string, Type>> requiredMetadata,
+            ImportCardinality cardinality,
+            bool isRecomposable,
+            bool isPreRequisite,
+            CreationPolicy requiredCreationPolicy,
+            IDictionary<string, object> metadata,
+            bool isExportFactory,
+            ICompositionElement origin)
+        {
+            Requires.NotNullOrEmpty(contractName, "contractName");
+            Requires.IsInMembertypeSet(importingMember.MemberType, "importingMember", MemberTypes.Property | MemberTypes.Field);
+            Contract.Ensures(Contract.Result<ContractBasedImportDefinition>() != null);
+
+            if (isExportFactory)
+            {
+                return new PartCreatorMemberImportDefinition(
+                    importingMember,
+                    origin,
+                    new ContractBasedImportDefinition(
+                        contractName,
+                        requiredTypeIdentity,
+                        requiredMetadata,
+                        cardinality,
+                        isRecomposable,
+                        isPreRequisite,
+                        CreationPolicy.NonShared,
+                        metadata));
+            }
+            else
+            {
+                return new ReflectionMemberImportDefinition(
+                    importingMember,
+                    contractName,
+                    requiredTypeIdentity,
+                    requiredMetadata,
+                    cardinality,
+                    isRecomposable,
+                    isPreRequisite,
+                    requiredCreationPolicy,
+                    metadata,
+                    origin);
+            }
+        }
+
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public static ContractBasedImportDefinition CreateImportDefinition(
+            Lazy<ParameterInfo> parameter,
+            string contractName,
+            string requiredTypeIdentity,
+            IEnumerable<KeyValuePair<string, Type>> requiredMetadata,
+            ImportCardinality cardinality,
+            CreationPolicy requiredCreationPolicy,
+            ICompositionElement origin)
+        {
+            return CreateImportDefinition(parameter, contractName, requiredTypeIdentity, requiredMetadata, cardinality, requiredCreationPolicy, MetadataServices.EmptyMetadata, false, origin);
+        }
+
+        [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures")]
+        public static ContractBasedImportDefinition CreateImportDefinition(
+            Lazy<ParameterInfo> parameter,
+            string contractName,
+            string requiredTypeIdentity,
+            IEnumerable<KeyValuePair<string, Type>> requiredMetadata,
+            ImportCardinality cardinality,
+            CreationPolicy requiredCreationPolicy,
+            IDictionary<string, object> metadata,
+            bool isExportFactory,
+            ICompositionElement origin)
+        {
+            Requires.NotNull(parameter, "parameter");
+            Requires.NotNullOrEmpty(contractName, "contractName");
+            Contract.Ensures(Contract.Result<ContractBasedImportDefinition>() != null);
+
+            if (isExportFactory)
+            {
+                return new PartCreatorParameterImportDefinition(
+                    parameter,
+                    origin,
+                    new ContractBasedImportDefinition(
+                        contractName,
+                        requiredTypeIdentity,
+                        requiredMetadata,
+                        cardinality,
+                        false,
+                        true,
+                        CreationPolicy.NonShared,
+                        metadata));
+            }
+            else
+            {
+                return new ReflectionParameterImportDefinition(
+                    parameter,
+                    contractName,
+                    requiredTypeIdentity,
+                    requiredMetadata,
+                    cardinality,
+                    requiredCreationPolicy,
+                    metadata,
+                    origin);
+            }
+        }
+
+        public static bool TryMakeGenericPartDefinition(ComposablePartDefinition partDefinition, IEnumerable<Type> genericParameters, out ComposablePartDefinition specialization)
+        {
+            Requires.NotNull(partDefinition, "partDefinition");
+
+            specialization = null;
+            ReflectionComposablePartDefinition reflectionPartDefinition = partDefinition as ReflectionComposablePartDefinition;
+            if (reflectionPartDefinition == null)
+            {
+                throw ExceptionBuilder.CreateReflectionModelInvalidPartDefinition("partDefinition", partDefinition.GetType());
+            }
+
+            return reflectionPartDefinition.TryMakeGenericPartDefinition(genericParameters.ToArray(), out specialization);
+        }
+    }
+
+
+
+    internal class ReflectionPartCreationInfo : IReflectionPartCreationInfo
+    {
+        private readonly Lazy<Type> _partType;
+        private readonly Lazy<IEnumerable<ImportDefinition>> _imports;
+        private readonly Lazy<IEnumerable<ExportDefinition>> _exports;
+        private readonly Lazy<IDictionary<string, object>> _metadata;
+        private readonly ICompositionElement _origin;
+        private ConstructorInfo _constructor;
+        private bool _isDisposalRequired;
+
+        public ReflectionPartCreationInfo(
+            Lazy<Type> partType,
+            bool isDisposalRequired,
+            Lazy<IEnumerable<ImportDefinition>> imports,
+            Lazy<IEnumerable<ExportDefinition>> exports,
+            Lazy<IDictionary<string, object>> metadata,
+            ICompositionElement origin)
+        {
+            Assumes.NotNull(partType);
+
+            this._partType = partType;
+            this._isDisposalRequired = isDisposalRequired;
+            this._imports = imports;
+            this._exports = exports;
+            this._metadata = metadata;
+            this._origin = origin;
+        }
+
+        public Type GetPartType()
+        {
+            return this._partType.GetNotNullValue("type");
+        }
+
+        public Lazy<Type> GetLazyPartType()
+        {
+            return this._partType;
+        }
+
+        public ConstructorInfo GetConstructor()
+        {
+            if (this._constructor == null)
+            {
+                ConstructorInfo[] constructors = null;
+                constructors = this.GetImports()
+                    .OfType<ReflectionParameterImportDefinition>()
+                    .Select(parameterImport => parameterImport.ImportingLazyParameter.Value.Member)
+                    .OfType<ConstructorInfo>()
+                    .Distinct()
+                    .ToArray();
+
+                if (constructors.Length == 1)
+                {
+                    this._constructor = constructors[0];
+                }
+                else if (constructors.Length == 0)
+                {
+                    this._constructor = this.GetPartType().GetConstructor(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance, null, Type.EmptyTypes, null);
+                }
+            }
+            return this._constructor;
+        }
+
+        public bool IsDisposalRequired
+        {
+            get
+            {
+                return this._isDisposalRequired;
+            }
+        }
+
+        public IDictionary<string, object> GetMetadata()
+        {
+            return (this._metadata != null) ? this._metadata.Value : null;
+        }
+
+        public IEnumerable<ExportDefinition> GetExports()
+        {
+            if (this._exports == null)
+            {
+                yield break;
+            }
+
+            IEnumerable<ExportDefinition> exports = this._exports.Value;
+
+            if (exports == null)
+            {
+                yield break;
+            }
+
+            foreach (ExportDefinition export in exports)
+            {
+                ReflectionMemberExportDefinition reflectionExport = export as ReflectionMemberExportDefinition;
+                if (reflectionExport == null)
+                {
+                    throw new InvalidOperationException(
+                        string.Format(CultureInfo.CurrentCulture, Strings.ReflectionModel_InvalidExportDefinition, export.GetType()));
+                }
+                yield return reflectionExport;
+            }
+        }
+
+        public IEnumerable<ImportDefinition> GetImports()
+        {
+            if (this._imports == null)
+            {
+                yield break;
+            }
+
+            IEnumerable<ImportDefinition> imports = this._imports.Value;
+
+            if (imports == null)
+            {
+                yield break;
+            }
+
+            foreach (ImportDefinition import in imports)
+            {
+                ReflectionImportDefinition reflectionImport = import as ReflectionImportDefinition;
+                if (reflectionImport == null)
+                {
+                    throw new InvalidOperationException(
+                        string.Format(CultureInfo.CurrentCulture, Strings.ReflectionModel_InvalidMemberImportDefinition, import.GetType()));
+                }
+                yield return reflectionImport;
+            }
+        }
+
+        public string DisplayName
+        {
+            get { return this.GetPartType().GetDisplayName(); }
+        }
+
+        public ICompositionElement Origin
+        {
+            get { return this._origin; }
+        }
+    }
+
+    internal class LazyExportDefinition : ExportDefinition
+    {
+        private readonly Lazy<IDictionary<string, object>> _metadata;
+
+        public LazyExportDefinition(string contractName, Lazy<IDictionary<string, object>> metadata)
+            : base(contractName, (IDictionary<string, object>)null)
+        {
+            this._metadata = metadata;
+        }
+
+        public override IDictionary<string, object> Metadata
+        {
+            get
+            {
+                return this._metadata.Value ?? MetadataServices.EmptyMetadata;
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionParameter.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionParameter.cs
new file mode 100644
index 00000000000..0d5fbf37621
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionParameter.cs
@@ -0,0 +1,52 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Globalization;
+using System.Reflection;
+using Microsoft.Internal;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class ReflectionParameter : ReflectionItem
+    {
+        private readonly ParameterInfo _parameter;
+
+        public ReflectionParameter(ParameterInfo parameter)
+        {
+            Assumes.NotNull(parameter);
+
+            this._parameter = parameter;
+        }
+
+        public ParameterInfo UnderlyingParameter
+        {
+            get { return this._parameter; }
+        }
+
+        public override string Name
+        {
+            get { return this.UnderlyingParameter.Name; }
+        }
+
+        public override string GetDisplayName()
+        {
+            return string.Format(
+                CultureInfo.CurrentCulture,
+                "{0} (Parameter=\"{1}\")",  // NOLOC
+                this.UnderlyingParameter.Member.GetDisplayName(),
+                this.UnderlyingParameter.Name);
+        }
+
+        public override Type ReturnType
+        {
+            get { return this.UnderlyingParameter.ParameterType; }
+        }
+
+        public override ReflectionItemType ItemType
+        {
+            get { return ReflectionItemType.Parameter; }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionParameterImportDefinition.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionParameterImportDefinition.cs
new file mode 100644
index 00000000000..36762a3795c
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionParameterImportDefinition.cs
@@ -0,0 +1,56 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Globalization;
+using System.Reflection;
+using Microsoft.Internal;
+using System.ComponentModel.Composition.ReflectionModel;
+using System.Collections.Generic;
+using System.ComponentModel.Composition.Primitives;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class ReflectionParameterImportDefinition : ReflectionImportDefinition
+    {
+        private Lazy<ParameterInfo> _importingLazyParameter;
+
+        public ReflectionParameterImportDefinition(
+            Lazy<ParameterInfo> importingLazyParameter,
+            string contractName, 
+            string requiredTypeIdentity,
+            IEnumerable<KeyValuePair<string,Type>> requiredMetadata,
+            ImportCardinality cardinality, 
+            CreationPolicy requiredCreationPolicy,
+            IDictionary<string, object> metadata,
+            ICompositionElement origin)
+            : base(contractName, requiredTypeIdentity, requiredMetadata, cardinality, false, true, requiredCreationPolicy, metadata, origin)
+        {
+            Assumes.NotNull(importingLazyParameter);
+
+            this._importingLazyParameter = importingLazyParameter;
+        }
+
+        public override ImportingItem ToImportingItem()
+        {
+            return new ImportingParameter(this, new ImportType(this.ImportingLazyParameter.GetNotNullValue("parameter").ParameterType, this.Cardinality));
+        }
+
+        public Lazy<ParameterInfo> ImportingLazyParameter
+        {
+            get { return this._importingLazyParameter; }
+        }
+
+        protected override string GetDisplayName()
+        {
+            ParameterInfo parameter = this.ImportingLazyParameter.GetNotNullValue("parameter");
+            return string.Format(
+                CultureInfo.CurrentCulture,
+                "{0} (Parameter=\"{1}\", ContractName=\"{2}\")",  // NOLOC
+                parameter.Member.GetDisplayName(),
+                parameter.Name,                
+                this.ContractName);
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionProperty.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionProperty.cs
new file mode 100644
index 00000000000..6daa34baa50
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionProperty.cs
@@ -0,0 +1,124 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Reflection;
+using Microsoft.Internal;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    // Instead of representing properties as an actual PropertyInfo, we need to 
+    // represent them as two MethodInfo objects one for each accessor. This is so 
+    // that cached attribute part can go from a metadata token -> XXXInfo without 
+    // needing to walk all members of a particular type. Unfortunately, (probably 
+    // because you never see one of them in an IL stream), Reflection does not allow 
+    // you to go from a metadata token -> PropertyInfo like it does with types, 
+    // fields, and methods.
+
+    internal class ReflectionProperty : ReflectionWritableMember
+    {
+        private readonly MethodInfo _getMethod;
+        private readonly MethodInfo _setMethod;
+
+        public ReflectionProperty(MethodInfo getMethod, MethodInfo setMethod)
+        {
+            Assumes.IsTrue(getMethod != null || setMethod != null);
+
+            this._getMethod = getMethod;
+            this._setMethod = setMethod;
+        }
+
+        public override MemberInfo UnderlyingMember
+        {
+            get { return this.UnderlyingGetMethod ?? this.UnderlyingSetMethod; }
+        }
+
+        public override bool CanRead
+        {
+            get { return this.UnderlyingGetMethod != null; }
+        }
+
+        public override bool CanWrite
+        {
+            get { return this.UnderlyingSetMethod != null; }
+        }
+
+        public MethodInfo UnderlyingGetMethod
+        {
+            get { return this._getMethod; }
+        }
+
+        public MethodInfo UnderlyingSetMethod
+        {
+            get { return this._setMethod; }
+        }
+
+        public override string Name
+        {
+            get
+            {
+                MethodInfo method = this.UnderlyingGetMethod ?? this.UnderlyingSetMethod;
+
+                string name = method.Name;
+
+                Assumes.IsTrue(name.Length > 4);
+
+                // Remove 'get_' or 'set_'
+                return name.Substring(4);
+            }
+        }
+
+        public override string GetDisplayName()
+        {
+            return ReflectionServices.GetDisplayName(this.DeclaringType, this.Name);
+        }
+
+        public override bool RequiresInstance
+        {
+            get
+            {
+                MethodInfo method = this.UnderlyingGetMethod ?? this.UnderlyingSetMethod;
+
+                return !method.IsStatic;
+            }
+        }
+
+        public override Type ReturnType
+        {
+            get
+            {
+                if (this.UnderlyingGetMethod != null)
+                {
+                    return this.UnderlyingGetMethod.ReturnType;
+                }
+
+                ParameterInfo[] parameters = this.UnderlyingSetMethod.GetParameters();
+
+                Assumes.IsTrue(parameters.Length > 0);
+
+                return parameters[parameters.Length - 1].ParameterType;
+            }
+        }
+
+        public override ReflectionItemType ItemType
+        {
+            get { return ReflectionItemType.Property; }
+        }
+
+        public override object GetValue(object instance)
+        {
+            Assumes.NotNull(this._getMethod);
+
+            return this.UnderlyingGetMethod.SafeInvoke(instance);
+        }
+
+        public override void SetValue(object instance, object value)
+        {
+            Assumes.NotNull(this._setMethod);
+
+            this.UnderlyingSetMethod.SafeInvoke(instance, value);
+        }
+
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionType.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionType.cs
new file mode 100644
index 00000000000..b6ff302dbaf
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionType.cs
@@ -0,0 +1,53 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.ComponentModel.Composition.AttributedModel;
+using System.Reflection;
+using Microsoft.Internal;
+using System.Threading;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal class ReflectionType : ReflectionMember
+    {
+        private Type _type;
+
+        public ReflectionType(Type type)
+        {
+            Assumes.NotNull(type);
+
+            this._type = type;
+        }
+
+        public override MemberInfo UnderlyingMember
+        {
+            get { return this._type; }
+        }
+
+        public override bool CanRead
+        {
+            get { return true; }
+        }
+
+        public override bool RequiresInstance
+        {
+            get { return true; }
+        }
+
+        public override Type ReturnType
+        {
+            get { return this._type; }
+        }
+
+        public override ReflectionItemType ItemType
+        {
+            get { return ReflectionItemType.Type; }
+        }
+
+        public override object GetValue(object instance)
+        {
+            return instance;
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionWritableMember.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionWritableMember.cs
new file mode 100644
index 00000000000..b8cf56d340d
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/ComponentModel/Composition/ReflectionModel/ReflectionWritableMember.cs
@@ -0,0 +1,19 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Reflection;
+using Microsoft.Internal;
+
+namespace System.ComponentModel.Composition.ReflectionModel
+{
+    internal abstract class ReflectionWritableMember : ReflectionMember
+    {
+        public abstract bool CanWrite
+        {
+            get;
+        }
+
+        public abstract void SetValue(object instance, object value);
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/LazyOfTTMetadata.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/LazyOfTTMetadata.cs
new file mode 100644
index 00000000000..aba65fb5a6a
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/System/LazyOfTTMetadata.cs
@@ -0,0 +1,62 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading;
+
+namespace System
+{
+    [Serializable]
+    public class Lazy<T, TMetadata> : Lazy<T>
+    {
+        private TMetadata _metadata;
+
+        public Lazy(Func<T> valueFactory, TMetadata metadata) : 
+            base(valueFactory)
+        {
+            this._metadata = metadata;
+        }
+
+        public Lazy(TMetadata metadata) :
+            base()
+        {
+            this._metadata = metadata;
+        }
+
+
+        public Lazy(TMetadata metadata, bool isThreadSafe) : 
+            base(isThreadSafe)
+        {
+            this._metadata = metadata;
+        }
+
+        public Lazy(Func<T> valueFactory, TMetadata metadata, bool isThreadSafe) :
+            base(valueFactory, isThreadSafe)
+        {
+            this._metadata = metadata;
+        }
+
+        public Lazy(TMetadata metadata, LazyThreadSafetyMode mode) :
+            base(mode)
+        {
+            this._metadata = metadata;
+        }
+
+        public Lazy(Func<T> valueFactory, TMetadata metadata, LazyThreadSafetyMode mode) :
+            base(valueFactory, mode)
+        {
+            this._metadata = metadata;
+        }
+
+        public TMetadata Metadata
+        {
+            get
+            {
+                return this._metadata;
+            }
+        }
+    }
+}
diff --git a/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/VersionInfo.cs b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/VersionInfo.cs
new file mode 100644
index 00000000000..1f7bf88888a
--- /dev/null
+++ b/mcs/class/System.ComponentModel.Composition.4.5/src/ComponentModel/VersionInfo.cs
@@ -0,0 +1,14 @@
+// -----------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+// -----------------------------------------------------------------------
+using System;
+using System.Runtime.CompilerServices;
+using System.Security;
+
+[assembly: System.Reflection.AssemblyTitle("System.ComponentModel.Composition.CodePlex")]
+[assembly: System.Reflection.AssemblyCopyright("(c) Microsoft Corporation. All rights reserved.")]
+[assembly: System.Reflection.AssemblyDescription("Codeplex version (http://mef.codeplex.com)")]
+[assembly: System.Reflection.AssemblyVersion("4.1.2.0")]
+[assembly: System.Reflection.AssemblyFileVersion("1.1.0.0")]
+
+