Merge pull request #381 from xamarin/ermau-fix-collection-editor-switch

[Core] Handle no-editors in CollectionPropertyViewModel

2 files changed, 31 insertions, 0 deletions

diff --git a/Xamarin.PropertyEditing.Tests/CollectionPropertyViewModelTests.cs b/Xamarin.PropertyEditing.Tests/CollectionPropertyViewModelTests.cs
index 0139aad..7f87448 100644
--- a/Xamarin.PropertyEditing.Tests/CollectionPropertyViewModelTests.cs
+++ b/Xamarin.PropertyEditing.Tests/CollectionPropertyViewModelTests.cs
@@ -158,6 +158,28 @@ namespace Xamarin.PropertyEditing.Tests
 		}
 
 		[Test]
+		public async Task RemoveEditor ()
+		{
+			TargetPlatform platform = new TargetPlatform (new MockEditorProvider ());
+
+			var obj = new {
+				Collection = new ArrayList ()
+			};
+
+			var editor = new ReflectionObjectEditor (obj);
+
+			var vm = new CollectionPropertyViewModel (platform, editor.Properties.First (), new[] { editor });
+			await vm.AssignableTypes.Task;
+
+			vm.Editors.Remove (editor);
+			await vm.AssignableTypes.Task;
+
+			Assert.That (vm.AssignableTypes.Value, Is.Empty);
+			Assert.That (vm.SuggestedTypes, Is.Empty);
+			Assert.That (vm.SelectedType, Is.Null);
+		}
+
+		[Test]
 		public async Task MoveUpCommand ()
 		{
 			TargetPlatform platform = new TargetPlatform (new MockEditorProvider());
diff --git a/Xamarin.PropertyEditing/ViewModels/CollectionPropertyViewModel.cs b/Xamarin.PropertyEditing/ViewModels/CollectionPropertyViewModel.cs
index 641e19e..080a93a 100644
--- a/Xamarin.PropertyEditing/ViewModels/CollectionPropertyViewModel.cs
+++ b/Xamarin.PropertyEditing/ViewModels/CollectionPropertyViewModel.cs
@@ -317,6 +317,15 @@ namespace Xamarin.PropertyEditing.ViewModels
 			if (Property == null)
 				return;
 
+			if (Editors.Count == 0) {
+				SuggestedTypes = new ObservableCollectionEx<ITypeInfo> ();
+				AssignableTypes = new AsyncValue<IReadOnlyDictionary<IAssemblyInfo, ILookup<string, ITypeInfo>>> (
+					Task.FromResult<IReadOnlyDictionary<IAssemblyInfo, ILookup<string, ITypeInfo>>> (
+						new Dictionary<IAssemblyInfo, ILookup<string, ITypeInfo>> ()));
+				SelectedType = null;
+				return;
+			}
+
 			var types = Editors.GetCommonAssignableTypes (Property, childTypes: true);
 			var assignableTypesTask = types.ContinueWith (t => t.Result.GetTypeTree (), TaskScheduler.Default);
 			AssignableTypes = new AsyncValue<IReadOnlyDictionary<IAssemblyInfo, ILookup<string, ITypeInfo>>> (assignableTypesTask);