Merge pull request #123 from frogger3d/feature/async-interaction-request

Add an async version of InteractionRequest<T>.Raise

4 files changed, 54 insertions, 0 deletions

diff --git a/Source/Wpf/Prism.Wpf.Tests/Interactivity/InteractionRequestTriggerFixture.cs b/Source/Wpf/Prism.Wpf.Tests/Interactivity/InteractionRequestTriggerFixture.cs
index c9fcb79..5043de5 100644
--- a/Source/Wpf/Prism.Wpf.Tests/Interactivity/InteractionRequestTriggerFixture.cs
+++ b/Source/Wpf/Prism.Wpf.Tests/Interactivity/InteractionRequestTriggerFixture.cs
@@ -5,6 +5,7 @@ using System.Windows;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Prism.Interactivity.InteractionRequest;
 using Prism.Wpf.Tests.Mocks;
+using System.Threading.Tasks;
 
 namespace Prism.Wpf.Tests.Interactivity
 {
@@ -46,6 +47,26 @@ namespace Prism.Wpf.Tests.Interactivity
             request.Raise(new Notification());
             Assert.IsTrue(action.ExecutionCount == 1);
         }
+
+        [TestMethod]
+        public async Task WhenEventIsRaisedAsync_NotificationIsPassedBackAsync()
+        {
+            var request = new InteractionRequest<INotification>();
+            var trigger = new TestableInteractionRequestTrigger();
+            var associatedObject = new DependencyObject();
+            var action = new TestableTriggerAction();
+            var notification = new Notification();
+
+            trigger.Actions.Add(action);
+            trigger.Attach(associatedObject);
+            trigger.SourceObject = request;
+
+            Assert.IsTrue(action.ExecutionCount == 0);
+
+            var result = await request.RaiseAsync(notification);
+            Assert.IsTrue(action.ExecutionCount == 1);
+            Assert.ReferenceEquals(notification, result);
+        }
     }
 
     public class TestableInteractionRequestTrigger : InteractionRequestTrigger
@@ -66,6 +87,10 @@ namespace Prism.Wpf.Tests.Interactivity
         protected override void Invoke(object parameter)
         {
             this.ExecutionCount++;
+            if (parameter is InteractionRequestedEventArgs)
+            {
+                ((InteractionRequestedEventArgs)parameter).Callback();
+            }
         }
     }
 }
diff --git a/Source/Wpf/Prism.Wpf/Common/CallbackHelper.cs b/Source/Wpf/Prism.Wpf/Common/CallbackHelper.cs
new file mode 100644
index 0000000..28cdaa0
--- /dev/null
+++ b/Source/Wpf/Prism.Wpf/Common/CallbackHelper.cs
@@ -0,0 +1,15 @@
+using System;
+using System.Threading.Tasks;
+
+namespace Prism.Common
+{
+    internal static class CallbackHelper
+    {
+        public static async Task<TResult> AwaitCallbackResult<TResult>(Action<Action<TResult>> f)
+        {
+            var tcs = new TaskCompletionSource<TResult>();
+            f(n => tcs.SetResult(n));
+            return await tcs.Task;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Source/Wpf/Prism.Wpf/Interactivity/InteractionRequest/InteractionRequest.cs b/Source/Wpf/Prism.Wpf/Interactivity/InteractionRequest/InteractionRequest.cs
index ce42e0c..9138dd1 100644
--- a/Source/Wpf/Prism.Wpf/Interactivity/InteractionRequest/InteractionRequest.cs
+++ b/Source/Wpf/Prism.Wpf/Interactivity/InteractionRequest/InteractionRequest.cs
@@ -1,6 +1,8 @@
 
 
 using System;
+using System.Threading.Tasks;
+using Prism.Common;
 
 namespace Prism.Interactivity.InteractionRequest
 {
@@ -39,5 +41,16 @@ namespace Prism.Interactivity.InteractionRequest
                 handler(this, new InteractionRequestedEventArgs(context, () => { if(callback != null) callback(context); } ));
             }
         }
+
+        /// <summary>
+        /// Fires the Raised event asynchronously. Please note that this request may never return
+        /// if the InteractionRequest is unhandled.
+        /// </summary>
+        /// <param name="context">The context for the interaction request.</param>
+        /// <returns>The context after the request has been handled by the UI.</returns>
+        public async Task<T> RaiseAsync(T context)
+        {
+            return await CallbackHelper.AwaitCallbackResult<T>(callback => this.Raise(context, callback));
+        }
     }
 }
diff --git a/Source/Wpf/Prism.Wpf/Prism.Wpf.csproj b/Source/Wpf/Prism.Wpf/Prism.Wpf.csproj
index a51ec4f..8157b11 100644
--- a/Source/Wpf/Prism.Wpf/Prism.Wpf.csproj
+++ b/Source/Wpf/Prism.Wpf/Prism.Wpf.csproj
@@ -54,6 +54,7 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Bootstrapper.cs" />
+    <Compile Include="Common\CallbackHelper.cs" />
     <Compile Include="Common\MvvmHelpers.cs" />
     <Compile Include="Extensions\CollectionExtensions.cs" />
     <Compile Include="Events\WeakDelegatesManager.cs" />