Merge pull request #690 from reactiveui/really-fix-leak

Fix bug with deactivation.

Author: Paul Betts

ReactiveUI.Tests/ReactiveUI.Tests_Net45.csproj

@@ -114,6 +114,7 @@
     <Compile Include="Winforms\ReactiveBindingListTests.cs" />
     <Compile Include="Winforms\RoutedViewHostTests.cs" />
     <Compile Include="Winforms\ViewModelViewHostTests.cs" />
+    <Compile Include="Xaml\ActivationForViewFetcherTest.cs" />
     <Compile Include="Xaml\DependencyObjectObservableForPropertyTest.cs" />
     <Compile Include="ErrorsTest.cs" />
     <Compile Include="MessageBusTest.cs" />

ReactiveUI.Tests/Xaml/ActivationForViewFetcherTest.cs

@@ -0,0 +1,132 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows;
+using System.Windows.Controls;
+using Xunit;
+
+namespace ReactiveUI.Tests
+{
+    public class ActivationForViewFetcherTest
+    {
+        public class TestUserControl : UserControl, IActivatable
+        {
+            public TestUserControl()
+            {
+
+            }
+        }
+
+        [Fact]
+        public void FrameworkElementIsActivatedAndDeactivated()
+        {
+            var uc = new TestUserControl();
+            var activation = new ActivationForViewFetcher();
+
+            var obs = activation.GetActivationForView(uc);
+            var activated = obs.CreateCollection();
+
+            RoutedEventArgs loaded = new RoutedEventArgs();
+            loaded.RoutedEvent = FrameworkElement.LoadedEvent;
+
+            uc.RaiseEvent(loaded);
+
+            new[] { true }.AssertAreEqual(activated);
+
+            RoutedEventArgs unloaded = new RoutedEventArgs();
+            unloaded.RoutedEvent = FrameworkElement.UnloadedEvent;
+
+            uc.RaiseEvent(unloaded);
+
+            new[] { true, false }.AssertAreEqual(activated);
+        }
+
+        [Fact]
+        public void IsHitTestVisibleActivatesFrameworkElement()
+        {
+            var uc = new TestUserControl();
+            uc.IsHitTestVisible = false;
+            var activation = new ActivationForViewFetcher();
+
+            var obs = activation.GetActivationForView(uc);
+            var activated = obs.CreateCollection();
+
+            RoutedEventArgs loaded = new RoutedEventArgs();
+            loaded.RoutedEvent = FrameworkElement.LoadedEvent;
+
+            uc.RaiseEvent(loaded);
+
+            // IsHitTestVisible still false
+            new bool[0].AssertAreEqual(activated);
+
+            uc.IsHitTestVisible = true;
+
+            // IsHitTestVisible true
+            new[] { true }.AssertAreEqual(activated);
+
+            RoutedEventArgs unloaded = new RoutedEventArgs();
+            unloaded.RoutedEvent = FrameworkElement.UnloadedEvent;
+
+            uc.RaiseEvent(unloaded);
+
+            new[] { true, false }.AssertAreEqual(activated);
+        }
+
+        [Fact]
+        public void IsHitTestVisibleDeactivatesFrameworkElement()
+        {
+            var uc = new TestUserControl();
+            var activation = new ActivationForViewFetcher();
+
+            var obs = activation.GetActivationForView(uc);
+            var activated = obs.CreateCollection();
+
+            RoutedEventArgs loaded = new RoutedEventArgs();
+            loaded.RoutedEvent = FrameworkElement.LoadedEvent;
+
+            uc.RaiseEvent(loaded);
+
+            new[] { true }.AssertAreEqual(activated);
+
+            uc.IsHitTestVisible = false;
+
+            new[] { true, false }.AssertAreEqual(activated);
+        }
+
+        [Fact]
+        public void FrameworkElementIsActivatedAndDeactivatedWithHitTest()
+        {
+            var uc = new TestUserControl();
+            var activation = new ActivationForViewFetcher();
+
+            var obs = activation.GetActivationForView(uc);
+            var activated = obs.CreateCollection();
+
+            RoutedEventArgs loaded = new RoutedEventArgs();
+            loaded.RoutedEvent = FrameworkElement.LoadedEvent;
+
+            uc.RaiseEvent(loaded);
+
+            new[] { true }.AssertAreEqual(activated);
+
+            // this should deactivate it
+            uc.IsHitTestVisible = false;
+
+            new[] { true, false }.AssertAreEqual(activated);
+
+            // this should activate it
+            uc.IsHitTestVisible = true;
+
+            new[] { true, false, true }.AssertAreEqual(activated);
+
+            RoutedEventArgs unloaded = new RoutedEventArgs();
+            unloaded.RoutedEvent = FrameworkElement.UnloadedEvent;
+
+            uc.RaiseEvent(unloaded);
+
+            new[] { true, false, true, false }.AssertAreEqual(activated);
+        }
+    }
+}

ReactiveUI/Xaml/ActivationForViewFetcher.cs

@@ -36,7 +36,7 @@ public IObservable<bool> GetActivationForView(IActivatable view)
 
             return viewLoaded
                 .Merge(viewUnloaded)
-                .Select(b => b ? fe.WhenAnyValue(x => x.IsHitTestVisible).Where(hv => hv && b) : Observable.Empty<bool>())
+                .Select(b => b ? fe.WhenAnyValue(x => x.IsHitTestVisible).Select(hv => hv && b).SkipWhile(x => !x) : Observable.Return(b))
                 .Switch()
                 .DistinctUntilChanged();
         }