From a43e99ae2fbcd644460f245f471f573b7d3b66ec Mon Sep 17 00:00:00 2001
From: Glenn <5834289+glennawatson@users.noreply.github.com>
Date: Sat, 30 Oct 2021 19:24:14 +1100
Subject: [PATCH] fix: memory leak on WPF (#2986)

* fix: memory leak on WPF

* Update ActivationForViewFetcher.cs

* Update WpfActivationForViewFetcherTest.cs

* Update WpfActivationForViewFetcherTest.cs

* Update WpfActivationForViewFetcherTest.cs
---
 .../wpf/WpfActivationForViewFetcherTest.cs    | 54 -------------------
 .../ActivationForViewFetcher.cs               | 17 ------
 2 files changed, 71 deletions(-)

diff --git a/src/ReactiveUI.Tests/Platforms/wpf/WpfActivationForViewFetcherTest.cs b/src/ReactiveUI.Tests/Platforms/wpf/WpfActivationForViewFetcherTest.cs
index fc99631cf8..6f1b30e38e 100644
--- a/src/ReactiveUI.Tests/Platforms/wpf/WpfActivationForViewFetcherTest.cs
+++ b/src/ReactiveUI.Tests/Platforms/wpf/WpfActivationForViewFetcherTest.cs
@@ -5,8 +5,6 @@
 
 using System;
 using System.Reactive.Concurrency;
-using System.Threading;
-using System.Threading.Tasks;
 using System.Windows;
 
 using DynamicData;
@@ -42,58 +40,6 @@ public void FrameworkElementIsActivatedAndDeactivated()
             new[] { true, false }.AssertAreEqual(activated);
         }
 
-        [Fact]
-        public void WindowIsActivatedAndDeactivated()
-        {
-            var window = new WpfTestWindow();
-            var activation = new ActivationForViewFetcher();
-
-            var obs = activation.GetActivationForView(window);
-            obs.ToObservableChangeSet(scheduler: ImmediateScheduler.Instance).Bind(out var activated).Subscribe();
-
-            var loaded = new RoutedEventArgs();
-            loaded.RoutedEvent = FrameworkElement.LoadedEvent;
-
-            window.RaiseEvent(loaded);
-
-            new[] { true }.AssertAreEqual(activated);
-
-            window.Close();
-
-            new[] { true, false }.AssertAreEqual(activated);
-        }
-
-        [StaFact]
-        public void WindowAndFrameworkElementAreActivatedAndDeactivated()
-        {
-            var window = new WpfTestWindow();
-            var uc = new WpfTestUserControl();
-
-            window.RootGrid.Children.Add(uc);
-
-            var activation = new ActivationForViewFetcher();
-
-            var windowObs = activation.GetActivationForView(window);
-            windowObs.ToObservableChangeSet(scheduler: ImmediateScheduler.Instance).Bind(out var windowActivated).Subscribe();
-
-            var ucObs = activation.GetActivationForView(uc);
-            ucObs.ToObservableChangeSet(scheduler: ImmediateScheduler.Instance).Bind(out var controlActivated).Subscribe();
-
-            var loaded = new RoutedEventArgs();
-            loaded.RoutedEvent = FrameworkElement.LoadedEvent;
-
-            window.RaiseEvent(loaded);
-            uc.RaiseEvent(loaded);
-
-            new[] { true }.AssertAreEqual(windowActivated);
-            new[] { true }.AssertAreEqual(controlActivated);
-
-            window.Dispatcher.InvokeShutdown();
-
-            new[] { true, false }.AssertAreEqual(windowActivated);
-            new[] { true, false }.AssertAreEqual(controlActivated);
-        }
-
         [Fact]
         public void IsHitTestVisibleActivatesFrameworkElement()
         {
diff --git a/src/ReactiveUI.Wpf/ActivationForViewFetcher.cs b/src/ReactiveUI.Wpf/ActivationForViewFetcher.cs
index b07cff5592..b77815fa9d 100644
--- a/src/ReactiveUI.Wpf/ActivationForViewFetcher.cs
+++ b/src/ReactiveUI.Wpf/ActivationForViewFetcher.cs
@@ -58,13 +58,10 @@ public IObservable<bool> GetActivationForView(IActivatableView view)
 
             var windowActivation = GetActivationForWindow(view);
 
-            var dispatcherActivation = GetActivationForDispatcher(fe);
-
             return viewLoaded
                 .Merge(viewUnloaded)
                 .Merge(hitTestVisible)
                 .Merge(windowActivation)
-                .Merge(dispatcherActivation)
                 .DistinctUntilChanged();
         }
 
@@ -86,19 +83,5 @@ private static IObservable<bool> GetActivationForWindow(IActivatableView view)
 
             return viewClosed;
         }
-
-        private static IObservable<bool> GetActivationForDispatcher(DispatcherObject dispatcherObject)
-        {
-            var dispatcherShutdownStarted = Observable.FromEvent<EventHandler, bool>(
-                eventHandler =>
-                {
-                    void Handler(object? sender, EventArgs e) => eventHandler(false);
-                    return Handler;
-                },
-                x => dispatcherObject.Dispatcher.ShutdownStarted += x,
-                x => dispatcherObject.Dispatcher.ShutdownStarted -= x);
-
-            return dispatcherShutdownStarted;
-        }
     }
 }