[Windows] Fix issue with caching the page that holds unfocused control (

#13028) * [Windows] Fix issue with caching the page that holds unfocused control * Simplify condition * [test] Use AutoResetEvent for entry focus test * Use tabStop to unfocus
dotnet · Feb 10, 2023 · c1aac2e · c1aac2e
1 parent 78f133c
commit c1aac2e
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Showing 2 changed files with 69 additions and 35 deletions.
diff --git a/src/Controls/tests/DeviceTests/Elements/Entry/EntryTests.cs b/src/Controls/tests/DeviceTests/Elements/Entry/EntryTests.cs
@@ -1,7 +1,10 @@
 using System;
+using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Maui.Controls;
+using Microsoft.Maui.DeviceTests.Stubs;
 using Microsoft.Maui.Handlers;
+using Microsoft.Maui.Hosting;
 using Xunit;
 
 namespace Microsoft.Maui.DeviceTests
@@ -52,6 +55,67 @@ await InvokeOnMainThreadAsync(() =>
 				Assert.True(platformControl.IsReadOnly);
 			});
 		}
+
+
+		[Fact(DisplayName = "Unfocus will work when page is shown a 2nd time")]
+		public async Task UnFocusOnEntryAfterPagePop()
+		{
+			int unfocused = 0;
+			EnsureHandlerCreated(builder =>
+			{
+				builder.ConfigureMauiHandlers(handlers =>
+				{
+					handlers.AddHandler(typeof(Toolbar), typeof(ToolbarHandler));
+					handlers.AddHandler(typeof(NavigationPage), typeof(NavigationViewHandler));
+					handlers.AddHandler<Page, PageHandler>();
+					handlers.AddHandler(typeof(Window), typeof(WindowHandlerStub));
+					handlers.AddHandler(typeof(Entry), typeof(EntryHandler));
+
+				});
+			});
+			AutoResetEvent _focused = new AutoResetEvent(false);
+			AutoResetEvent _unFocused = new AutoResetEvent(false);
+			var entry = new Entry();
+			entry.Unfocused += (s, e) =>
+			{
+				if (!e.IsFocused)
+				{
+					unfocused++;
+				}
+				_unFocused.Set();
+			};
+			var navPage = new NavigationPage(new ContentPage { Content = entry });
+			var window = new Window(navPage);
+
+			await CreateHandlerAndAddToWindow<WindowHandlerStub>(window, async (handler) =>
+			{
+				await Task.Run(() =>
+				{
+					InvokeOnMainThreadAsync(() =>
+					{
+						entry.Focused += (s, e) => _focused.Set();
+						entry.Focus();
+					});
+					_focused.WaitOne();
+					_focused.Reset();
+					InvokeOnMainThreadAsync(async () =>
+					{
+						entry.Unfocus();
+						await navPage.PushAsync(new ContentPage());
+						await navPage.PopAsync();
+						entry.Focus();
+					});
+					_focused.WaitOne();
+					_unFocused.Reset();
+					InvokeOnMainThreadAsync(() =>
+					{
+						entry.Unfocus();
+					});
+					_unFocused.WaitOne();
+					Assert.True(unfocused == 2);
+				});
+			});
+		}
 #endif
 
 		[Theory(DisplayName = "CursorPosition Initializes Correctly")]

diff --git a/src/Core/src/Platform/Windows/ViewExtensions.cs b/src/Core/src/Platform/Windows/ViewExtensions.cs
@@ -19,8 +19,6 @@ namespace Microsoft.Maui.Platform
 {
 	public static partial class ViewExtensions
 	{
-		internal static Page? ContainingPage; // Cache of containing page used for unfocusing
-
 		public static void TryMoveFocus(this FrameworkElement platformView, FocusNavigationDirection direction)
 		{
 			if (platformView?.XamlRoot?.Content is UIElement elem)
@@ -361,39 +359,11 @@ internal static void UnfocusControl(Control control)
 			if (control == null || !control.IsEnabled)
 				return;
 
-			// "Unfocusing" doesn't really make sense on Windows; for accessibility reasons,
-			// something always has focus. So forcing the unfocusing of a control would normally 
-			// just move focus to the next control, or leave it on the current control if no other
-			// focus targets are available. This is what happens if you use the "disable/enable"
-			// hack. What we *can* do is set the focus to the Page which contains Control;
-			// this will cause Control to lose focus without shifting focus to, say, the next Entry 
-
-			if (ContainingPage == null)
-			{
-				// Work our way up the tree to find the containing Page
-				DependencyObject parent = control;
-
-				while (parent != null && parent is not Page)
-				{
-					parent = VisualTreeHelper.GetParent(parent);
-				}
-
-				ContainingPage = parent as Page;
-			}
-
-			if (ContainingPage != null)
-			{
-				// Cache the tabstop setting
-				var wasTabStop = ContainingPage.IsTabStop;
-
-				// Controls can only get focus if they're a tabstop
-				ContainingPage.IsTabStop = true;
-				ContainingPage.Focus(FocusState.Programmatic);
-
-				// Restore the tabstop setting; that may cause the Page to lose focus,
-				// but it won't restore the focus to Control
-				ContainingPage.IsTabStop = wasTabStop;
-			}
+			var isTabStop = control.IsTabStop;
+			control.IsTabStop = false;
+			control.IsEnabled = false;
+			control.IsEnabled = true;
+			control.IsTabStop = isTabStop;
 		}
 
 		internal static IWindow? GetHostedWindow(this IView? view)