Fix for MenuFlyoutItem stops working after navigating away from and back to page (#25170)

* fix-21675-Updated the BindingContext of MenuBarItem after page navigation.

* fix-21675- Added UI testcase.

* fix-21675-Removed unwanted space.

* fix-21675-removed unwanted spacing.

* fix-21675-Updated testcase.

* fix-21675-Updated the BindingContext of MenuBarItem after page navigation.

* fix-21675- Added UI testcase.

* fix-21675-Removed unwanted space.

* fix-21675-removed unwanted spacing.

* fix-21675-Updated testcase.

* fix-21675-Updated testcase script.

* fix-21675-Updated testcase which only execute for the Windows and MacOS

* fix-21675-Moved testcase classes to Issue21675.

* Update src/Controls/src/Core/Page/Page.cs

* fix-21675-Added UnitTestcase and removed UI testcase.

* fix-21675- Parent of the MenuBarItems only null when the parent is MenuBar instead of page.

---------

Co-authored-by: Rui Marinho <[email protected]>

Author: BagavathiPerumal

src/Controls/src/Core/Menu/MenuBar.cs

@@ -113,7 +113,7 @@ public void RemoveAt(int index)
 			_menus.RemoveAt(index);
 			NotifyHandler(nameof(IMenuBarHandler.Remove), index, item);
 
-			if (item is Element e)
+			if (item is Element e && e.Parent == this)
 				e.Parent = null;
 		}
 

src/Controls/tests/Core.UnitTests/Menu/MenuTestBase.cs

@@ -137,14 +137,17 @@ public void ClearUpdatesParent()
 			if (typeof(TChildType) == typeof(MenuBarItem))
 			{
 				(child0.Parent as ContentPage)!.MenuBarItems.Clear();
+
+				Assert.NotNull(child0.Parent);
+				Assert.NotNull(child1.Parent);
 			}
 			else
 			{
 				menuBar.Clear();
-			}
 
-			Assert.Null(child0.Parent);
-			Assert.Null(child1.Parent);
+				Assert.Null(child0.Parent);
+				Assert.Null(child1.Parent);
+			}
 		}
 
 		[Fact]

src/Controls/tests/Core.UnitTests/MenuItemTests.cs

@@ -192,5 +192,46 @@ public void PartialHierarchyCanBeDisabled()
 			Assert.False(bottomLevelItem1.IsEnabled);
 			Assert.False(bottomLevelItem2.IsEnabled);
 		}
+
+		[Fact]
+		public async void UpdateMenuBarItemBindingContext()
+		{
+			bool fired = false;
+			var cmd = new Command(() => fired = true);
+			var bindingContext = new
+			{
+				MenuItemCommand = cmd
+			};
+
+			MenuFlyoutItem flyout;
+			MenuBarItem menuItem;
+			var mainPage = new ContentPage
+			{
+				MenuBarItems =
+				{
+					(menuItem = new MenuBarItem
+					{
+						(flyout = new MenuFlyoutItem { })
+					})
+				}
+			};
+
+			mainPage.BindingContext = bindingContext;
+			flyout.SetBinding(MenuFlyoutItem.CommandProperty, new Binding("MenuItemCommand"));
+
+			var page = new ContentPage
+			{
+				BindingContext = bindingContext
+			};
+
+			NavigationPage nav = new NavigationPage(mainPage);
+			TestWindow testWindow = new TestWindow(nav);
+			await mainPage.Navigation.PushAsync(page);
+			await page.Navigation.PopAsync();
+
+			flyout.Command.Execute(null);
+
+			Assert.True(fired);
+		}
 	}
 }