Add HandlerProperties.DisconnectPolicy for controlling when DisconnectHandler is called

src/Controls/src/Core/Compatibility/Handlers/NavigationPage/iOS/NavigationRenderer.cs

@@ -890,7 +890,7 @@ async Task UpdateFormsInnerNavigation(Page pageBeingRemoved)
 				await (NavPage as INavigationPageController)?.RemoveAsyncInner(pageBeingRemoved, false, true);
 				if (_uiRequestedPop)
 				{
-					NavPage?.SendNavigatedFromHandler(pageBeingRemoved);
+					NavPage?.SendNavigatedFromHandler(pageBeingRemoved, NavigationType.Pop);
 				}
 			}
 
@@ -1097,8 +1097,8 @@ public override void DidShowViewController(UINavigationController navigationCont
 
 					if (r.Element is NavigationPage np && !_finishedWithInitialNavigation)
 					{
-						_finishedWithInitialNavigation = true;
-						np.SendNavigatedFromHandler(null);
+						_finishedWithInitialNavigation = true;						
+						np.SendNavigatedFromHandler(null, NavigationType.Push);
 					}
 
 					if (WaitingForNavigationToFinish)
@@ -1969,7 +1969,7 @@ protected override void Dispose(bool disposing)
 				if (disposing)
 				{
 
-					if (_child != null)
+					if (_child?.IsConnected() == true)
 					{
 						_child.PlatformView.RemoveFromSuperview();
 						_child.DisconnectHandler();

src/Controls/src/Core/Compatibility/Handlers/Shell/Android/ShellToolbarTracker.cs

@@ -68,19 +68,25 @@ void IFlyoutBehaviorObserver.OnFlyoutBehaviorChanged(FlyoutBehavior behavior)
 		DrawerArrowDrawable _drawerArrowDrawable;
 		FlyoutIconDrawerDrawable _flyoutIconDrawerDrawable;
 		IToolbar _toolbar;
-		protected IMauiContext MauiContext => ShellContext.Shell.Handler.MauiContext;
+		protected IMauiContext MauiContext => _shell.Handler.MauiContext;
+
+		Toolbar _shellRootToolBar;
+		Shell _shell;
 
 		public ShellToolbarTracker(IShellContext shellContext, AToolbar toolbar, DrawerLayout drawerLayout)
 		{
 			ShellContext = shellContext ?? throw new ArgumentNullException(nameof(shellContext));
+			_shell = shellContext.Shell;
+
 			_platformToolbar = toolbar ?? throw new ArgumentNullException(nameof(toolbar));
 			_drawerLayout = drawerLayout ?? throw new ArgumentNullException(nameof(drawerLayout));
 			_appBar = _platformToolbar.Parent.GetParentOfType<AppBarLayout>();
 
 			_globalLayoutListener = new GenericGlobalLayoutListener((_, _) => UpdateNavBarHasShadow(Page), _appBar);
 			_platformToolbar.SetNavigationOnClickListener(this);
 			((IShellController)ShellContext.Shell).AddFlyoutBehaviorObserver(this);
-			ShellContext.Shell.Toolbar.PropertyChanged += OnToolbarPropertyChanged;
+			_shellRootToolBar = _shell.Toolbar;
+			_shellRootToolBar.PropertyChanged += OnToolbarPropertyChanged;
 			ShellContext.Shell.Navigated += OnShellNavigated;
 			ShellContext.Shell.PropertyChanged += HandleShellPropertyChanged;
 		}
@@ -162,7 +168,7 @@ void AView.IOnClickListener.OnClick(AView v)
 				else if (CanNavigateBack)
 					OnNavigateBack();
 				else
-					ShellContext.Shell.FlyoutIsPresented = !ShellContext.Shell.FlyoutIsPresented;
+					_shell.FlyoutIsPresented = !_shell.FlyoutIsPresented;
 			}
 		}
 
@@ -181,9 +187,9 @@ protected override void Dispose(bool disposing)
 					_backButtonBehavior.PropertyChanged -= OnBackButtonBehaviorChanged;
 
 				((IShellController)ShellContext.Shell)?.RemoveFlyoutBehaviorObserver(this);
-				ShellContext.Shell.Toolbar.PropertyChanged -= OnToolbarPropertyChanged;
-				ShellContext.Shell.Navigated -= OnShellNavigated;
-				ShellContext.Shell.PropertyChanged -= HandleShellPropertyChanged;
+				_shellRootToolBar.PropertyChanged -= OnToolbarPropertyChanged;
+				_shell.Navigated -= OnShellNavigated;
+				_shell.PropertyChanged -= HandleShellPropertyChanged;
 				UpdateTitleView(ShellContext.AndroidContext, _platformToolbar, null);
 
 				if (_searchView != null)
@@ -212,6 +218,7 @@ protected override void Dispose(bool disposing)
 			_platformToolbar = null;
 			_appBar = null;
 			_drawerLayout = null;
+			_shell = null;
 
 			base.Dispose(disposing);
 		}
@@ -261,8 +268,8 @@ protected virtual void OnPageChanged(Page oldPage, Page newPage)
 				UpdateNavBarHasShadow(newPage);
 				UpdateTitleView();
 
-				if (ShellContext.Shell.Toolbar is ShellToolbar shellToolbar &&
-					newPage == ShellContext.Shell.GetCurrentShellPage())
+				if (_shell.Toolbar is ShellToolbar shellToolbar &&
+					newPage == _shell.GetCurrentShellPage())
 				{
 					shellToolbar.ApplyChanges();
 				}
@@ -274,8 +281,8 @@ void OnShellNavigated(object sender, ShellNavigatedEventArgs e)
 			if (_disposed || Page == null)
 				return;
 
-			if (ShellContext?.Shell?.Toolbar is ShellToolbar &&
-				Page == ShellContext?.Shell?.GetCurrentShellPage())
+			if (_shell?.Toolbar is ShellToolbar &&
+				Page == _shell?.GetCurrentShellPage())
 			{
 				UpdateLeftBarButtonItem();
 				UpdateTitleView();
@@ -402,7 +409,7 @@ protected virtual async void UpdateLeftBarButtonItem(Context context, AToolbar t
 			var backButtonHandler = Shell.GetBackButtonBehavior(page);
 			var text = backButtonHandler.GetPropertyIfSet(BackButtonBehavior.TextOverrideProperty, String.Empty);
 			var command = backButtonHandler.GetPropertyIfSet<ICommand>(BackButtonBehavior.CommandProperty, null);
-			bool isEnabled = ShellContext.Shell.Toolbar.BackButtonEnabled;
+			bool isEnabled = _shell.Toolbar.BackButtonEnabled;
 			var image = GetFlyoutIcon(backButtonHandler, page);
 			var backButtonVisible = _toolbar.BackButtonVisible;
 
@@ -496,7 +503,7 @@ protected virtual async void UpdateLeftBarButtonItem(Context context, AToolbar t
 
 
 			//this needs to be set after SyncState
-			UpdateToolbarIconAccessibilityText(toolbar, ShellContext.Shell);
+			UpdateToolbarIconAccessibilityText(toolbar, _shell);
 			_toolbar?.Handler?.UpdateValue(nameof(Toolbar.IconColor));
 		}
 
@@ -604,10 +611,10 @@ void UpdateNavBarHasShadow(Page page)
 
 		void OnToolbarPropertyChanged(object sender, PropertyChangedEventArgs e)
 		{
-			if (_toolbar != null && ShellContext?.Shell?.GetCurrentShellPage() == Page)
+			if (_toolbar != null && _shell?.GetCurrentShellPage() == Page)
 			{
 				ApplyToolbarChanges((Toolbar)sender, (Toolbar)_toolbar);
-				UpdateToolbarIconAccessibilityText(_platformToolbar, ShellContext.Shell);
+				UpdateToolbarIconAccessibilityText(_platformToolbar, _shell);
 			}
 		}
 
@@ -617,7 +624,7 @@ protected virtual void UpdatePageTitle(AToolbar toolbar, Page page)
 
 		protected virtual void UpdateTitleView(Context context, AToolbar toolbar, View titleView)
 		{
-			if (_toolbar != null && ShellContext?.Shell?.GetCurrentShellPage() == Page)
+			if (_toolbar != null && _shell?.GetCurrentShellPage() == Page)
 				_toolbar.Handler?.UpdateValue(nameof(Toolbar.TitleView));
 		}
 

src/Controls/src/Core/Element/Element.cs

@@ -46,7 +46,7 @@ namespace Microsoft.Maui.Controls
 	///			</item>
 	///		</list>
 	///</remarks>
-	public abstract partial class Element : BindableObject, IElementDefinition, INameScope, IElementController, IVisualTreeElement, Maui.IElement, IEffectControlProvider, IToolTipElement, IContextFlyoutElement, IControlsElement
+	public abstract partial class Element : BindableObject, IElementDefinition, INameScope, IElementController, IVisualTreeElement, Maui.IElement, IEffectControlProvider, IToolTipElement, IContextFlyoutElement, IControlsElement, IHandlerDisconnectPolicies
 	{
 		internal static readonly ReadOnlyCollection<Element> EmptyChildren = new ReadOnlyCollection<Element>(Array.Empty<Element>());
 
@@ -1026,6 +1026,12 @@ void IEffectControlProvider.RegisterEffect(Effect effect)
 		/// <inheritdoc/>
 		IFlyout IContextFlyoutElement.ContextFlyout => FlyoutBase.GetContextFlyout(this);
 
+		HandlerDisconnectPolicy IHandlerDisconnectPolicies.DisconnectPolicy 
+		{ 
+			get => HandlerProperties.GetDisconnectPolicy(this);
+			set => HandlerProperties.SetDisconnectPolicy(this, value);
+		}
+
 		class TemporaryWrapper : IList<Element>
 		{
 			IReadOnlyList<Element> _inner;

src/Controls/src/Core/FlyoutPage/FlyoutPage.cs

@@ -66,7 +66,7 @@ public Page Detail
 					_detail?.SendAppearing();
 				}
 
-				previousDetail?.SendNavigatedFrom(new NavigatedFromEventArgs(_detail));
+				previousDetail?.SendNavigatedFrom(new NavigatedFromEventArgs(_detail, NavigationType.PageSwap));
 				_detail?.SendNavigatedTo(new NavigatedToEventArgs(previousDetail));
 			}
 		}
@@ -121,7 +121,7 @@ public Page Flyout
 					_flyout?.SendAppearing();
 				}
 
-				previousFlyout?.SendNavigatedFrom(new NavigatedFromEventArgs(_flyout));
+				previousFlyout?.SendNavigatedFrom(new NavigatedFromEventArgs(_flyout, NavigationType.PageSwap));
 				_flyout?.SendNavigatedTo(new NavigatedToEventArgs(previousFlyout));
 			}
 		}

src/Controls/src/Core/Handlers/HandlerProperties.cs

@@ -0,0 +1,23 @@
+using Microsoft.Maui;
+
+namespace Microsoft.Maui.Controls
+{
+	public static class HandlerProperties
+	{
+        public static readonly BindableProperty DisconnectPolicyProperty = BindableProperty.CreateAttached(
+            "DisconnectPolicy",
+            typeof(HandlerDisconnectPolicy),
+            typeof(HandlerProperties),
+            HandlerDisconnectPolicy.Automatic);
+
+        public static void SetDisconnectPolicy(BindableObject target, HandlerDisconnectPolicy value)
+        {
+            target.SetValue(DisconnectPolicyProperty, value);
+        }
+
+        public static HandlerDisconnectPolicy GetDisconnectPolicy(BindableObject target)
+        {
+            return (HandlerDisconnectPolicy)target.GetValue(DisconnectPolicyProperty);
+        }
+    }
+}

src/Controls/src/Core/Handlers/Items/CarouselViewHandler.Windows.cs

@@ -50,11 +50,8 @@ protected override void DisconnectHandler(ListViewBase platformView)
 			if (ItemsView != null)
 				ItemsView.Scrolled -= CarouselScrolled;
 
-			if (ListViewBase != null)
-			{
-				ListViewBase.SizeChanged -= OnListViewSizeChanged;
-				_proxy.Unsubscribe();
-			}
+			platformView.SizeChanged -= OnListViewSizeChanged;
+			_proxy.Unsubscribe();
 
 			if (_scrollViewer != null)
 			{

src/Controls/src/Core/Handlers/Shell/Windows/ShellView.cs

@@ -274,6 +274,6 @@ ShellItemHandler CreateShellItemView()
 		}
 
 		void TabSelectionChanged(NavigationView sender, NavigationViewSelectionChangedEventArgs args) =>
-			Element.Handler.UpdateValue(nameof(Shell.CurrentItem));
+			Element?.Handler?.UpdateValue(nameof(Shell.CurrentItem));
 	}
 }

src/Controls/src/Core/MultiPage.cs

@@ -97,7 +97,7 @@ public T CurrentPage
 				if (HasAppeared)
 					_current?.SendAppearing();
 
-				previousPage?.SendNavigatedFrom(new NavigatedFromEventArgs(_current));
+				previousPage?.SendNavigatedFrom(new NavigatedFromEventArgs(_current, NavigationType.PageSwap));
 				_current?.SendNavigatedTo(new NavigatedToEventArgs(previousPage));
 			}
 		}

src/Controls/src/Core/NavigationPage/NavigationPage.Legacy.cs

@@ -27,7 +27,7 @@ async Task<Page> PopAsyncInner(
 			var previousPage = CurrentPage;
 			SendNavigating();
 			var removedPage = await RemoveAsyncInner(page, animated, fast);
-			SendNavigated(previousPage);
+			SendNavigated(previousPage, NavigationType.Pop);
 			return removedPage;
 		}
 
@@ -174,7 +174,7 @@ async Task PopToRootAsyncInner(bool animated)
 			}
 
 			PoppedToRoot?.Invoke(this, new PoppedToRootEventArgs(RootPage, childrenToRemove.OfType<Page>().ToList()));
-			SendNavigated(previousPage);
+			SendNavigated(previousPage, NavigationType.PopToRoot);
 		}
 
 		async Task PushAsyncInner(Page page, bool animated)
@@ -200,7 +200,7 @@ async Task PushAsyncInner(Page page, bool animated)
 					await args.Task;
 			}
 
-			SendNavigated(previousPage);
+			SendNavigated(previousPage, NavigationType.Push);
 			Pushed?.Invoke(this, args);
 		}
 
@@ -209,12 +209,12 @@ async Task PushAsyncInner(Page page, bool animated)
 		// there are scenarios where the legacy handler needs to alert the xplat
 		// code of when a navigation has occurred.
 		// For example, initial load and when the user taps the back button
-		internal void SendNavigatedFromHandler(Page previousPage)
+		internal void SendNavigatedFromHandler(Page previousPage, NavigationType navigationType)
 		{
 			if (CurrentPage.HasNavigatedTo)
 				return;
 
-			SendNavigated(previousPage);
+			SendNavigated(previousPage, navigationType);
 		}
 #endif
 

src/Controls/src/Core/NavigationPage/NavigationPage.cs

@@ -374,9 +374,9 @@ protected override bool OnBackButtonPressed()
 			return base.OnBackButtonPressed();
 		}
 
-		void SendNavigated(Page previousPage)
+		void SendNavigated(Page previousPage, NavigationType navigationType)
 		{
-			previousPage?.SendNavigatedFrom(new NavigatedFromEventArgs(CurrentPage));
+			previousPage?.SendNavigatedFrom(new NavigatedFromEventArgs(CurrentPage, navigationType));
 			CurrentPage.SendNavigatedTo(new NavigatedToEventArgs(previousPage));
 		}
 
@@ -699,7 +699,8 @@ private protected override void OnHandlerChangedCore()
 				},
 				() =>
 				{
-					SendNavigated(null);
+					// TODO this is the wrong navigation type
+					SendNavigated(null, NavigationType.Initialize);
 				})
 				.FireAndForget(Handler);
 			}
@@ -797,7 +798,7 @@ await Owner.SendHandlerUpdateAsync(animated,
 					},
 					() =>
 					{
-						Owner.SendNavigated(currentPage);
+						Owner.SendNavigated(currentPage, NavigationType.Pop);
 						Owner?.Popped?.Invoke(Owner, new NavigationEventArgs(currentPage));
 					});
 
@@ -834,7 +835,7 @@ protected override Task OnPopToRootAsync(bool animated)
 					},
 					() =>
 					{
-						Owner.SendNavigated(previousPage);
+						Owner.SendNavigated(previousPage, NavigationType.PopToRoot);
 						Owner?.PoppedToRoot?.Invoke(Owner, new PoppedToRootEventArgs(newPage, pagesToRemove));
 					});
 			}
@@ -859,7 +860,7 @@ protected override Task OnPushAsync(Page root, bool animated)
 					},
 					() =>
 					{
-						Owner.SendNavigated(previousPage);
+						Owner.SendNavigated(previousPage, NavigationType.Push);
 						Owner?.Pushed?.Invoke(Owner, new NavigationEventArgs(root));
 					});
 			}

src/Controls/src/Core/Page/NavigatedFromEventArgs.cs

@@ -1,15 +1,30 @@
 #nullable disable
 using System;
+using Microsoft.Maui.Controls.Internals;
 
 namespace Microsoft.Maui.Controls
 {
+	internal enum NavigationType
+	{
+		Push,
+		Pop,
+		PopToRoot,
+		Insert,
+		Remove,
+		PageSwap,
+		Initialize
+	}
+
 	public sealed class NavigatedFromEventArgs : EventArgs
 	{
-		internal NavigatedFromEventArgs(Page destinationPage)
+		internal NavigationType NavigationType { get; }
+
+		internal Page DestinationPage { get; }
+
+		internal NavigatedFromEventArgs(Page destinationPage, NavigationType navigationType)
 		{
 			DestinationPage = destinationPage;
+			NavigationType = navigationType;
 		}
-
-		internal Page DestinationPage { get; }
 	}
 }