fix: remove Manager OnDetachedFromVisualTree.

demo/Ursa.Demo/Pages/NotificationDemo.axaml.cs

@@ -1,5 +1,7 @@
 using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Controls.Primitives;
+using Avalonia.VisualTree;
 using Ursa.Controls;
 using Ursa.Demo.ViewModels;
 
@@ -8,6 +10,7 @@ namespace Ursa.Demo.Pages;
 public partial class NotificationDemo : UserControl
 {
     private NotificationDemoViewModel _viewModel;
+    private TopLevel? _topLevel;
 
     public NotificationDemo()
     {
@@ -19,7 +22,17 @@ public partial class NotificationDemo : UserControl
     protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
     {
         base.OnAttachedToVisualTree(e);
-        var topLevel = TopLevel.GetTopLevel(this);
+        _topLevel = TopLevel.GetTopLevel(this);
-        _viewModel.NotificationManager = new WindowNotificationManager(topLevel) { MaxItems = 3 };
+        _viewModel.NotificationManager = new WindowNotificationManager(_topLevel) { MaxItems = 3 };
+    }
+
+    protected override void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
+    {
+        base.OnDetachedFromVisualTree(e);
+        var adorner = _topLevel.FindDescendantOfType<VisualLayerManager>()?.AdornerLayer;
+        if (adorner is not null && _viewModel.NotificationManager is not null)
+        {
+            adorner.Children.Remove(_viewModel.NotificationManager);
+        }
     }
 }

demo/Ursa.Demo/Pages/ToastDemo.axaml.cs

@@ -1,5 +1,7 @@
 using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Controls.Primitives;
+using Avalonia.VisualTree;
 using Ursa.Controls;
 using Ursa.Demo.ViewModels;
 
@@ -8,6 +10,7 @@ namespace Ursa.Demo.Pages;
 public partial class ToastDemo : UserControl
 {
     private ToastDemoViewModel _viewModel;
+    private TopLevel? _topLevel;
 
     public ToastDemo()
     {
@@ -19,7 +22,17 @@ public partial class ToastDemo : UserControl
     protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
     {
         base.OnAttachedToVisualTree(e);
-        var topLevel = TopLevel.GetTopLevel(this);
+        _topLevel = TopLevel.GetTopLevel(this);
-        _viewModel.ToastManager = new WindowToastManager(topLevel) { MaxItems = 3 };
+        _viewModel.ToastManager = new WindowToastManager(_topLevel) { MaxItems = 3 };
+    }
+
+    protected override void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
+    {
+        base.OnDetachedFromVisualTree(e);
+        var adorner = _topLevel.FindDescendantOfType<VisualLayerManager>()?.AdornerLayer;
+        if (adorner is not null && _viewModel.ToastManager is not null)
+        {
+            adorner.Children.Remove(_viewModel.ToastManager);
+        }
     }
 }

demo/Ursa.Demo/ViewModels/MenuViewModel.cs

@@ -37,7 +37,7 @@ public class MenuViewModel: ViewModelBase
             new() { MenuHeader = "Message Box", Key = MenuKeys.MenuKeyMessageBox },
             new() { MenuHeader = "MultiComboBox", Key = MenuKeys.MenuKeyMultiComboBox, Status = "Updated" },
             new() { MenuHeader = "Nav Menu", Key = MenuKeys.MenuKeyNavMenu },
-            new() { MenuHeader = "Notification", Key = MenuKeys.MenuKeyNotification },
+            new() { MenuHeader = "Notification", Key = MenuKeys.MenuKeyNotification, Status = "New"},
             new() { MenuHeader = "Number Displayer", Key = MenuKeys.MenuKeyNumberDisplayer, Status = "New" }, 
             new() { MenuHeader = "Numeric UpDown", Key = MenuKeys.MenuKeyNumericUpDown },
             new() { MenuHeader = "NumPad", Key = MenuKeys.MenuKeyNumPad },
@@ -54,7 +54,7 @@ public class MenuViewModel: ViewModelBase
             new() { MenuHeader = "Timeline", Key = MenuKeys.MenuKeyTimeline },
             new() { MenuHeader = "TreeComboBox", Key = MenuKeys.MenuKeyTreeComboBox },
             new() { MenuHeader = "TwoTonePathIcon", Key = MenuKeys.MenuKeyTwoTonePathIcon},
-            new() { MenuHeader = "Toast", Key = MenuKeys.MenuKeyToast },
+            new() { MenuHeader = "Toast", Key = MenuKeys.MenuKeyToast, Status = "New"},
             new() { MenuHeader = "ToolBar", Key = MenuKeys.MenuKeyToolBar },
             new() { MenuHeader = "Time Box", Key = MenuKeys.MenuKeyTimeBox },
         };

src/Ursa/Controls/NotificationShared/MessageCard.cs

@@ -196,19 +196,19 @@ public abstract class MessageCard : ContentControl
     {
         switch (NotificationType)
         {
-            case Avalonia.Controls.Notifications.NotificationType.Error:
+            case NotificationType.Error:
                 PseudoClasses.Add(PC_Error);
                 break;
 
-            case Avalonia.Controls.Notifications.NotificationType.Information:
+            case NotificationType.Information:
                 PseudoClasses.Add(PC_Information);
                 break;
 
-            case Avalonia.Controls.Notifications.NotificationType.Success:
+            case NotificationType.Success:
                 PseudoClasses.Add(PC_Success);
                 break;
 
-            case Avalonia.Controls.Notifications.NotificationType.Warning:
+            case NotificationType.Warning:
                 PseudoClasses.Add(PC_Warning);
                 break;
         }