feat: add demo page.

demo/Ursa.Demo/ViewModels/MainViewViewModel.cs

@@ -89,6 +89,7 @@ public partial class MainViewViewModel : ViewModelBase
             MenuKeys.MenuKeyAspectRatioLayout => new AspectRatioLayoutDemoViewModel(),
             MenuKeys.MenuKeyPathPicker => new PathPickerDemoViewModel(),
             MenuKeys.MenuKeyAnchor => new AnchorDemoViewModel(),
+            MenuKeys.MenuKeyMultiAutoCompleteBox => new MultiAutoCompleteBoxDemoViewModel(),
             _ => throw new ArgumentOutOfRangeException(nameof(s), s, null)
         };
     }

demo/Ursa.Demo/ViewModels/MenuViewModel.cs

@@ -24,6 +24,7 @@ public class MenuViewModel : ViewModelBase
                     new() { MenuHeader = "KeyGestureInput", Key = MenuKeys.MenuKeyKeyGestureInput },
                     new() { MenuHeader = "IPv4Box", Key = MenuKeys.MenuKeyIpBox },
                     new() { MenuHeader = "MultiComboBox", Key = MenuKeys.MenuKeyMultiComboBox },
+                    new() { MenuHeader = "Multi AutoCompleteBox", Key = MenuKeys.MenuKeyMultiAutoCompleteBox, Status = "New" },
                     new() { MenuHeader = "Numeric UpDown", Key = MenuKeys.MenuKeyNumericUpDown },
                     new() { MenuHeader = "NumPad", Key = MenuKeys.MenuKeyNumPad },
                     new() { MenuHeader = "PathPicker", Key = MenuKeys.MenuKeyPathPicker, Status = "New" },
@@ -158,4 +159,5 @@ public static class MenuKeys
     public const string MenuKeyAspectRatioLayout = "AspectRatioLayout";
     public const string MenuKeyPathPicker = "PathPicker";
     public const string MenuKeyAnchor = "Anchor";
+    public const string MenuKeyMultiAutoCompleteBox = "MultiAutoCompleteBox";
 }

demo/Ursa.Demo/ViewModels/MultiAutoCompleteBoxDemoViewModel.cs

@@ -0,0 +1,8 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+
+namespace Ursa.Demo.ViewModels;
+
+public class MultiAutoCompleteBoxDemoViewModel: ObservableObject
+{
+    
+}