feat: add demo page.

demo/Ursa.Demo/Pages/MultiAutoCompleteBoxDemo.axaml

@@ -0,0 +1,12 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             xmlns:u="https://irihi.tech/ursa"
+             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
+             x:Class="Ursa.Demo.Pages.MultiAutoCompleteBoxDemo">
+    <StackPanel>
+        <TextBlock Text="Multi-AutoCompleteBox"/>
+        <u:MultiAutoCompleteBox />
+    </StackPanel>
+</UserControl>

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

@@ -0,0 +1,13 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+
+namespace Ursa.Demo.Pages;
+
+public partial class MultiAutoCompleteBoxDemo : UserControl
+{
+    public MultiAutoCompleteBoxDemo()
+    {
+        InitializeComponent();
+    }
+}

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
+{
+    
+}