feat: add mvvm demo.

demo/Ursa.Demo/App.axaml.cs

@@ -18,7 +18,10 @@ public partial class App : Application
     {
         if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
         {
-            desktop.MainWindow = new MainSplashWindow();
+            desktop.MainWindow = new MvvmSplashWindow()
+            {
+                DataContext = new SplashViewModel()
+            };
         }
         else if (ApplicationLifetime is ISingleViewApplicationLifetime singleView)
         {

demo/Ursa.Demo/ViewModels/SplashViewModel.cs

@@ -0,0 +1,38 @@
+using System;
+using Avalonia.Threading;
+using CommunityToolkit.Mvvm.ComponentModel;
+using Irihi.Avalonia.Shared.Contracts;
+
+namespace Ursa.Demo.ViewModels;
+
+public partial class SplashViewModel: ObservableObject, IDialogContext
+{
+    [ObservableProperty] private double _progress;
+    private Random _r = new();
+
+    public SplashViewModel()
+    {
+        DispatcherTimer.Run(OnUpdate, TimeSpan.FromMilliseconds(200), DispatcherPriority.Default);
+    }
+
+    private bool OnUpdate()
+    {
+        Progress += 10 * _r.NextDouble();
+        if (Progress <= 100)
+        {
+            return true;
+        }
+        else
+        {
+            RequestClose?.Invoke(this, null);
+            return false;
+        }
+    }
+    
+    public void Close()
+    {
+        RequestClose?.Invoke(this, null);
+    }
+
+    public event EventHandler<object?>? RequestClose;
+}

demo/Ursa.Demo/Views/MvvmSplashWindow.axaml

@@ -0,0 +1,48 @@
+<u:SplashWindow 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"
+        xmlns:viewModels="clr-namespace:Ursa.Demo.ViewModels"
+        xmlns:iri="https://irihi.tech/shared"
+        mc:Ignorable="d" 
+        Width="400" Height="400"
+        CountDown="{x:Null}"
+        x:DataType="viewModels:SplashViewModel"
+        x:Class="Ursa.Demo.Views.MvvmSplashWindow"
+        Title="MvvmSplashWindow">
+        <Grid
+                HorizontalAlignment="Center"
+                VerticalAlignment="Center"
+                ColumnDefinitions="Auto, Auto"
+                RowDefinitions="Auto, Auto, Auto">
+                <iri:IrihiLogo
+                        Grid.Row="0"
+                        Grid.Column="0"
+                        Width="64"
+                        Margin="0,0,16,0"
+                        Fill="{DynamicResource SemiGrey5}" />
+                <StackPanel Grid.Row="0" Grid.Column="1">
+                        <TextBlock
+                                Classes="H2"
+                                Text="铱泓科技"
+                                Theme="{DynamicResource TitleTextBlock}" />
+                        <TextBlock FontWeight="Bold" Text="IRIHI Technology" />
+                </StackPanel>
+                <ProgressBar Grid.Row="1" Grid.ColumnSpan="2" Value="{Binding Progress}" Margin="0 16 0 0"/>
+                <StackPanel
+                        Grid.Row="2"
+                        Grid.Column="0"
+                        Grid.ColumnSpan="2">
+                        <TextBlock
+                                Margin="0,12,0,0"
+                                HorizontalAlignment="Center"
+                                FontSize="14"
+                                Text="聚焦生产力的美学进化" />
+                        <TextBlock
+                                HorizontalAlignment="Center"
+                                FontSize="14"
+                                Text="Aesthetic Evolution of Productivity" />
+                </StackPanel>
+        </Grid>
+</u:SplashWindow>

demo/Ursa.Demo/Views/MvvmSplashWindow.axaml.cs

@@ -0,0 +1,24 @@
+using System.Threading.Tasks;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+using Ursa.Controls;
+using Ursa.Demo.ViewModels;
+
+namespace Ursa.Demo.Views;
+
+public partial class MvvmSplashWindow : SplashWindow
+{
+    public MvvmSplashWindow()
+    {
+        InitializeComponent();
+    }
+
+    protected override async Task<Window> CreateNextWindow()
+    {
+        return new MainWindow()
+        {
+            DataContext = new MainViewViewModel()
+        };
+    }
+}

src/Ursa/Windows/SplashWindow.cs

@@ -3,6 +3,7 @@ using Avalonia.Controls;
 using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Interactivity;
 using Avalonia.Threading;
+using Irihi.Avalonia.Shared.Contracts;
 
 namespace Ursa.Controls;
 
@@ -19,6 +20,24 @@ public abstract class SplashWindow: Window
         set => SetValue(CountDownProperty, value);
     }
     
+    static SplashWindow()
+    {
+        DataContextProperty.Changed.AddClassHandler<SplashWindow, object?>((window, e) =>
+            window.OnDataContextChange(e));
+    }
+    
+    private void OnDataContextChange(AvaloniaPropertyChangedEventArgs<object?> args)
+    {
+        if (args.OldValue.Value is IDialogContext oldContext) oldContext.RequestClose -= OnContextRequestClose;
+
+        if (args.NewValue.Value is IDialogContext newContext) newContext.RequestClose += OnContextRequestClose;
+    }
+    
+    private void OnContextRequestClose(object? sender, object? args)
+    {
+        Close(args);
+    }
+
     protected override void OnLoaded(RoutedEventArgs e)
     {
         base.OnLoaded(e);
@@ -49,6 +68,11 @@ public abstract class SplashWindow: Window
                 }
                 nextWindow.Show();
                 Close();
+                if (DataContext is IDialogContext idc)
+                {
+                    idc.Close();
+                    idc.RequestClose -= OnContextRequestClose;
+                }
                 return;
             }
         }