优化更新代码，添加界面功能并整合

WPFluent/ContentDialogService.cs

@@ -0,0 +1,48 @@
+
+
+
+using WPFluent.Controls;
+
+using System.Windows.Controls;
+
+namespace WPFluent;
+
+/// <summary>
+/// Represents a contract with the service that creates <see cref="ContentDialog"/>.
+/// </summary>
+/// <example>
+/// <code lang="xml"> &lt;ContentPresenter x:Name="RootContentDialogPresenter" Grid.Row="0" /&gt;</code> <code
+/// lang="csharp"> IContentDialogService contentDialogService = new ContentDialogService();
+/// contentDialogService.SetContentPresenter(RootContentDialogPresenter);  await _contentDialogService.ShowAsync( new
+/// ContentDialog(){ Title = "The cake?", Content = "IS A LIE!", PrimaryButtonText = "Save", SecondaryButtonText =
+/// "Don't Save", CloseButtonText = "Cancel" } );</code>
+/// </example>
+public class ContentDialogService : IContentDialogService
+{
+    private ContentPresenter? _dialogHost;
+
+    /// <inheritdoc/>
+    public ContentPresenter? GetDialogHost() { return _dialogHost; }
+
+
+    /// <inheritdoc/>
+    public void SetDialogHost(ContentPresenter contentPresenter) { _dialogHost = contentPresenter; }
+
+    /// <inheritdoc/>
+    public Task<ContentDialogResult> ShowAsync(ContentDialog dialog, CancellationToken cancellationToken)
+    {
+        if (_dialogHost == null)
+        {
+            throw new InvalidOperationException("The DialogHost was never set.");
+        }
+
+        if (dialog.DialogHost != null && _dialogHost != dialog.DialogHost)
+        {
+            throw new InvalidOperationException("The DialogHost is not the same as the one that was previously set.");
+        }
+
+        dialog.DialogHost = _dialogHost;
+
+        return dialog.ShowAsync(cancellationToken);
+    }
+}