优化更新代码，添加界面功能并整合

WPFluent/Extensions/NavigationServiceExtensions.cs

@@ -0,0 +1,32 @@
+
+
+
+using WPFluent.Controls;
+
+namespace WPFluent.Extensions;
+
+/// <summary>
+/// Extensions for the <see cref="INavigationService"/>.
+/// </summary>
+public static class NavigationServiceExtensions
+{
+    /// <summary>
+    /// Sets the pane display mode of the navigation service.
+    /// </summary>
+    /// <param name="navigationService">The navigation service.</param>
+    /// <param name="paneDisplayMode">The pane display mode.</param>
+    /// <returns>Same <see cref="INavigationService"/> so multiple calls can be chained.</returns>
+    public static INavigationService SetPaneDisplayMode(
+        this INavigationService navigationService,
+        NavigationViewPaneDisplayMode paneDisplayMode)
+    {
+        INavigationView? navigationControl = navigationService.GetNavigationControl();
+
+        if(navigationControl is not null)
+        {
+            navigationControl.PaneDisplayMode = paneDisplayMode;
+        }
+
+        return navigationService;
+    }
+}