优化更新代码，添加界面功能并整合

WPFluent/Controls/NavigationView/NavigationViewPageProviderExtensions.cs

@@ -0,0 +1,34 @@
+
+
+
+namespace WPFluent.Abstractions;
+
+/// <summary>
+/// Provides extension methods for the INavigationViewPageProvider interface.
+/// </summary>
+public static class NavigationViewPageProviderExtensions
+{
+    /// <summary>
+    /// Retrieves a page of the specified type from the page service.
+    /// </summary>
+    /// <typeparam name="TPage">The type of the page to retrieve.</typeparam>
+    /// <param name="navigationViewPageProvider">The page service instance.</param>
+    /// <returns>An instance of the specified page type, or null if the page is not found.</returns>
+    public static TPage? GetPage<TPage>(this INavigationViewPageProvider navigationViewPageProvider) where TPage : class
+    { return navigationViewPageProvider.GetPage(typeof(TPage)) as TPage; }
+
+    /// <summary>
+    /// Retrieves a page of the specified type from the page service. Throws a NavigationException if the page is not
+    /// found.
+    /// </summary>
+    /// <typeparam name="TPage">The type of the page to retrieve.</typeparam>
+    /// <param name="navigationViewPageProvider">The page service instance.</param>
+    /// <returns>An instance of the specified page type.</returns>
+    /// <exception cref="NavigationException">Thrown when the specified page type is not found.</exception>
+    public static TPage GetRequiredPage<TPage>(this INavigationViewPageProvider navigationViewPageProvider)
+        where TPage : class
+    {
+        return navigationViewPageProvider.GetPage(typeof(TPage)) as TPage ??
+            throw new NavigationException($"{typeof(TPage)} page not found.");
+    }
+}