优化更新代码，添加界面功能并整合

WPFluent/Controls/MessageBox/MessageBoxClosedEventArgs.cs

@@ -0,0 +1,13 @@
+using System.Windows;
+
+namespace WPFluent.Controls;
+
+public class MessageBoxClosedEventArgs : RoutedEventArgs
+{
+    internal MessageBoxClosedEventArgs(System.Windows.MessageBoxResult result)
+    {
+        Result = result;
+    }
+
+    public System.Windows.MessageBoxResult Result { get; }
+}