fix: Fixed the problem that the AvaloniaRider plugin on Windows cannot display the live preview for Avalonia XAML

Author: gadfly3173

src/Native/Windows.cs

@@ -73,26 +73,21 @@ public void SetupApp(AppBuilder builder)
             v.dwOSVersionInfoSize = (uint)Marshal.SizeOf<RTL_OSVERSIONINFOEX>();
             if (RtlGetVersion(ref v) == 0 && (v.dwMajorVersion < 10 || v.dwBuildNumber < 22000))
             {
-                Window.WindowStateProperty.Changed.AddClassHandler<Window>((w, e) =>
-                {
-                    if (w.WindowState != WindowState.Maximized)
-                    {
-                        var margins = new MARGINS { cxLeftWidth = 1, cxRightWidth = 1, cyTopHeight = 1, cyBottomHeight = 1 };
-                        DwmExtendFrameIntoClientArea(w.TryGetPlatformHandle().Handle, ref margins);
-                    }
-                });
-
-                Window.LoadedEvent.AddClassHandler<Window>((w, e) =>
-                {
-                    if (w.WindowState != WindowState.Maximized)
-                    {
-                        var margins = new MARGINS { cxLeftWidth = 1, cxRightWidth = 1, cyTopHeight = 1, cyBottomHeight = 1 };
-                        DwmExtendFrameIntoClientArea(w.TryGetPlatformHandle().Handle, ref margins);
-                    }
-                });
+                Window.WindowStateProperty.Changed.AddClassHandler<Window>((w, e) => ExtendWindowFrame(w));
+                Window.LoadedEvent.AddClassHandler<Window>((w, e) => ExtendWindowFrame(w));
             }
         }
 
+        private void ExtendWindowFrame(Window w)
+        {
+            var platformHandle = w.TryGetPlatformHandle();
+            if (platformHandle == null)
+                return;
+
+            var margins = new MARGINS { cxLeftWidth = 1, cxRightWidth = 1, cyTopHeight = 1, cyBottomHeight = 1 };
+            DwmExtendFrameIntoClientArea(platformHandle.Handle, ref margins);
+        }
+
         public string FindGitExecutable()
         {
             var reg = Microsoft.Win32.RegistryKey.OpenBaseKey(