优化更新代码，添加界面功能并整合

WPFluent/Extensions/UiElementExtensions.cs

@@ -0,0 +1,37 @@
+
+
+
+namespace WPFluent.Extensions;
+
+internal static class UiElementExtensions
+{
+    private static int Get_X_LParam(IntPtr lParam) { return (short)(lParam.ToInt32() & 0xFFFF); }
+
+    private static int Get_Y_LParam(IntPtr lParam) { return (short)(lParam.ToInt32() >> 16); }
+
+    /// <summary>
+    /// Do not call it outside of NCHITTEST, NCLBUTTONUP, NCLBUTTONDOWN messages!
+    /// </summary>
+    /// <returns><see langword="true"/> if mouse is over the element. <see langword="false"/> otherwise.</returns>
+    public static bool IsMouseOverElement(this UIElement element, IntPtr lParam)
+    {
+        // This method will be invoked very often and must be as simple as possible.
+        if(lParam == IntPtr.Zero)
+        {
+            return false;
+        }
+
+        try
+        {
+            var mousePosScreen = new Point(Get_X_LParam(lParam), Get_Y_LParam(lParam));
+            var bounds = new Rect(default, element.RenderSize);
+
+            Point mousePosRelative = element.PointFromScreen(mousePosScreen);
+
+            return bounds.Contains(mousePosRelative);
+        } catch
+        {
+            return false;
+        }
+    }
+}