WPF获取顶部的窗口

       
　　　　　//从Handle中获取Window对象
        private static Window GetWindowFromHwnd(IntPtr hwnd)
        {
            var fromHwnd = HwndSource.FromHwnd(hwnd);
            if (fromHwnd != null) return (Window)fromHwnd.RootVisual;
            return null;
        }
 　　　　[DllImport("user32.dll")]
        static extern IntPtr GetActiveWindow();

        /////调用GetForegroundWindow然后调用GetWindowFromHwnd

        /// <summary>
        /// 获取当前顶级窗体，若获取失败则返回主窗体
        /// </summary>
        public static Window GetTopWindow()
        {
            var hwnd = GetActiveWindow();
            if (hwnd == IntPtr.Zero)
                return Application.Current.MainWindow;
                

            return GetWindowFromHwnd(hwnd);
        }