private const int SC_SCREENSAVE = 0xF140;

         private const int WM_QUERYENDSESSION = 0x0011;

         private bool IsScreenSave = false;

         private bool IsWindowStopClosing = false;

    // 获得窗口句柄

                 IntPtr hwnd = new WindowInteropHelper(this).Handle;

                 // 在Win32窗口中显示WPF的内容

                 HwndSource src = HwndSource.FromHwnd(hwnd);

                 //接收窗口消息的处理程序实现（基于 System.Windows.Interop.HwndSourceHook 委托）

                 src.AddHook(new HwndSourceHook(WndProc));

     /// <summary>

         /// 重新WndProc

         /// </summary>

         /// <param name="hwnd">窗口句柄</param>

         /// <param name="msg">消息ID</param>

         /// <param name="wParam">消息的 wParam 值</param>

         /// <param name="lParam">消息的 lParam 值</param>

         /// <param name="handled">指示该消息是否已处理的值。如果该消息已处理，请将值设置为 true；否则请将其设置为 false</param>

         /// <returns></returns>

         private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)

         {

             if (msg == WM_QUERYENDSESSION)

             {

                 using (var wcf = new KeFuServicesClient())

                 {

                     wcf.UpdateUserState(MainPanelWindow.ClientServiceID, UserStates.UnLine);

                 }

             }

             return IntPtr.Zero;

         }