// 对话框屏幕居中
  ShowWindow(SW_NORMAL);
  CRect rtDesk;
  CRect rtDlg;
  ::GetWindowRect(::GetDesktopWindow(), &rtDesk);
  GetWindowRect(&rtDlg);
  int iXpos = rtDesk.Width() / 2 - rtDlg.Width() / 2;
  int iYpos = rtDesk.Height() / 2 - rtDlg.Height() / 2;
  SetWindowPos(NULL, iXpos, iYpos, 0, 0, SWP_NOOWNERZORDER|SWP_NOSIZE|SWP_NOZORDER);