BOOL CWelcomeDlg::PreTranslateMessage(MSG* pMsg) //Called to filter messages before they are dispatched{    // TODO: Add your specialized code here and/or call the base class    if(pMsg->message == WM_KEYDOWN && pMsg->wParam == 27)    {        CString s;        s.Format("The wParam= %d The message = %d", pMsg->wParam, pMsg->message);        MessageBox(s);        return NULL;    }    return CDialog::PreTranslateMessage(pMsg);} 在消息调用之前的函数