```c++ void CMainDlg::OnLButtonDown(UINT nFlags, CPoint point) { // TODO: 在此添加消息处理程序代码和/或调用默认值 CString str; str.Format(_T("x-=%d,y=%d"),point.x,point.y); if (MK_CONTROL & nFlags) { str += _T("按下了Ctrl"); } if (MK_SHIFT & nFlags) { str += _T("按下了Shift"); } AfxMessageBox(str); CDialog::OnLButtonDown(nFlags, point); } ```