取消用鼠标拖动或者用键盘在编辑框中选择的文本内容

// 0x0118这个消息是MS未文档化的消息WM_SYSTIMER (caret blink) 

BOOL CXXDlg::PreTranslateMessage(MSG* pMsg) 
{
	// TODO: Add your specialized code here and/or call the base class
	CEdit* pEdit = (CEdit*)GetDlgItem(IDC_EDIT1);
	ASSERT(pEdit);
	if((0x0118 == pMsg->message) && (pMsg->hwnd == pEdit->GetSafeHwnd()))
	{
		int start = 0;
		int end = 0;
		pEdit->GetSel(start, end);
		if(start != end)
		{
			CPoint pt;
			GetCursorPos(&pt);
			pEdit->ScreenToClient(&pt);
			int nSel = LOWORD(pEdit->CharFromPos(pt));
			pEdit->SetSel(nSel, nSel);
		}
	}
	return CDialog::PreTranslateMessage(pMsg);
}