HWND hwnd=NULL;

int iRet;

iRet=MessageBox(hwnd,"是否真的要停止？","警告",MB_YESNOMB_ICONQUESTIONMB_SYSTEMMODAL);
if (iRet==IDYES)
{
SetTagBit("MC_ON",0);
iRet=MessageBox(NULL,"你停止了传输 " , "信息",MB_OKMB_ICONSTOPMB_SETFOREGROUNDMB_SYSTEMMODAL);

}
else
{
iRet=MessageBox(NULL,"没有 " , "Error",MB_OKMB_ICONSTOPMB_SETFOREGROUNDMB_SYSTEMMODAL);
}