HWND hWnd = ::FindWindow(NULL, _T("sss.txt - 记事本"));
DWORD dwTID=0;
DWORD dwPID = NULL;
dwTID = ::GetWindowThreadProcessId(hWnd, &dwPID);//获取指定窗口线程ID和进程ID
//参数1:窗口句柄HWND
//参数2:LPDWORD 保存进程ID
//返回值:线程ID
CString str;
str.Format(_T("%d"), dwPID);
AfxMessageBox(str);