用pid 取主窗口 hwnd

HWND GetHwndByPid(DWORD dwProcessID)
{
    HWND h = GetTopWindow();
    HWND retHwnd = NULL;
    while ( h )
    {
        DWORD pid = ;
        DWORD dwTheardId = GetWindowThreadProcessId( h,&pid);
        if (dwTheardId != )
        {
            if ( pid == dwProcessID && GetParent(h)==NULL && ::IsWindowVisible(h))
            {
                retHwnd = h;    //会有多个相等值
                //    /*
                char buf[MAX_PATH] = {};
                sprintf(buf,"%0x",h);
                MessageBox(NULL,buf,"提示",MB_OK);
                //    */
            }
        }
        h  = GetNextWindow(h,GW_HWNDNEXT);
    }
    return retHwnd;
}

网上的基本是全身错误的那个版本。