CButtonMenu

void CMenuBtnDlg::OnMenubutton()
{
    CMenu menu, *pPopup;
    DWORD SelectionMade;
    menu.LoadMenu(IDR_MENU);
    pPopup = menu.GetSubMenu(0);
    RECT pp;
    CWnd *pWnd = GetDlgItem(IDC_MENUBUTTON);
    pWnd->GetWindowRect(&pp);
    SelectionMade = pPopup->TrackPopupMenu(TPM_LEFTALIGN | TPM_LEFTBUTTON,pp.right,pp.top,this);
    pPopup->DestroyMenu();    
}