GetDlgCtrlID does not return anything

BOOL CSend_DataDlg::OnToolTipNotify( UINT id,
                                  NMHDR * pNMHDR,
                                  LRESULT * pResult )
{
	
	AFX_MODULE_THREAD_STATE* pModuleThreadState =AfxGetModuleThreadState();
	//if(pModuleThreadState)
	{
		CToolTipCtrl* pToolTip = pModuleThreadState->m_pToolTip;
		if(pToolTip)
		pToolTip->SetMaxTipWidth(130);
	}
    // Get the tooltip structure.
    TOOLTIPTEXT *pTTT = (TOOLTIPTEXT *)pNMHDR;
 
    // Actually the idFrom holds Control's handle.
    UINT CtrlHandle = pNMHDR->idFrom;
	
 
    // Check once again that the idFrom holds handle itself.
    if ((pTTT->uFlags & TTF_IDISHWND))
    {
        // Get the control's ID.
        UINT nID = ::GetDlgCtrlID( HWND( CtrlHandle ));
        // Now you have the ID. depends on control,
        // set your tooltip message.
		CString str;
		str.Format("%i", nID);
		AfxMessageBox(str);
//this is just to check if the ID is read
		switch( nID )
        {
			//activate button
	    case IDC_MAP_1:
                pTTT->lpszText = _T("Write curves of map 1");
            break;
	    case IDC_MAP_2:
		pTTT->lpszText = _T("Write curves of map 2");
            break;
        }
    }
}