软电话来电应答

void CGuoTsapiDlg::OnButtonAnswercall()
{
    // TODO: Add your control notification handler code here
   
    int ret = m_Tsapiconnectorctrl1.TsAnswerCall();
        if(ret == 0)
        {
            SetDlgItemText(IDC_EDIT_MESSAGE,"answercall sucess");
            SetDlgItemText(IDC_EDIT_STATUS,"answercall");
        }
        else
            SetDlgItemText(IDC_EDIT_MESSAGE,m_Tsapiconnectorctrl1.GetErrorMessage());
}

TsAnswerCall中如何获取来电的ID号码？
拜求！