Llenar un combobox por dataset c#

Combobox_con_dataset.cs

public void LlenarComboMotivos()
        {
            try
            {
                //this.cbMotivo.Items.Clear();
                this.cbMotivo.DataSource = null;
                OracleDataAdapter daEmp = new OracleDataAdapter("select  IDMOT, MOTNUM||' : '||MOT AS MOT, MOTNUM, FECREG, USENAM, HOSTNAME from SIA_MOTIVOS  order by MOTNUM asc", cls_DatosLolcli.cadenaconexion);
                DataSet dsEmp = new DataSet("SIA_MOTIVOS");
                daEmp.Fill(dsEmp, "SIA_MOTIVOS");
                DataTable dtEmp = dsEmp.Tables["SIA_MOTIVOS"];
                DataRow[] drEmp = dsEmp.Tables["SIA_MOTIVOS"].Select();

                if (dsEmp.Tables[0].Rows.Count > 0)
                {
                    this.cbMotivo.DataSource = dsEmp.Tables[0].DefaultView;
                    this.cbMotivo.DisplayMember = "MOT";
                    this.cbMotivo.ValueMember = "MOTNUM";
                }
            }
            catch (Exception ex)
            {
                throw;
            }



        }