Display the contents of a gridlookedit while writing

Hi friend and I have a gridlookedit and I am working on vb.net with component in devexpress and I want to know how I do to display the list box when receiving the focus and close it when the focus is lost

This way I charge the combo

Private Sub cmb_Nomb_EditValueChanged(sender As Object, e As EventArgs) Handles cmb_Nomb.EditValueChanged

    Dim dt As DataTable
    dt = Deduccion.combo_emp(cmb_Nomb.EditValue)
    If cmb_Nomb.EditValue IsNot Nothing Then
        Dim row As DataRow = Me.cmb_Nomb.Properties.View.GetDataRow(Me.cmb_Nomb.Properties.View.FocusedRowHandle)

        If row IsNot Nothing Then
            If dt.Rows.Count > 0 Then
                If row.Item("NO_EMP") = row.Item("NO_EMP") Then
                    txt_Ced.EditValue = dt.Rows(0).Item("CEDULA")
                    txtArea.EditValue = dt.Rows(0).Item("Des_Area")
                    txtCargo.EditValue = dt.Rows(0).Item("Des_Car")
                    txtcargos.EditValue = dt.Rows(0).Item("Cod_Area")
                    txtareas.EditValue = dt.Rows(0).Item("Cod_Car")
                    txtnoemp.EditValue = dt.Rows(0).Item("No_Emp")
                End If
            End If
        End If
    End If
End Sub