问Dropdown在运行时缺少一个listItem

EN

Sub LoadMerchant()

        Try
            Utilities.GetTerminal(ddlMerchant, -999, -999, "-999", "-999", "-999")
            ddlMerchant.Items.Insert(0, New ListItem("Select", -999))
            ddlMerchant.SelectedIndex = 0

        Catch ex As Exception

        End Try
    End Sub

 objBox.Items.Clear()
            Try
                Dim drTemp As SqlDataReader = GenericDB.ExecuteSPForDataReader("spGetTerminal", CountryID, CityID, MerchantID, TerminalID, POSSerial)
                While drTemp.Read()
                    Dim sTerminal As String = ""
                    sTerminal = drTemp.Item("TerminalID") + " : " + Convert.ToString(drTemp.Item("MerchantName1"))
                    objBox.Items.Add(New ListItem(sTerminal, drTemp.Item("TerminalID")))
                End While
                objBox.SelectedIndex = 0
                drTemp.Close()

            Catch ex As Exception
                Throw ex
            End Try