ขอความช่วยเหลือ รันเล่มที่ เลขที่ใบเสร็จ vb 2008 sql 2005

 Protected Sub autoid()
        Dim dv As DataView
        Dim sum As Integer
        Dim sqlTmp As String

        Dim yyyy As String = CStr(Now.Year + 543)
        Dim mm As String = CStr(Now.Month)
        sqlTmp = "Select MAX(durStf_ann_id) as durStf_ann_id from tb_mate_durStf_ann1 "

        dv = ObjDb.GetDataSet(sqlTmp).Tables(0).DefaultView

        If dv.Count > 0 Then

            Dim newID As Integer = CInt(dv.Table.Rows(0)(0).ToString().Substring(7))
            newID = newID + 1

            'MsgBox(sum)

            txtdurStf_ann_id.Text = yyyy & "/" & "0" & mm & "-" & newID.ToString("0000")
        Else
            txtdurStf_ann_id.Text = yyyy & "/" & "0" & mm & "-" & "0001"
        End If

    End Sub