รบกวนสอบถาม ERROR การรันไอดีอัตโนมัติแบบมีตัวอักษรผสมค่ะ

    Private Sub GenID() 'ใช้รันรหัสDivisionID

        Dim IDGen As Integer = 0
        Dim Conn As New SqlConnection(webConnect)

        Dim sql_text As String = " SELECT TOP 1 DivisionID FROM tblDivision ORDER BY DivisionID DESC"
        'Dim sql_text As String = "  Select Max(Right(DivisionID,5)) as DivisionID from tblDivision "
        Dim Cmd As New SqlCommand(sql_text)
        Cmd.CommandType = CommandType.Text
        Cmd.Connection = Conn
        Dim sda As New SqlDataAdapter
        Dim dt As New DataTable

        Try
           Conn.Open()
            sda.SelectCommand = Cmd
            sda.Fill(dt)

            If dt.Rows.Count > 0 Then
                IDGen = CInt(dt.Rows(0)("DivisionID"))  '<------ ERROR พอเข้าลูปนี้
                IDGen = IDGen + 1
                Gen = "DV" & IDGen.ToString("0000")
            Else
                Gen = "DV" & "0001"

            End If

        Catch ex As Exception
            MsgBox(ex.Message)
        Finally
            Conn.Close()
            sda.Dispose()
            Conn.Dispose()
        End Try

    End Sub

 Private Sub GenID() 'ใช้รันรหัสDivisionID

        Dim IDGen As String = 0 '<-----ลองทั้งแบบ sting และ int ก็ยังไม่ได้ค่ะ
        Dim Conn As New SqlConnection(webConnect)

        Dim sql_text As String = " SELECT TOP 1 DivisionID FROM tblDivision ORDER BY DivisionID DESC"
       
        Dim Cmd As New SqlCommand(sql_text)
        Cmd.CommandType = CommandType.Text
        Cmd.Connection = Conn
        Dim sda As New SqlDataAdapter
        Dim dt As New DataTable

        Try
           Conn.Open()
            sda.SelectCommand = Cmd
            sda.Fill(dt)


            If dt.Rows.Count > 0 Then
   
                IDGen = CStr(dt.Rows(0)("DivisionID")) '<----- ลองทั้งแบบ sting และ int ก็ยังไม่ได้ค่ะ
                IDGen = IDGen + 1                 
                Gen = "DV" & IDGen.ToString("0000")   ' ตัว Gen ประกาศค่า  Dim Gen As String = "" 
            Else
                Gen = "DV" & "0001"

            End If

        Catch ex As Exception
            MsgBox(ex.Message)
        Finally
            Conn.Close()
            sda.Dispose()
            Conn.Dispose()
        End Try

    End Sub