ขอความรู้เรื่องการทำ Running Number หน่อยครับ ช่วยชี้แนะทีครับ

Dim s As String = Microsoft.VisualBasic.Right(Now.Year, 2) & (CDbl("62800") + 1)
TextBox1.Text = s

Private Sub GenDetailID()
        Dim con As SqlConnection
        Dim cmd As New SqlCommand
        Dim strConnString As String = "data source= ............"
        con = New SqlConnection(strConnString)
        cmd.CommandType = CommandType.Text
        cmd.Connection = con
        cmd.CommandText = "Select Max (DetailNo) from [tbTest_OrdersDetail]"
        con.Open()
        Dim a As Integer = cmd.ExecuteScalar
        con.Close()
        lblDetailNo.Text = a + 1
        If lblDetailNo.Text = "" Then

        End If
    End Sub