Database not getting updated

Protected Sub btnInsert_Click(sender As Object, e As EventArgs) Handles btnInsert.Click
        Dim dt As New DataTable()
        dt.Columns.Add("TDSMRANGE")
      

        For Each row As GridViewRow In gdTDSM.Rows
                Dim TDSMRANGE As Integer = row.Cells(0).Text
                dt.Rows.Add(TDSMRANGE)
        Next

        If dt.Rows.Count > 0 Then
            Try
                Using sqlBulkCopy As New SqlBulkCopy(connection)
                    'Set the database table name
                    sqlBulkCopy.DestinationTableName = "dbo.TDSM"

                    If connection.State = ConnectionState.Closed Then
                        connection.Open()
                    End If
                    Try
                        sqlBulkCopy.WriteToServer(dt)

                    Catch ex As Exception
                        fnMessage(Me, ex.Message)
                    End Try
                    connection.Close()

                End Using
            Catch EX As Exception
                fnMessage(Me, EX.Message)
            End Try
        End If


    End Sub