In My Dynamic Check Box Control, When I Put It In A For Loop To Create Control Based On Datatable Values, It Shows An Exception Error

For Each row As GridViewRow In gv.Rows
            If row.RowType = DataControlRowType.DataRow Then
                For j = 0 To dtop.Rows.Count - 1
                    Dim tf As New TemplateField()
                    Dim cb As New CheckBox
                    tf.HeaderText = "" & dtop.Rows(j)(0) & ""
                    gv.Columns.Add(tf)
                    row.Cells(j + 1).Controls.Add(cb)
                Next
            End If

        Next

row.Cells(j + 1).Controls.Add(cb). The exception is on this line and the exception is "Specified argument was out of the range of valid values. Parameter name: index"..