如何动态地将指定数量的文本框添加到gridview？

Question

The code below allows users to add as many rows of textboxes to the gridview as needed.

We have decided to limit the number of rows a user adds dynamically to just 6.

I have googled the web looking for samples of how this is done to no avail.

Does anyone know what needs to change on the code below so that users can only add new rows of up to 6 but no more than 6?

Thanks a lot in advance

    Private Sub AddNewRow()
    Dim rowIndex As Integer = 0

    If ViewState("CurrentTable") IsNot Nothing Then
        Dim dtCurrentTable As DataTable = DirectCast(ViewState("CurrentTable"), DataTable)
        Dim drCurrentRow As DataRow = Nothing
        If dtCurrentTable.Rows.Count > 0 Then
            For i As Integer = 1 To dtCurrentTable.Rows.Count
                Dim TextRefillNumber As TextBox = DirectCast(grvStudentDetails.Rows(rowIndex).Cells(1).FindControl("txtRefillNumber"), TextBox)
                drCurrentRow = dtCurrentTable.NewRow()
                drCurrentRow("RowNumber") = i + 1

                dtCurrentTable.Rows(i - 1)("Col1") = TextRefillNumber.Text

                rowIndex += 1
            Next
            dtCurrentTable.Rows.Add(drCurrentRow)
            ViewState("CurrentTable") = dtCurrentTable

            grvStudentDetails.DataSource = dtCurrentTable
            grvStudentDetails.DataBind()

            Dim txn As TextBox = DirectCast(grvStudentDetails.Rows(rowIndex).Cells(1).FindControl("txtRefillNumber"), TextBox)
            ' txn.Focus;
            txn.Focus()
        End If
    Else
        Response.Write("ViewState is null")
    End If
    SetPreviousData()
End Sub
Private Sub SetPreviousData()
    Dim rowIndex As Integer = 0
    If ViewState("CurrentTable") IsNot Nothing Then
        Dim dt As DataTable = DirectCast(ViewState("CurrentTable"), DataTable)
        If dt.Rows.Count > 0 Then
            For i As Integer = 0 To dt.Rows.Count - 1
                Dim TextRefillNumber As TextBox = DirectCast(grvStudentDetails.Rows(rowIndex).Cells(1).FindControl("txtRefillNumber"), TextBox)
                ' drCurrentRow["RowNumber"] = i + 1;

                grvStudentDetails.Rows(i).Cells(0).Text = Convert.ToString(i + 1)
                TextRefillNumber.Text = dt.Rows(i)("Col1").ToString()
                rowIndex += 1
            Next
        End If
    End If
End Sub
Protected Sub ButtonAdd_Click(ByVal sender As Object, ByVal e As EventArgs)
    AddNewRow()
End Sub

Note: I added C# tag since I can convert from C# to VB.net

Answer 1

You should have a counter for the rows. When a user adds a row the counter will increase. If a user tries to add a row when counter >= limit do not allow it.

You should have an UserAddRow and UserRemoveRow methods which will take care of the counter increase and decrese. This will improve readability and maintainability .