asp.net table adding rows dynamically don't remain after postback

I have a button click event that adds text to a table. However, when I submit the form the values entered into the table don't appear in the postback... is this possible to do?

Here is my code:

    Protected Sub AddRowToInputTables(table As Table, value As String)
    If table IsNot Nothing Then
        Dim id As String = value.Trim()
        Dim prefix As String = ""
        If (table.ID = "cust_num") Then ' todo - abstract this out and use a parameter for the prefix instead
            prefix = "CN"
        Else
            prefix = "RN"
        End If
        If id <> String.Empty Then
            Dim tr = New TableRow()
            Dim td = New TableCell()
  开发者_开发知识库          Dim td2 = New TableCell()
            Dim btnDelete = New ImageButton()
            btnDelete.ID = "btn" & prefix & "_" & id & "_del"
            btnDelete.ImageUrl = "http://res.xxxxxxxx.net/images/delete.png" ' todo - put this in the web.config or settings file
            tr.ID = id
            td.Text = id
            td2.Controls.Add(btnDelete)
            tr.Cells.Add(td)
            tr.Cells.Add(td2)
            Dim rows = New List(Of TableRow)()
            For Each row In table.Rows
                rows.Add(row)
            Next
            rows.Add(tr)
            table.Rows.Clear()
            table.Rows.AddRange(rows.ToArray())
            cust_num_txt.Value = String.Empty
            res_num_txt.Value = String.Empty
        End If
    End If
End Sub

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You will either need to commit the table to ViewState or Session, or recreate the table every time the page is posted back. If the table isn't too large, you can probably just throw it in ViewState.

To save the table to ViewState:

ViewState["MyTable"] = table;

To retrieve the table from ViewState:

table = (DataTable)ViewState["MyTable"];

---

Trick is to populate the table in the Load event only... then everything started working normally.

---

I had the same problem and the following solution worked well :

sub AddRowsToTable()
    session("MyTable") = Nothing
    MyTable.Rows.Clear
    '... Adding rows and cells here ...
end sub

Protected Sub btnRefreshTable_Click(sender As Object, e As ImageClickEventArgs) Handles btnRefreshTable.Click
    AddRowsToTable()
    Session("MyTable") = MyTable
End Sub

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    If Page.IsPostBack Then
        If Not IsNothing(Session("MyTable")) Then
            AddRowsToTable()
        End If
    End If
End Sub

hope this help