Dynamic control Viewstate

Question

I am now stuck. After spending ages trying to maintain dynamically added linkbutton or label to a gridview it seems I am overwriting a checkbox state on post back.

As stated I am dynamically adding either a linkbutton or a label to a place holder in a gridview with the following:

protected void LedgerGrid_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            int index = e.Row.RowIndex;

            if (items[index].noteID > 0)
            {

                PlaceHolder label = (PlaceHolder)e.Row.FindControl("HasPrevious");
                LinkButton link = new LinkButton();
                link.CommandName = "LinkCommand";
                link.Command += new CommandEventHandler(link_Command);
                link.Text = "Yes";
                link.ID = index.ToString();
                label.Controls.Add(link);

            }
            else
            {
                PlaceHolder label = (PlaceHolder)e.Row.FindControl("HasPrevious");
                Label noNote = new Label();
                noNote.Text = "No";
                label.Controls.Add(noNote);
            }

Here is the gridview:

<asp:GridView runat="server" ID="LedgerGrid" AutoGenerateColumns="false" 
    onselectedindexchanged="LedgerGrid_SelectedIndexChanged" 
    onrowdatabound="LedgerGrid_RowDataBound" onrowcommand="LedgerGrid_RowCommand" 
    >
<Columns>
<asp:TemplateField HeaderText="Notes">
<ItemTemplate>
  <asp:PlaceHolder ID="HasPrevious" runat="server"></asp:PlaceHolder>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField HeaderText="Invoice Date" DataField="invoicedate" DataFormatString="{0:d}" />
<asp:BoundField HeaderText="Invoice" DataField="invoice" />
<asp:BoundField HeaderText="Fee Debt" DataField="Fee_Debt" DataFormatString="{0:C}" />
<asp:BoundField HeaderText="Cost Debt" DataField="Cost_Debt" DataFormatString="{0:C}" />
<asp:BoundField HeaderText="VAT Debt" DataField="VAT_Debt" DataFormatString="{0:C}" />
<asp:BoundField HeaderText="Total Debt" DataField="Total_Debt" DataFormatString="{0:C}" />
<asp:BoundField HeaderText="Client Code" DataField="ClientCode" />
<asp:ButtonField  HeaderText="Matter Number" DataTextField="matternumber" CommandName="ViewMatter" />
<asp:BoundField HeaderText="Decription" DataField="matterdescription" />
<asp:TemplateField>
<ItemTemplate>
<asp:CheckBox ID="AddInvoiceCheck" runat="server" Enabled="true" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>

To make sure that my link button command works I am rebuilding the gridview as I would in the Page_load. Here is the page load:

 protected void Page_Load(object sender, EventArgs e)
    {

        if (!IsPostBack)
        {

            string clientCode = Server.HtmlEncode(Request.QueryString["clientcode"]);
            items = DataAccess.DataAccess.GetLedgerDetails(clientCode);
            ViewState["LedgerItems"] = items;
            ViewState["clientcode"] = clientCode;
            LedgerGrid.DataSource = items;
            LedgerGrid.DataBind();
            LedgerClientObject clientDetails = DataAccess.DataAccess.GetClientDetails(clientCode);
            ClientCodeLabel.Text = string.Format("Group Code: {0}", clientDetails.GroupCode);
            ClientNameLabel.Text = string.Format("Client Name: {0}", clientDetails.ClientName);
            ClientCodeFilter.DataSource = clientDetails.ClientCodes;
            ClientCodeFilter.DataBind();


        }
    } 

To maintain the dynamically added controls on post back I am calling the following:

protected void Page_PreLoad(object sender, EventArgs e)
    {


        if (IsPostBack)
        {
            items = (List<LedgerItem>)ViewState["LedgerItems"];
            LedgerGrid.DataSource = items;
            LedgerGrid.DataBind();


        }


    }

Of course it now seems that by using this method I am overwriting the state of the check-box gridview column. Am I approaching this all wrong? I would like to be able to use the viewstate to maintain the set up of my dynamically added controls to the gridview. Is there a way I can access the state of the checkbox control form gridview before/after I reload the gridview in PreLoad event?

I am checking the state of my checkbox column with a button click as follows:

        protected void Unnamed1_Click(object sender, EventArgs e)
    {
        NoteModel note = new NoteModel();
        for (int i = 0; i < LedgerGrid.Rows.Count; i++)
        {
            int invoice = Convert.ToInt32(LedgerGrid.Rows[i].Cells[2].Text);
            CheckBox check = (CheckBox)LedgerGrid.Rows[i].FindControl("AddInvoiceCheck");
            if (check.Checked)
            {
                note.invoices.Add(invoice);

            }



        }

        if (note.invoices == null)
        {

            string clientcode = (string)ViewState["clientcode"];
            ViewState["InvoiceError"] = 1;
            Response.Redirect(string.Format("Ledger.aspx?clientcode={0}", clientcode));
        }
        else
        {
            string clientcode = (string)ViewState["clientcode"];
            Session["NoteObject"] = note;
            Response.Redirect(string.Format("AddNote.aspx?cc={0}", clientcode));

        }


    }

Whenever I iterate over the checkbox controls in the gridview they are all unchecked e.g overwritten by my PreLoad code!!!

Answer 1

In the end I decided not to use dynamically created controls. Instead I added a buttonfield to the grid view. In my rowdatabound event I then set the visibility of the button to false if it does meet my criteria. This way view state is maintained as i do not need to create control on post back.

Seems with webforms that avoiding dynamic controls where possible is the best bet. I would still like to know which event to tap into to override viewstate re-instating controls?