TemplateColumns disappearing from GridView

[Justin115]

I'm dynamically adding columns to a GridView which contains two declaratively-defined TemplateFields which each contain a LinkButton. When I add the new columns after the TemplateColumns, everything works fine. But when I insert the columns into the beginning of the GridView's columns collection, all of the TemplateFields disappear when I click on one of the LinkButtons!

What's going on here?

Thanks in advance for whatever help you can provide,
-Justin

<%@ Page Language="VB" AutoEventWireup="false"
	CodeFile="test.aspx.vb" Inherits="test" Title="Untitled Page" %>

<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
	<asp:Label ID="lblCommandName" runat="server" Text="(Command name)"></asp:Label>
	<asp:GridView runat="server" ID="myGridView" AutoGenerateColumns="False">
		<Columns>
			<asp:TemplateField ShowHeader="False">
				<ItemTemplate>
					<asp:LinkButton ID="btnSomething" runat="server" CausesValidation="False" CommandName="Something"
						Text="Do something"></asp:LinkButton>
				</ItemTemplate>
			</asp:TemplateField>
			<asp:TemplateField ShowHeader="False">
				<ItemTemplate>
					<asp:LinkButton ID="btnSomethingElse" runat="server" CausesValidation="False" CommandName="Something else"
						Text="Do something else"></asp:LinkButton>
				</ItemTemplate>
			</asp:TemplateField>
		</Columns>
	</asp:GridView>	
</asp:Content>

Imports System.Data

Partial Class test
	Inherits System.Web.UI.Page

	Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
		If Not Page.IsPostBack Then
			Dim ds As New DataSet()
			Dim dt As New DataTable("tbl")
			dt.Columns.Add(New DataColumn("data", GetType(String)))
			dt.Rows.Add("abc")
			dt.Rows.Add("123")
			ds.Tables.Add(dt)
			myGridView.DataSource = ds

			Dim field As New BoundField()
			field.DataField = "data"

			'This works:
			myGridView.Columns.Add(field)

			'But this doesn't:
			myGridView.Columns.Insert(0, field)

			myGridView.DataBind()
		End If
	End Sub

	Protected Sub myGridView_RowCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs) Handles myGridView.RowCommand
		lblCommandName.Text = e.CommandName
	End Sub
End Class

 

[jbenson001]

Try adding the dynamic columns in the Page_Init event instead of the Page_Load event.

Jim

 

[Justin115]

I thought it had a good chance, but it didn't work. I tried all of the events in the page lifecycle, and aside from PreInit throwing an error, the rest acted the same as PageLoad.

 

[tperri]

Look at this article:

http://msdn.microsoft.com/library/d...webservercontroltemplatesprogrammatically.asp

Or this one that is less verbose:

http://msdn.microsoft.com/library/d...atingwebservercontroltemplatesdynamically.asp

 

[Justin115]

Is there something specific in those two articles you thought I should look at? They both seem to be about creating templates programatically, which isn't what I'm trying to do.

I guess I could try dynamically generating all of my fields, including the two template fields--that may have been what you meant. I'd rather leave it how it is if I can get it to work, but it's an option I hadn't considered before.

Thanks for the links.

 

[Justin115]

Someone on the ASP.Net forums helpfully gave me the solution. My code needs to go not in Page.Init, but in myGridView.Init. That makes all the difference in the world.

Thanks for the help, everyone.