Javascript – ASP.NET AJAX: Firing an UpdatePanel after the page load is complete

I'm sure this is easy but I can't figure it out:

I have an ASP.NET page with some UpdatePanels on it. I want the page to completely load with some 'Please wait' text in the UpdatePanels. Then once the page is completely loaded I want to call a code-behind function to update the UpdatePanel.

Any ideas as to what combination of Javascript and code-behind I need to implement this idea?


PS: I've tried putting my function call in the Page_Load but then code is run before the page is delivered and, as the function I want to run takes some time, the page simply takes too long to load up.

Best Answer

I fiddled around with the ScriptManager suggestions - which I reckon I would have eventually got working but it seems to me that the Timer idea is easier to implement and not really(!) that much of a hack?!

Here's how I got my panel updated after the initial page render was complete...


    <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="AJAXPostLoadCall._Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">

<html xmlns="" >
<head runat="server">
    <title>Untitled Page</title>
    <form id="form1" runat="server">
    <h2>And now for a magic trick...</h2>
    <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="True">
            <asp:UpdatePanel ID="UpdatePanel1" runat="server">
                    <asp:Timer ID="Timer1" runat="server" Interval="2000" ontick="Timer1_Tick" />
                    <asp:Label ID="Label1" runat="server">Something magic is about to happen...</asp:Label>


and the code behind default.aspx.cs reads

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

namespace AJAXPostLoadCall
    public partial class _Default : System.Web.UI.Page

        protected void Page_Load(object sender, EventArgs e)

        public void DoMagic()
            Label1.Text = "Abracadabra";

        protected void Timer1_Tick(object sender, EventArgs e)
            // Do the magic, then disable the timer
            Timer1.Enabled = false;


So, the page loads up and the Timer (contained within the UpdatePanel) fires 2 secs after the page has loaded up (I think - I'm not sure when the Timer actually starts?). The label text is rewritten and then the Timer is disabled to stop any more updates.

Simple enough - but can you purists out there tell me if this is a Horrible Hack?