Friday, February 13, 2009

Disable user interface during ajax postbacks on ASP.Net

One of the biggest issues I have with public facing websites I work on is double clicks on buttons or users interrupting the postback process. This happens a lot with the payment button of credit card transactions and other time consuming postbacks.
I have done some Javascript and CSS tweaks and tricks to handle specific controls and I was unable to get something I was truely happy with.
Until I met jQuery. jQuery is a javascript library that does a whole bunch of things, introduces shortend syntax and a pluggable API. It can be downloaded at
Coupling JQuery with a plugin called BlockUI. Can be downloaded at
What I came out with is a fairly generic solution for ASP.Net that handles all the ajax postbacks for a specific page or website by wiring the application_beginRequest and application_endRequest on the client side.
So here is the recipe:
Ingrediants -
1. ASP.Net 3.5 website
2. An aspx webpage
3. A script manager with a reference to:

  1. The JQeury library

  2. Block UI plugin

  3. A very short Javascipt file (enclosed below)

4. An update panel


1. Create your website - I use Visual Studio 2008

2. Add your page or your master page

3. Create a js directory and add the downloaded scripts from jQuery and JBlockUI

4. Add a new file to the js directory called wireRequestEvents.js

with the following code:


function BeginRequestHandler(sender, args)
function EndRequestHandler(sender, args)

5. Drop a script manager in your page with the following syntax:

6. Add your update panels with contect templates and you are good to go.

To demonstrate the technique I created a simple page with a button and a label inside an update panel. Once clicked the button waits 4 seconds and then changes the label. This imulates a long transaction on the server.

Here is what the users will see:

After they click the button the UI is blocked by a semi transperant div

When the request returns the users will see the updated screen

Pretty simple!

The code for this is available at