Debugging ASP.Net AJAX Pages

If you've done any ASP.Net AJAX development, you've probably run into the following error message while debugging (Sys.WebForms.PageRequestManagerTimeoutException: The server request timed out):

This happens because the default timeout for asynchronous processing is 90 seconds. This is a reasonable default, and really, nothing in an asynchronous request should take that long. However, if you're stepping through code of any complexity, you can easily exceed that limit. You can fix this by setting the timeout on your script manager, like this:

<asp:ScriptManager ID="MainScriptManager" runat="server" EnablePartialRendering="true" AsyncPostBackTimeout="3600" />

However, you probably don't want that in production. There is also a way to set this in your code-behind, and do it conditionally, based on whether your pages are running in debug mode or not. If you've been doing ASP.Net development for any amount of time you are probably aware that you shouldn't run your production site in with debug enabled in the web.config file. So, how do you tell if that is enabled? In that link, Scott Guthrie mentions that you can use HttpContext.Current.IsDebuggingEnabled to tell. So, the code to set this would look like this:

// if we're running debug mode, increase the async timeout to 1 hour.
// this allows stepping through code without timing out on the front end.
if (HttpContext.Current.IsDebuggingEnabled)
{
MainScriptManager.AsyncPostBackTimeout = 3600;
}

This only increases the timeout if you're running in debug mode. I've implemented this in one of our products, and it has worked great.