It is advisable to start a new thread that will perform the task, allowing the first thread to return in the thread pool and stand-by to serve a new incoming request.

To reach our goal, no modifications are required to the actual codebase that is in charge to execute the task. In the second option we are going to use a Page's method that first registers an async task, passing three different event handlers: one to begin/launch the task, one to manage its completion and the last one used to recover from a timeout that may occur during the task execution.

This option also uses IAsyncResult interface described here, but no extra coding is needed to use it, take a look to the code sample.

The SimpleWorker class exposes one method that simulates a long running operation, but it only writes a text line into a log file and waits one second per each line. Imagine an order's fulfillment procedure that creates packing lists and sends an email to customers indicating that their orders are "approved."

Listing 1 - Using PageAsyncTask

PageAsyncTask task = new PageAsyncTask(OnBegin, OnEnd, OnTimeout, null);
Page.RegisterAsyncTask(task);
TraceStatusInfo("TEST CASE #2: Start a long running task asynchronously using 
PageAsyncTask.");
//Setting up a 5 secs timeout
Page.AsyncTimeout = new TimeSpan(0, 0, 5);
TraceStatusInfo("Starting task");
Page.ExecuteRegisteredAsyncTasks();

If such a procedure is started from an ASP.NET page, it is a good practice to maintain an activity registry or log because the web application could be suddenly stopped without any warning and the worker process may be recycled due to excessive and unexpected resource consumption.