Using Generic Handler or .ashx file instead of heavyset web form (.aspx) is a lighter-weight and faster way to handle certain types of Http request, such as rendering an large image, spit out text files, etc. I recently used it in one web project that needed to setup a Http listener to process incoming requests and not doing any Html rendering.

By default, an .ashx file (Generic Handler template from VS2010) code behind automatically added these namespaces only:

 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

 

Then when I tried to store a session_id from incoming Http request’s querystring in the Session object of HttpContext.Current, and it failed. As it turned out, in order to access Session object, I needed to add a SessionState namespace, System.web.SessionState; and then implement the IRequiresSessionState interface. the beginning of the .ashx code behind now looked like this:

 

 

public class ServeRequest : IHttpHandler, IRequiresSessionState

{

 

public void ProcessRequest(HttpContext context)

{

 

//codes to handle Http request

}

}