Handler Concept in ASP.NET
Some ASP.NET files are dynamically generated. They are generated with C# code or disk resources. These files do not require web forms. Instead, an ASHX generic handler is ideal. It can dynamically return an image from a query string, write XML, or any other data.
HTTP handlers are the .NET components that implement the System.Web.IHttpHandler interface. Any class that implements the IHttpHandler interface can act as a target for the incoming HTTP requests. HTTP handlers are somewhat similar to ISAPI extensions. One difference between HTTP handlers and ISAPI extensions is that HTTP handlers can be called directly by using their file name in the URL, similar to ISAPI extensions.
