ashx files in asp.net

Handlers are meant for direct action they dont have any user interface hence no corresponding aspx web form.

 

the code behind in an asp.net project is executed only by receiving a web form request, but except for a handler which can be directly invoked without the need for a web form.

 

you can use a ashx handler in case of doing some programming work as a result of some actions on some other page or link in an email, etc.

 

possible use-cases:

* you can call a handler to fetch some data and give some file output to user to save it

* some sort of background processing, like image resizing or something, the result of it can be shown to user on another web page.

* unsubscibe email actions

* password resets by clicking on a link and in background you auto-generate  some password and send user password in email

 

If you see the journey of asp.net, then in asp.net mvc the code behind is executed first in controller, which can be somewhat compared to ashx handlers.