HttpModules, and HttpHandlers

Question

Hi all, these days I am doing R&D about HttpModules, and HttpHandlers.

Part 1:

I have read that:

"While a request is being processed, each request is processed by multiple HTTP modules (for example, the authentication module and the session module)"

However; I have seen that developers does authentication work in their web form's code behind file.

please tell me why do we do authentication in web form's code behind if we do have already developed authentication HttpModule.

Part 2:

I am also confused about the process flow, I read that:

"All Http requests passes through no of HttpModules and then assigned to single HttpHandler, after running HttpHandler request again passes through those httpModules"

I want to know that at what point developers code (code written in the web form's code behind file) run in this atcivity.




any help in this regards would be heighly appreciated, thanks in advance.