Uploading and returning files in an ASP.NET MVC application is very simple. The POSTed file(s) are available as parameters directly in actions through model binding. The files in the server can be easily sent as response to the clients through its rich support of action results.

There are already articles written on this subject. So why another article? Well, in this article I gathered the important concepts that are scattered in different posts, threads in a single place. I'm sure this article will help the MVC programmers to increase their grip on the framework.

As the name, Controller factory is the component responsible for searching and creating controllers. Like many other components, ASP.NET MVC has a built-in factory named DefaultControllerFactory that's pretty sufficient for most of our cases.

Searching a controller is a perform intensive job and the DefaultControllerFactory does some efficient caching mechanism to avoid looking for controllers every time when there is a need. In this article we are going to explore how the DefaultControllerFactory searches for a controller and what kind of strategies it uses to do the process efficiently.

Knowing how the DefaultControllerFactory works will help when we go for creating a custom factory. First we will see the basics then we slowly dive into the inner workings of the factory and its dependencies.