Chapter 2Controllers

—by Jon Galloway

What's In This Chapter?

  • Understanding the controller's role
  • Setting up a sample application: The MVC Music Store
  • Controller 101

This chapter explains how controllers respond to user HTTP requests and return information to the browser. It focuses on the function of controllers and controller actions. We haven't covered views and models yet, so our controller action samples will be a little high level. This chapter lays the groundwork for the following several chapters.

Chapter 1 discussed the Model-View-Controller (MVC) pattern in general and then followed up with how ASP.NET MVC compares with ASP.NET Web Forms. Now it's time to get into a bit more detail about one of the core elements of the three-sided pattern that is MVC—the controller.

THE CONTROLLER'S ROLE

Starting out with a quick definition and then diving into detail from there is probably best. Keep this definition in mind while reading this chapter. It can help to ground the discussion ahead with what a controller is all about and what it's supposed to do.

Controllers within the MVC pattern are responsible for responding to user input, often making changes to the model in response to user input. In this way, controllers in the MVC pattern are concerned with the flow of the application, working with data coming in, and providing data going out to the relevant view.

Way back in the day, web servers served up HTML stored in static files on disk. As dynamic web pages gained prominence, ...

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