ASP.NET MVC Controller Actions and Parameters: Handling User Requests

Understand how to define and utilize controller actions and parameters in ASP.NET MVC. This tutorial explains routing, action method return types (`ActionResult`, `ViewResult`, etc.), handling different request types, and passing parameters to controller actions for building dynamic and responsive web applications.

ASP.NET MVC Controller Actions and Parameters

Controller Actions and User Requests

In ASP.NET MVC, controllers handle user requests and return responses (typically views). A controller contains multiple action methods, each designed to handle a specific type of request (e.g., displaying a page, processing form data). User requests can come from various sources (typing a URL, clicking a link, submitting a form). The MVC framework uses routing rules (defined in Global.asax.cs) to map the incoming URL to the appropriate controller and action.

ActionResult Return Types

Action methods in ASP.NET MVC return an instance of the ActionResult class or a derived type. The specific type depends on what the action needs to do:

Adding an Action Method

To add a new action method to a controller, you define a public method within the controller class. Here's an example of adding a "Welcome" action to the MusicStoreController:

using System.Web.Mvc;
namespace MvcApplicationDemo.Controllers
{
public class MusicStoreController : Controller
{
    public ActionResult Index() { return View(); }
    public string Welcome() { return "Hello, this is a welcome message."; }
}
}

Action Method Parameters

Action methods can accept parameters to receive data from the user's request (URL parameters, form data, etc.). The MVC framework maps values from the request to the action method's parameters.

using System.Web.Mvc;
namespace MvcApplicationDemo.Controllers
{
public class MusicStoreController : Controller
{
    public ActionResult Index() { return View(); }
    public string ShowMusic(string MusicTitle) { return "You selected " + MusicTitle + " Music"; }
}
}