ASP.NET MVC Action Methods are responsible to execute requests and generate responses to it. By default, it generates a response in the form of ActionResult. Actions typically have a one-to-one mapping with user interactions.

For example, enter a URL into the browser, click on any particular link, and submit a form, etc. Each of these user interactions causes a request to be sent to the server. In each case, the URL of the request includes information that the MVC framework uses to invoke an action method. The one restriction on action method is that they have to be instance method, so they cannot be static methods. Also there is no return value restrictions. So you can return the string, integer, etc.

Request Processing

Actions are the ultimate request destination in an MVC application and it uses the controller base class. Let’s take a look at the request processing.

When a URL arrives, like /Home/index, it is the UrlRoutingModule that inspects and understands that something configured within the routing table knows how to handle that URL.

  1. The UrlRoutingModule puts together the information we’ve configured in the routing table and hands over control to the MVC route handler.
  2. The MVC route handler passes the controller over to the MvcHandler which is an HTTP handler.
  3. MvcHandler uses a controller factory to instantiate the controller and it knows what controller to instantiate because it looks in the RouteData for that controller value.
  4. Once the MvcHandler has a controller, the only thing that MvcHandler knows about is IController Interface, so it simply tells the controller to execute.
  5. When it tells the controller to execute, that’s been derived from the MVC’s controller base class. The Execute method creates an action invoker and tells that action invoker to go and find a method to invoke, find an action to invoke.
  6. The action invoker, again, looks in the RouteData and finds that action parameter that’s been passed along from the routing engine.

Types of Action

Actions basically return different types of action results. The ActionResult class is the base for all action results. Following is that the list of various quite action results and its behavior.

  •  ContentResult Returns a string
  •  FileContentResult Returns file content
  •  FilePathResult Returns file content
  •  FileStreamResult Returns file content
  •  EmptyResult Returns nothing
  •  JavaScriptResult Returns script for execution
  •  JsonResult Returns JSON formatted knowledge
  •  RedirectToResult Redirects to the desired uniform resource locator
  •  HttpUnauthorizedResult Returns 403 protocol standing code
  •  RedirectToRouteResult Redirects to completely different action/different controller action
  •  ViewResult Received as a response for read engine
  •  PartialViewResult Received as a response for read engine

Let’s have a glance at a straightforward example from the previous chapter within which we’ve got created AN EmployeeController.

using System;
using System.Collections.Generic;
using System.Linq;

using System.Web;
using System.Web.Mvc;

namespace MVCControllerActionDemo.Controllers {
   public class EmployeeController : Controller{
      // GET: Employee
      public ActionResult Search(string name){
         var input = Server.HtmlEncode(name);
         return Content(input);
      }
   }
}

When you request the following URL http://localhost:52361/Employee/Pawan, then you will receive the following output as an action.

Localhost Employee PawanOutput
Add Controller
Let us add each other controller.

Step One − Right-click on Controllers folder and choose Add → Controller..
Step Two − Choose the MVC five Controller – Empty possibility and click on ‘Add’ button.
Step Three − Set the name to User Controller and click on ‘Add’ button.

Now you’ll see a replacement C# file ‘UserController.cs’ within the Controllers folder, that is open for writing in Visual Studio still.
Similarly, add an added controller with name HomeController. Following is that the HomeController.cs category implementation.

using System;
using System.Collections.Generic;
using System.Linq;

using System.Web;
using System.Web.Mvc;

namespace MVCControllerActionDemo.Controllers {
   public class HomeController : Controller{
      // GET: Home
      public string Index(){
         return "This is Home Controller";
      }
   }
}

Step Four − Run this application and you will receive the following output.
Step Five − Add the following code in User controller, which we have created above.

public string GetAllUsers(){
   return @"<ul>
      <li>Pawan</li>
      <li>Rohit</li>
      <li>Haider</li>
   </ul>";
}

Step Six − Run this application and request for http://localhost:52361/User/GetAllUsers. You will see the following output.

Localhost GetAllUsers
You can also redirect to actions for the same controller or even for a different controller.

Following is a simple example in which we will redirect from HomeController to User Controller by changing the code in HomeController using the following code.

using System;
using System.Collections.Generic;
using System.Linq;

using System.Web;
using System.Web.Mvc;

namespace MVCControllerActionDemo.Controllers{
   public class HomeController : Controller{
      // GET: Home
      public ActionResult Index(){
         return RedirectToAction("GetAllUsers","User");
      }
   }
}

As you’ll see, we’ve got used the RedirectToAction() technique ActionResult, that takes 2 parameters, action name and controller name.

When you run this application, you will see the default route will redirect it to /User/GetAllUsers

Leave a Reply

Your email address will not be published. Required fields are marked *