ASP.NET MVC Action Filters: Controlling Controller Behavior and Enhancing Application Logic

Learn how to use action filters in ASP.NET MVC to modify the behavior of controller actions. This tutorial covers built-in filters (like `OutputCache` and `Authorize`), demonstrates their implementation, and explains how to create custom filters for handling cross-cutting concerns like caching, authorization, and exception management.

ASP.NET MVC Action Filters: Controlling Controller Behavior

Introduction to Action Filters

Action filters in ASP.NET MVC provide a mechanism to modify the behavior of controller actions. They're attributes you can apply to individual actions or entire controllers to intercept and modify the request processing pipeline. This allows for centralized handling of cross-cutting concerns like caching, error handling, and authorization.

Types of Action Filters in ASP.NET MVC

ASP.NET MVC provides several built-in action filters:

• OutputCache: Caches the output of an action method for a specified duration.
• HandleError: Handles exceptions that occur during action method execution.
• Authorize: Restricts access to authorized users only.

OutputCache Action Filter Example

This example demonstrates using the OutputCache attribute to cache the output of an action method for 10 seconds.

using System;
using System.Web.Mvc;
namespace MvcApplicationDemo.Controllers
{
public class MusicStoreController : Controller
{
    [OutputCache(Duration = 10)]
    public ActionResult Index()
    {
        return View();
    }
}
}

@{
    Response.Write(DateTime.Now.ToString("T"));
}

Authorize Action Filter Example

This example uses the Authorize attribute to restrict access to an action method to authorized users only. Unauthorized users will be redirected to the login page.

using System;
using System.Web.Mvc;
namespace MvcApplicationDemo.Controllers
{
public class MusicStoreController : Controller
{
    [Authorize]
    public ActionResult Index()
    {
        return View();
    }
}
}