Aspect Oriented Programming in ASP.NET MVC

Question

Im currently developing an MVC application in ASP.NET and I\'m trying to separate concerns so that I end up with cleaner and more maintanable code.

So, as a starting poi

Answer 1

You can use attributes to implement a feature in an aspect-oriented way. Action methods that you want to surround with your functionality then only need to be decorated with your attribute:

[CustomLogger]
public ActionResult Index()
{
    // Doing something here ...
    return View();
}

You can either decorate a single action method with an attribute, an entire controller, or even apply the attribute globally through ASP.NET MVC's GlobalFilterCollection.

Here's how you'd declare your attribute:

public class CustomLoggerAttribute : ActionFilterAttribute
{
    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        base.OnActionExecuted(filterContext);

        // Here goes your logic
    }

    // ...
}

The ActionFilterAttribute class allows you to override a couple of methods so you can hook into ASP.NET MVC's action execution pipeline:

• OnActionExecuting
• OnActionExecuted
• OnResultExecuting
• OnResultExecuted

You can access request variables through the parameters (like ActionExecutedContext) that are passed to the above methods.