title: ASP.NET MVC: Register action filter without modifying controller
body: <p>I'm working with nopCommerce and I need to add in my only Action Filter, however, I don't want to modify the core controllers to avoid my code being overwritten when a new update is released.</p>
  
  <p>I've setup my Action Filter:</p>
  
  <pre><code>public class ProductActionFilterAttribute : ActionFilterAttribute
  {
  
      public override void OnActionExecuted(ActionExecutedContext filterContext)
      {
          if (filterContext.Result is ViewResult)
          {
              ...
          }
          base.OnActionExecuted(filterContext);
      }
  
  }
  </code></pre>
  
  <p>If I were to modify the controller, I could just add <code>[ProductActionFilter]</code> to the action I want it assigned to.</p>
  
  <p>Is there a way I can register my custom Action Filter to a specific action without modifying the controller?</p>