Another simple place to hook your stuff in to the framework is action filters. An action filter is an attribute that derives from ActionFilterAttribute which is a convenience class containing the following methods for you to override:

void OnActionExecuting(ActionExecutingContext context);
void OnActionExecuted(ActionExecutedContext context);
void OnResultExecuting(ResultExecutingContext context);
void OnResultExecuted(ResultExecutedContext context);

A lot of the examples around the internet show how to use action filters to restrict access to controller actions or how to apply caching. I won’t do that here, because those concerns are boring. No, we care about how to make life easy for ourselves and how to write testable, non-breakable, maintenance-and-wrist-friendly code. That is, we reserve the right to be lazy.

A fine example on how to be lazy is by letting action filters fetch data for you to avoid repetitive repository gymnastics in every controller action – and I am actually going to be very lazy right now, because I wrote two posts on this topic earlier:

1. How to avoid duplicate data fecthing with ASP.NET MVC
2. Another way to avoid duplicate data fetching with ASP.NET MVC