System.Web.Mvc.ActionFilterAttribute vs System.Web.Http.Filters.ActionFilterAttribute

Question

i see that there are two version of ActionFilterAttribute class.
System.Web.Mvc.ActionFilterAttribute and System.Web.Http.Filters.ActionFilterAttri

Answer 1

System.Web.Mvc.ActionFilterAttribute is intended for use with ASP.NET MVC. System.Web.Http.Filters.ActionFilterAttribute is intended for use with ASP.NET Web API.

MVC is web applications, Web API is HTTP services.

Their msdn pages are System.Web.Mvc.ActionFilterAttribute and System.Web.Http.Filters.ActionFilterAttribute