Question

In ASP.Net MVC if I have a method on a controller that returns a View should that method be of type ViewResult or the more general ActionResult?

Answer 1

A similar question was asked on the ASP.NET forums: http://forums.asp.net/t/1423519.aspx

Basically, it comes down to style — in OOP, you try to return the most specific type that you can given the situation. You don’t return object for every method that you have — sometimes you return string, sometimes List, sometimes a custom class.

In the forum replies, someone quotes Stephen Walther from his book:

NOTE This action method specifically
declares that it returns an instance
of ViewResult. It would work just the
same if instead the method return type
was ActionResult (the base class for
all action results). In fact, some
ASP.NET MVC programmers declare all
their action methods as returning a
nonspecific ActionResult, even if they
know for sure that it will always
return one particular subclass.
However, it’s a well-established
principle in object-oriented
programming that methods should return
the most specific type they can (as
well as accepting the most general
parameter types they can). Following
this principle maximizes convenience
and flexibility for code that calls
your method, such as your unit tests.

So using the more specific ViewResult would be preferred, especially from a unit testing perspective.