Question

Suppose I have defined route like that,

        context.MapRoute(
            "Preview",
            "/preview/{id}/{type}",
            new { controller = "Preview", action = "Invoice", id = UrlParameter.Optional, type = UrlParameter.Optional }
        );

I have controller with action Invoice

public ActionResult(int id, string type)
{
  if (type == "someType") 
  {
    // ...
  } 
  else
  {
    // ..
  }
}

I want to get rid of If-Else case inside the action. Is it possible to attribute action somehow, so ASP.MVC would distinguish between both, like:

Just a pseudocode tho show idea?

[HttpGet, ActionName("Action"), ForParameter("type", "someType")]
public ActionResult PreviewSomeType(int id) {}

[HttpGet, ActionName("Action"), ForParameter("type", "someType2")]
public ActionResult PreviewSomeType2(int id) {}

Is something like that possible in MVC2/3 ?

Answer 1

Action method selector

What you need is an Action Method Selector that does exactly what you’re describing and are used exactly for this purpose so that’s not a kind of a workaround as it would be with a different routing definition or any other way. Custom action method selector attribute is the solution not a workaround.

I’ve written two blog posts that will get you started with action method selection in Asp.net MVC and these kind of attributes:

• Improving Asp.net MVC maintainability and RESTful conformance
  this particular post shows an action method selector that removes action method code branches what you’d also like to accomplish;
• Custom action method selector attributes in Asp.net MVC
  explains action method selection in Asp.net MVC to understand the inner workings of it while also providing a selector that distinguishes normal vs. Ajax action methods for the same request;