How to "hook" into the pipe where the argument/object gets passed to the action-method

Question

Is there any way to alter the passed object to an action-method before it actually enters/(gets passed to) the action-metod?.. For instance... By default I want the Index()-action-method to always take an argument of MyClass..

So.. if a user visit mydomain.com/AController/

The triggerd action-method should be

public ActionResult Index(MyClass arg)
{ 
    return View();
}

Im not really sure of how to explain this.. but hopefully you get it.. What I actually want to do is the same thing that Umbraco does in thier MVC-project.. where they always pass-along a RenderModel-object, except that I want to have my own type not the RenderModel..

Thanks in advance!

Answer 1

As I understand your question, you want your action being invoked with a default arg value (if none is provided)

Considering your MyClass as :

public class MyClass 
{
    public int Id { get; set; }
    public string Name { get; set; }
}

You may define your route like :

        routes.MapRoute(
            name: "Default",
            url: "{controller}/{action}/{arg}",
            defaults: new { controller="Home",
                            action = "Index", 
                            arg = new MyClass() { Id = 1, Name = "test" } 
                      }
        );

I guess another option would be to have a custom ModelBinder or, at lower level, a custom ValueProvider.