Attribute Routing difference?

Question

What is the difference between the following?

[Route("movies/genre/{genre}")]
public ActionResult ViewByGenre(string genre="action")

Instead of

[Route("movies/genre/{genre=action}")]
public ActionResult ViewByGenre(string genre)

Answer 1

in this statment

[Route("movies/genre/{genre}")]
public ActionResult ViewByGenre(string genre="action")

genre parameter isn't optional in the route, only ViewByGenre function will valorize it.

here

[Route("movies/genre/{genre=action}")]
public ActionResult ViewByGenre(string genre)

you are saying that genre parameter is optional in the route. If it arrives null it will take action value. ViewByGenre function always should have genre parameter valorized

refer here for documentation

In this way you are doing attribute routing. The advantages are that Attribute Routing gives you more control over the URI in the applications, when you edit something in the code it won't break another route. On the other side an example of Convention base rules is when you decide your rules in the RouteConfig.cs file like this

public static void RegisterRoutes(RouteCollection routes)
{
    routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

    routes.MapMvcAttributeRoutes();

    routes.MapRoute(
        name: "Default",
        url: "{controller}/{action}/{id}",
        defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
    );
}