Trouble with global.asax routing - asp.net-mvc-3

Question

I have some links in my webapp that looks like this:
localhost:12345/?something=1
localhost:12345/?something=2
localhost:12345/?something=3
localhost:12345/?something=4
each number at the end is an id that i need to pass to my controller to display information related to it.
I know I need to create a new routes.MapRoute in my global.asax page, but I am not really quite sure how to go about it. I tried this:
routes.MapRoute(
"Id", // Route name
"{controller}/{action}/{*Id}", // URL with parameters
new { controller = "Home", action = "Id", Id = "" } // Parameter defaults
);
---EDIT---
I am only successful getting each individual like to display by doing the following:
routes.MapRoute(
"IdRoute", // Route name
"{Id}", // URL with parameters
new { controller = "Home", action = "Index", id = 1 } // Parameter defaults
);
This does work, however, this only works for one id (specifically 1). I am not quite sure how to go about this, but i need i need:
localhost:12345/?something=1
to display the information for id 1,
localhost:12345/?something=2
to display the information for id 2,
localhost:12345/?something=3
to display the information for id 3.
I there are going to be hundreds of ids so hard coding something in would not be a convenient option. I have had no luck so far. Any help would be much appreciated! Thanks!

Answer 1

routes.MapRouteWithName(
"RootName",
"{id}",
new { controller = "Home", action = "Index", id = 1 });
This will produce links like this localhost/1
If you want this kind of links localhost/?id= 1
Then :
routes.MapRouteWithName(
"RootName",
String.Empty,
new { controller = "Home", action = "Index"});
public ActionResult Index(int id)
{
//do something with id, make query to database whatever
// u usually have model class so you would fill model with your data
var model = new YourModel();
//...
return View("Index", model);
}

Answer 2

If you have following Action in, say, HomeController:
public ActionResult SomeAction(int Id)
{
return View()
}
You may use any of following routes:
//* For Id = 3 this will return path "Home/SomeAction/3"
routes.MapRoute(
name: "First",
url: "{controller}/{action}/{Id}",
defaults: new { controller = "Home", action = "SomeAction", Id= UrlParameter.Optional}
);
//* For Id = 3 this will return path "SomeAction/3"
routes.MapRoute(
name: "First",
url: "{action}/{Id}",
defaults: new { controller = "Home", action = "SomeAction", Id= UrlParameter.Optional}
);
//* For Id = 3 this will return path "Home/SomeAction(3)"
routes.MapRoute(
name: "First",
url: "{controller}/{action}({Id})",
defaults: new { controller = "Home", action = "SomeAction", Id= UrlParameter.Optional}
);
//* For Id = 3 this will return path "LadyGaga/SomeAction/3"
routes.MapRoute(
name: "First",
url: "LadyGaga/{action}/{Id}",
defaults: new { controller = "Home", action = "SomeAction", Id= UrlParameter.Optional}
);