Routing in MVC not working - asp.net-mvc

Question

I have the following route:
routes.MapRoute(
"Property",
"{language}/property/{propertyUrlId}",
new { controller = "PropertyDetails", action = "Property" }
This is the Controller that should be called for that route:
public class PropertyDetailsController : Controller
{
public ActionResult Property(string language, string propertyUrlId)
{
etc.
And the following URL that should use that route:
http://domain.com/en-us/property/3
Instead, I get 404. Any ideas why?
Here are my routes:
public static void RegisterRoutes(RouteCollection routes)
{
routes.MapRoute(
"Property",
"property/{propertyUrlId}",
//new { controller = "PropertyDetails", action = "Property" }, new { language = #"[a-zA-Z]{2}-[a-zA-Z]{2}" }
new { controller = "PropertyDetails", action = "Property" }
);
}
Didn't work with language, or with language/country, either.

Answer 1

You most likely have registered the default route before your Property route. Default route typically looks like this:
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
);
Just register your Property route BEFORE this default route and it will work.
Why it fails? (Assuming you are indeed registering default route first)
en-us -> is interpreted as controller
property -> is interpreted as action
Since you don't have a en-usController with a Property action -> 404

Answer 2

Use "en-us" as a segment of the URL is completely fine. I guess you have registered other routes as well. Try to bring this route to the top of others and at least on top of the default route.
I have tested the scenario, it works just fine for me.

Answer 3

Considering that you want to have the structure of the url as:
http://domain.com/en-us/property/3
use this routing:
routes.MapRoute(
"Property", // Route name
"{language}/property/{propertyUrlId}", // URL with parameters
new { controller = "PropertyDetails", action = "Property", propertyUrlId = UrlParameter.Optional } // Parameter defaults
);
if there is a default routing in your Global.asax file, like this:
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
);
Put the routint above this block of code.
And your Controller Action should look like this:
public ActionResult Property(int propertyUrlId)
{
return View();
}

Answer 4

First of all, there is no reason to break {language} apart into two chunks in the route. As some of you stated, this is fine:
routes.MapRoute(
"Property",
"{language}/property/{propertyUrlId}",
new { controller = "PropertyDetails", action = "Property" }
Second, I omitted some information which was crucial to the solving of this problem. It didn't occur to me to include this in my problem description, as I didn't know there was any relationship. The MVC project is in a solution which also contains a website (non-MVC) which is using the Sitecore CMS as its datastore. Sitecore was stripping out the language segment of the URL and storing it, itself. Once I learned that this was happening, I was able to deal with the problem.
I appreciate all the input, and I apologize for the confusion.