how to get url from routing in asp.net?

I use routing in my web forms. for example:
routes.MapPageRoute("Home", "HomePage", "~/Default.aspx"); and I redirect to page with
Response.RedirectToRoute("Home"); now Is there a function (or solution) in asp.net that will give it route name [Home] (or URL parameters [HomePage]) and return original address (Default.aspx)?
or Is there a function (or solution) in asp.net that will give it URL parameters (HomePage) and return route name (Home)?
Thanks a lot.