Url.routeUrl returns null (I've tried same questions)

Question

Hi everyone I wanna get url like {Controller}/{action}/{postid}-{address} but routUrl returns null please help me to solve it.(I'm newbie in MVC)

my route config is

routes.MapRoute(
            name: "Post",
            url: "Posts/Show/{postid}-{address}",
            defaults: new { controller = "Posts", action = "Index", postid = "", address = "" }
           );

and index.cshtml

<a href="@Url.RouteUrl("Post",new {item.PostId,item.Address })">@item.PostTitle</a>

the url that generate is http://localhost:59066/Posts/Show/1-Post-with-Featured-Image

but in PostsController

public ActionResult Show(string add)
    { return View();} 

"string add" is null !

Answer 1

I changed the route to

routes.MapRoute("Post", "post/{postid}-{address}", new { controller = "Posts", action = "Show" ,postid="",address=""}, namespaces);

and added a route with same controller and action

routes.MapRoute("PostAddress", "post/{IdAndAdd}", new { controller = "Posts", action = "Show" }, namespaces);
routes.MapRoute("Post", "post/{postid}-{address}", new { controller = "Posts", action = "Show" ,postid="",address=""}, namespaces);

then action received "idAndAdd" correctly

public ActionResult Show(string idAndAdd)
    {
        var parts = SeperateAddress(idAndAdd);
        if (parts == null)
            return HttpNotFound();

        var post = db.Posts.Find(parts.Item1);
        if (post == null)
            return HttpNotFound();

        if (!post.Address.Equals(parts.Item2, StringComparison.CurrentCultureIgnoreCase))
            return RedirectToRoutePermanent("Post", new { postid = parts.Item1, address = post.Address });

        return View(post);
    }

    and it's worked .