Paging and routing in ASP.Net MVC - asp.net-mvc

Question

I am following Martijn Boland's 'Paging with ASP.NET MVC'. And while helpful it has raised a couple of issues I don't understand.
Martijn says:
Internally, the pager uses
RouteTable.Routes.GetVirtualPath() to
render the url’s so the page url’s can
be configured via routing to create
nice looking url’s like for example
‘/Categories/Shoes/Page/1′ instead of
‘/Paging/ViewByCategory?name=Shoes&page=1′.
This is the is what he is talking about:
private string GeneratePageLink(string linkText, int pageNumber)
{
var pageLinkValueDictionary = new RouteValueDictionary(this.linkWithoutPageValuesDictionary);
pageLinkValueDictionary.Add("page", pageNumber);
//var virtualPathData = this.viewContext.RouteData.Route.GetVirtualPath(this.viewContext, pageLinkValueDictionary);
var virtualPathData = RouteTable.Routes.GetVirtualPath(this.viewContext.RequestContext, pageLinkValueDictionary);
if (virtualPathData != null)
{
string linkFormat = "{1}";
return String.Format(linkFormat, virtualPathData.VirtualPath, linkText);
}
else
{
return null;
}
}
How does this work? When I use it virtualPathData.VirtualPath just brings back a url representing the first route in my routing table with a 'page' param on the end rather then a url representing the current context.
Also what would the routing look like to change this ‘/Paging/ViewByCategory?name=Shoes&page=1′ to this ‘/Categories/Shoes/Page/1′ ?

Answer 1

I assume You have Paging controller and this controller has ViewByCategory action.
ViewByCategory looks like:
public ActionResult ViewByCategory(string categoryName, int? page)
{
....
}
Routing will look like
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
routes.MapRoute(
"RouteByCategory",
"Categories/{categoryName}/Page/{page}",
new { controller = "Paging", action = "ViewByCategory" }
);
routes.MapRoute(
"RouteByCategoryFirstPage",
"Categories/{categoryName}",
new { controller = "Paging", action = "ViewByCategory", page = 1 }
);
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = "" } // Parameter defaults
);
}
protected void Application_Start()
{
RegisterRoutes(RouteTable.Routes);
}
GeneratePageLink will return link in ‘/Categories/Shoes/Page/1′ format, because it is first matching route pattern in routing table.