Asp.Net Custom Routing and custom routing and add category before controller

Yes, this is possible. First, you must create a RouteConstraint to insure that a brand has been chosen. If a brand has not been chosen, this route should fail, and a route to an action to redirect to the brand selector should follow. The RouteConstraint should look like this:

using System; 
using System.Web;  
using System.Web.Routing;  
namespace Examples.Extensions 
{ 
    public class MustBeBrand : IRouteConstraint 
    { 
        public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection) 
        { 
            // return true if this is a valid brand
            var _db = new BrandDbContext();
            return _db.Brands.FirstOrDefault(x => x.BrandName.ToLowerInvariant() == 
                values[parameterName].ToString().ToLowerInvariant()) != null; 
        } 
    } 
} 

Then, define your Routes as follows (assuming that your brand selector is the home page):

routes.MapRoute( 
    "BrandRoute",
    "{controller}/{brand}/{action}/{id}",
    new { controller = "News", action = "Index", id = UrlParameter.Optional }, 
    new { brand = new MustBeBrand() }
); 

routes.MapRoute( 
    "Default",
    "",
    new { controller = "Selector", action = "Index" }
); 

routes.MapRoute( 
    "NotBrandRoute",
    "{*ignoreThis}",
    new { controller = "Selector", action = "Redirect" }
); 

Then, in your SelectorController:

public ActionResult Redirect()
{
    return RedirectToAction("Index");
}

public ActionResult Index()
{
    // brand selector action
}

If your home page is not the brand selector, or there is other non-brand content on the site, then this routing is not correct. You will need additional routes between BrandRoute and Default which match routes to your other content.