draft - subdomain route with constraints

gistfile1.cs

//Usage:
context.Routes.Add("Site_Home", new SubdomainRoute(
    "",
    "",
    new { area = this.AreaName, controller = "Home", action = "Index" },
    new { httpMethod = new HttpMethodConstraint("GET") },
    new string[] { "SubdomainRouting.Areas.Site.Controllers" }
));

//Custom Route:
public class SubdomainRoute : Route, IRouteWithArea
{
    private string[] namespaces;
    public string Subdomain { get; private set; }

    public SubdomainRoute(string subdomain, string url, object defaults, string[] namespaces)
        : this(subdomain, url, defaults, new { }, namespaces)
    {

    }

    public SubdomainRoute(string subdomain, string url, object defaults, object constraints, string[] namespaces)
        : base(url, new RouteValueDictionary(defaults), new RouteValueDictionary(constraints), new MvcRouteHandler())
    {
        this.Subdomain = subdomain;
        this.namespaces = namespaces;
    }

    public string Area
    {
        get { return Convert.ToString(this.Defaults["area"]); }
    }

    private bool ProcessConstraints(HttpContextBase httpContext, RouteValueDictionary values, RouteDirection routeDirection)
    {
        if (Constraints != null)
        {
            foreach (var constraintsItem in Constraints)
            {
                if (!ProcessConstraint(httpContext, constraintsItem.Value, constraintsItem.Key, values, routeDirection))
                {
                    return false;
                }
            }
        }
        return true;
    }

    public override RouteData GetRouteData(HttpContextBase httpContext)
    {
        string requestPath = httpContext.Request.AppRelativeCurrentExecutionFilePath.Substring(2) + httpContext.Request.PathInfo;
        string requestDomain = GetSubdomain(httpContext.Request.Headers["Host"]);

        RouteData data = null;
        Regex domainRegex = CreateRegex(this.Subdomain);
        Regex pathRegex = CreateRegex(this.Url);
        Match domainMatch = domainRegex.Match(requestDomain);
        Match pathMatch = pathRegex.Match(requestPath);

        if (domainMatch.Success && pathMatch.Success)
        {
            data = new RouteData(this, RouteHandler);

            if (Defaults != null)
            {
                foreach (KeyValuePair<string, object> item in Defaults)
                    data.Values[item.Key] = item.Value;
            }
                
            if (!this.ProcessConstraints(httpContext, data.Values, RouteDirection.IncomingRequest))
                return null;

            for (int i = 0; i < pathMatch.Groups.Count; i++)
            {
                Group group = pathMatch.Groups[i];
                if (group.Success)
                {
                    string key = pathRegex.GroupNameFromNumber(i);

                    if (!string.IsNullOrEmpty(key) && !char.IsNumber(key, 0))
                    {
                        if (!string.IsNullOrEmpty(group.Value))
                        {
                            data.Values[key] = group.Value;
                        }
                    }
                }
            }

            data.DataTokens.Add("Area", data.Values["area"]);
            data.DataTokens.Add("namespaces", this.namespaces);
        }

        return data;
    }

    public static string GetSubdomain(string host)
    {
        if (host.IndexOf(":") >= 0)
            host = host.Substring(0, host.IndexOf(":"));

        Regex tldRegex = new Regex(@"\.[a-z]{2,3}\.[a-z]{2}$");
        host = tldRegex.Replace(host, "");
        tldRegex = new Regex(@"\.[a-z]{2,4}$");
        host = tldRegex.Replace(host, "");

        if (host.Split('.').Length > 1)
            return host.Substring(0, host.IndexOf("."));
        else
            return string.Empty;
    }

    private Regex CreateRegex(string source)
    {
        source = source.Replace("/", @"\/?");
        source = source.Replace(".", @"\.?");
        source = source.Replace("-", @"\-?");
        source = source.Replace("{", @"(?<");
        source = source.Replace("}", @">([a-zA-Z0-9_-]*))");
        return new Regex("^" + source + "$");
    }
}

Eu tentei implementar esse código em VB.net da seguinte forma

context.Routes.Add("Telefonia_default", New SubdomainRoute("telefonia", "telefonia.planetavr.com.br", New With { _
.area = Me.AreaName, .controller = "LinksUteis", .action = "Index" _
}, New With { _
.httpMethod = New HttpMethodConstraint("GET") _
}, New String() {"SubdomainRouting.Areas.Site.Controllers"}))

esta correto?? pois não consegui fazer funcionar.