问在ASP .NET MVC 3中使用子域路由生成URL

EN

public static IHtmlString AdvRouteLink(this HtmlHelper htmlHelper, string linkText, string routeName, object routeValues, object htmlAttributes)
{
    RouteValueDictionary routeValueDict = new RouteValueDictionary(routeValues);
    var request = htmlHelper.ViewContext.RequestContext.HttpContext.Request;
    string host = request.IsLocal ? request.Headers["Host"] : request.Url.Host;
    if (host.IndexOf(":") >= 0)
        host = host.Substring(0, host.IndexOf(":"));

    string url = UrlHelper.GenerateUrl(routeName, null, null, routeValueDict, RouteTable.Routes, htmlHelper.ViewContext.RequestContext, false);
    var virtualPathData = RouteTable.Routes.GetVirtualPathForArea(htmlHelper.ViewContext.RequestContext, routeName, routeValueDict);

    var route = virtualPathData.Route as SubdomainRoute;

    string actualSubdomain = SubdomainRoute.GetSubdomain(host);
    if (!string.IsNullOrEmpty(actualSubdomain))
        host = host.Substring(host.IndexOf(".") + 1);

    if (!string.IsNullOrEmpty(route.Subdomain))
        host = string.Concat(route.Subdomain, ".", host);
    else
        host = host.Substring(host.IndexOf(".") + 1);

    UriBuilder builder = new UriBuilder(request.Url.Scheme, host, 80, url);

    if (request.IsLocal)
        builder.Port = request.Url.Port;

    url = builder.Uri.ToString();

    return htmlHelper.Link(linkText, url, htmlAttributes);
}

private static IHtmlString Link(this HtmlHelper htmlHelper, string text, string url, object htmlAttributes)
{
    TagBuilder tag = new TagBuilder("a");
    tag.Attributes.Add("href", url);
    tag.InnerHtml = text;
    tag.MergeAttributes(HtmlHelper.AnonymousObjectToHtmlAttributes(htmlAttributes));
    return MvcHtmlString.Create(tag.ToString(TagRenderMode.Normal));
}