ASP.NET MVC - Twitter Bootstrap navbar link helper

HtmlHelpers.cs

using System.Web.Mvc.Html;

public static class HtmlHelpers
{
	public static MvcHtmlString MenuLink(this HtmlHelper htmlHelper, string linkText, string actionName, string controllerName)
	{
		var currentAction = htmlHelper.ViewContext.RouteData.GetRequiredString("action");
		var currentController = htmlHelper.ViewContext.RouteData.GetRequiredString("controller");

		var builder = new TagBuilder("li")
						  {
							  InnerHtml = htmlHelper.ActionLink(linkText, actionName, controllerName).ToHtmlString()
						  };

		if (controllerName == currentController && actionName == currentAction)
			builder.AddCssClass("active");			

		return new MvcHtmlString(builder.ToString());
	}
}

Thanks! But it doesn't work for ASP.NET Core anymore.
I've just updated it: https://gist.github.com/biehlermi/934509124eb726cefc4b833996c53420