I done a htmlhelper but I can not get it to work tho. I did like I seen on different tutorials.

my MenuItemHelper static Class

public static string MenuItem(this HtmlHelper helper, string linkText, string actionName, string controllerName)
    {
        var currentControllerName = (string)helper.ViewContext.RouteData.Values["controller"];
        var currentActionName = (string)helper.ViewContext.RouteData.Values["action"];

        var sb = new StringBuilder();

        if (currentControllerName.Equals(controllerName, StringComparison.CurrentCultureIgnoreCase) && currentActionName.Equals(actionName, StringComparison.CurrentCultureIgnoreCase))
            sb.Append("<li class=\"selected\">");
        else
            sb.Append("<li>");

        sb.Append(helper.ActionLink(linkText, actionName, controllerName));
        sb.Append("</li>");
        return sb.ToString();
    }

import namespace

<%@ Import Namespace="MYAPP.Web.App.Helpers" %>

Implementation on my master.page

<%= Html.MenuItem("TEST LINK", "About", "Site") %> 

Errormessage I get

Method not found: 'System.String System.Web.Mvc.Html.LinkExtensions.ActionLink(System.Web.Mvc.HtmlHelper, System.String, System.String, System.String)