Dynamic Navigation

        public static MvcHtmlString SideNavigationTab(this HtmlHelper htmlHelper, string tabName, string linkText, string actionName, string controllerName,
                                                      Func<dynamic, MvcHtmlString>[] subMenu = null, string area = "", string clientid = "")
        {
            var dt = new TagBuilder("dt");

            if (!String.IsNullOrEmpty(clientid))
                dt.Attributes.Add("id", clientid);

            if ((string)HttpContext.Current.Items["CURRENT_TAB_NAME"] == tabName)
                dt.AddCssClass("active");

            var link = htmlHelper.ActionLink(linkText, actionName, controllerName, new {area=""}, null);

            dt.InnerHtml = String.Format("<span class=\"marker\"></span>{0}", link);

            if (subMenu == null)
                return MvcHtmlString.Create(dt.ToString());

            var subList = new TagBuilder("dd");
            foreach (var sub in subMenu)
                subList.InnerHtml += sub(null).ToString();


            return MvcHtmlString.Create(dt.ToString() + subList);
        }

        public static MvcHtmlString SideSubNavigationTab(this HtmlHelper htmlHelper, string tabName, string linkText, string actionName, string controllerName, string area = "", string clientid = "")
        {
            var div = new TagBuilder("div");

            if ((string)HttpContext.Current.Items["CURRENT_TAB_NAME"] == tabName)
                div.AddCssClass("active");

            var link = htmlHelper.ActionLink(linkText, actionName, controllerName, new { area = "" }, null);
            div.InnerHtml = link.ToString();

            return MvcHtmlString.Create(div.ToString());
        }