asp.net mvc MenuLink extension

MenuLinkExtension.cs

public static MvcHtmlString MenuLink(
    this HtmlHelper helper, 
    string text, string action, string controller)
{            
    var routeData = helper.ViewContext.RouteData.Values;
    var currentController = routeData["controller"];
    var currentAction = routeData["action"];             
 
    if(String.Equals(action, currentAction as string,
              StringComparison.OrdinalIgnoreCase)
        &&
       String.Equals(controller, currentController as string,
               StringComparison.OrdinalIgnoreCase))
        
    {
       return helper.ActionLink(
           text,action, controller, null,
           new { @class="currentMenuItem"}
           );
    }
    return helper.ActionLink(text, action, controller);
}