Adding “active” tag to navigation list in an asp.net mvc master page

I made myself a helper method to handle this type of thing. In the code behind of my master page (could be pushed of to an extension method … probably a better approach), I put the following code.

protected string ActiveActionLinkHelper(string linkText, string actionName, string controlName, string activeClassName)
{
    if (ViewContext.RouteData.Values["action"].ToString() == actionName && 
            ViewContext.RouteData.Values["controller"].ToString() == controlName)
        return Html.ActionLink(linkText, actionName, controlName, new { Class = activeClassName });

    return Html.ActionLink(linkText, actionName, controlName);
}

Then, I just call it in my page like so:

<%= ActiveActionLinkHelper("Home", "Index", "Home", "selected")%>