Better way to get active page link in MVC 3 Razor

A better approach is to use a HTML helper:

using System.Web.Mvc; 
using System.Web.Mvc.Html;

public static class MenuExtensions
{
    public static MvcHtmlString MenuItem(
        this HtmlHelper htmlHelper, 
        string text,
        string action, 
        string controller
    )
    {
        var li = new TagBuilder("li");
        var routeData = htmlHelper.ViewContext.RouteData;
        var currentAction = routeData.GetRequiredString("action");
        var currentController = routeData.GetRequiredString("controller");
        if (string.Equals(currentAction, action, StringComparison.OrdinalIgnoreCase) &&
            string.Equals(currentController, controller, StringComparison.OrdinalIgnoreCase))
        {
            li.AddCssClass("active");
        }
        li.InnerHtml = htmlHelper.ActionLink(text, action, controller).ToHtmlString();
        return MvcHtmlString.Create(li.ToString());
    }
}

and then:

<ul>
    @Html.MenuItem("Home", "Home", "Home")
    @Html.MenuItem("Products", "Index", "Products")
</ul>

To make the above work you need your views to recognize your extension: In Web.config in the Views folder, add <add namespace="yourNamespacehere.Helpers" /> inside the namespaces tag. Then build your project and close and re-open the view you are adding this to.

then based on the current action and controller the helper will add or not the active class when generating the anchor.