ASP.net MVC - Navigation and highlighting the "current" link

Check out this blog post

It shows how to create an HTML Extension that you call instead of the usual Html.ActionLink The extension then appends class="selected" to the list item that is currently active.

You can then put whatever formatting/highlighting you want in your CSS

EDIT

Just adding some code to rather than just a link.

public static class HtmlHelpers
{

    public static MvcHtmlString MenuLink(this HtmlHelper htmlHelper,
                                        string linkText,
                                        string actionName,
                                        string controllerName
                                        )
    {

        string currentAction = htmlHelper.ViewContext.RouteData.GetRequiredString("action");
        string currentController = htmlHelper.ViewContext.RouteData.GetRequiredString("controller");

        if (actionName == currentAction && controllerName == currentController)
        {
            return htmlHelper.ActionLink(linkText, actionName, controllerName, null, new { @class = "selected" });
        }

        return htmlHelper.ActionLink(linkText, actionName, controllerName);


    }
} 

Now you need to define your selected class in your CSS and then in your views add a using statement at the top.

@using ProjectNamespace.HtmlHelpers

And use the MenuLink instead of ActionLink

@Html.MenuLink("Your Menu Item", "Action", "Controller")

You could do this by using "data-" attributes to identify the container(s) then using jQuery change CSS class of the link, like the following:

<div class="..." data-navigation="true">
                    <ul class="...">
                        <li>@Html.ActionLink("About", "About", "Home")</li>
                        <li>@Html.ActionLink("Contact", "Contact", "Home")</li>
                    </ul>
</div>

<script>
    $(function () {
        $("div[data-navigation='true']").find("li").children("a").each(function () {
            if ($(this).attr("href") === window.location.pathname) {
                $(this).parent().addClass("active");
            }
        });
    });
</script>