In ASP.NET MVC 2 - How do I get Route Values into my navigation controller so I can highlight the current link?

Question

I'm trying to get the current Route into my navigation controller so I can run comparisons as the navigation menu data is populated.

My Links object is like this:

public class StreamNavLinks
{
    public string Text { get; set; }
    public RouteValueDictionary RouteValues { get; set; }
    public bool IsSelected { get; set; }
}

In the master page, I'm trying to pass the current route to the nav controller like this:

<% Html.RenderAction(
    "MenuOfStreamEntries", // action
    "Nav", // controller
    new { // parameters for action
        currentStreamUrl = "Blog", 
        currentRoute = ViewContext.RouteData } // get route data to compare in controller
); %>

The problem that I'm running into is that I can't figure out how to get any of the data out of currentRoute. What is the best technique for getting the values out or currentRoute?

I've tried syntax like this:

 currentRoute.Values.routevaluename

and

 currentRoute.Values[0]

But I can't seem to get it to work.

Edit

I have also tried placing this code into the action of the navigation controller:

var current = RouteData["streamUrl"];

and

var current = this.RouteData["streamUrl"];

Both versions give me this error:

Error 1 Cannot apply indexing with [] to an expression of >type 'System.Web.Routing.RouteData' C:\pathtocontroller\NavController.cs 25 27

Edit 2

It also might be helpful to know the route values that I'm trying to match against:

        routes.MapRoute(null, "", // Only matches the empty URL (i.e. ~/)
                        new
                        {
                            controller = "Stream",
                            action = "Entry",
                            streamUrl = "Pages",
                            entryUrl = "HomePage"
                        }
        );

        routes.MapRoute(null, "{streamUrl}/{entryUrl}", // matches ~/Pages/HomePage
                        new { controller = "Stream", action = "Entry" }
        );

So, ultimately mydomain.com/blog/blogentry1 would map to the same controller/action as mydomain.com/pages/welcome. I'm not looking for the controller value or the action value, rather I'm looking for streamUrl value and EntryUrl value.

Answer 1

You don't need to pass route data to a controller because the controller already has knowledge of it via the RouteData property:

public ActionResult Index() {
    // You could use this.RouteData here
    ...
}

Now if you want to pass some simple arguments like current action that was used to render the view you could do this:

<%= Html.RenderAction(
    "MenuOfStreamEntries",
    "Nav",
    new {
        currentStreamUrl = "Blog", 
        currentAction = ViewContext.RouteData.Values["action"],
        currentController = ViewContext.RouteData.Values["controller"]
    }
); %>

And in your controller:

public ActionResult Nav(string currentAction, string currentController) 
{
    ...
}

Answer 2

Taken from this good article.

Create a custom extension method:

public static class HtmlExtensions
{
    public static MvcHtmlString ActionMenuItem(this HtmlHelper htmlHelper, String linkText,
        String actionName, String controllerName)
    {
        var tag = new TagBuilder("li");

        if ( htmlHelper.ViewContext.RequestContext
            .IsCurrentRoute(null, controllerName, actionName) )
        {
            tag.AddCssClass("selected");
        }

        tag.InnerHtml = htmlHelper.ActionLink(linkText, actionName, controllerName).ToString();

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

Your HTML markup:

<div id="menucontainer">

    <ul id="menu">
        <%= Html.ActionMenuItem("Home", "Index", "Home") %>
        <%= Html.ActionMenuItem("About", "About", "Home") %>
    </ul>

</div>

Produces the following output:

<div id="menucontainer">

    <ul id="menu">
        <li class="selected"><a href="/">Home</a></li>
        <li><a href="/Home/About">About</a></li>
    </ul>

</div>

Answer 3

Here's a sample method we wrote for doing something similar.

public static bool IsCurrentAction(this HtmlHelper helper, string actionName, string controllerName)
{
  string currentControllerName = (string)helper.ViewContext.RouteData.Values["controller"];
  string currentActionName = (string)helper.ViewContext.RouteData.Values["action"];

  return currentControllerName.Equals(controllerName, StringComparison.CurrentCultureIgnoreCase) && currentActionName.Equals(actionName, StringComparison.CurrentCultureIgnoreCase));
}