How would you implement a breadcrumb helper in asp.net mvc?

Question

I know you could make a helper pretty easily given the data. So, if possible, please only submit answers that also include getting the data.

Answer 1

We are using an action filter for this.

...

 public override void OnActionExecuting(ActionExecutingContext filterContext)
 {
  var controller = (Controller) filterContext.Controller;
  Breadcrumb[] breadcrumbs = _breadcrumbManager.PushBreadcrumb(_breadcrumbLinkText);
  controller.ViewData.Add(breadcrumbs);
 }

before you mention it, I too have a distaste for service location in the filter attributes - but we are left with few options. IBreadcrumbManager looks like this:

public interface IBreadcrumbManager
{
 Breadcrumb[] PushBreadcrumb(string linkText);
}

The implementation puts Breadcrumb objects into the Session. The Url is HttpContext.Current.Request.RawUrl

Answer 2

How would you go about displaying the breadcrumbs in a View?

Answer 3

@Chris: something like this:

  <% 
     foreach (var item in ViewData.Get<Breadcrumb[]>())
   {
  %>
    <a href="<%= Server.HtmlEncode(item.Url) %>"><%= item.LinkText %></a> &raquo;
  <% 
   } 
  %>

Answer 4

Matt,

Would you be so kind to show a bit more of your suggested implementation, it intrigues and confuses me all at the same time ;)

For example, where do you instantiate the _breadcrumbManager, and what does it do internally?

Regards, avsomeren