title: ViewBag empty in ActionFilter OnActionExecuted
body: <p>I have a requirement to log a user's journey through an ASP.NET MVC application. I am using a global ActionFilter and log4net. I need to be able to read values (specifically <code>ViewBag.Title</code>) from the ViewBag which have been set in the view. At the moment the ViewBag is coming back empty.</p>
  
  <pre><code>public class UserActivityFilter : IActionFilter
  {
      public void OnActionExecuted(ActionExecutedContext filterContext)
      {
          var properties = new Dictionary&lt;string, string&gt;();
          if (filterContext.Result is ViewResult)
          {
              var action = filterContext.Result as ViewResult;
              properties.Add("Page.Title", action.ViewBag.Title);
          }
          // Log4net stuff goes here
      }
  }
  </code></pre>
  
  <p>My views are generally of the following form:</p>
  
  <pre><code>@model Foo.BarViewModel
  @{
      ViewBag.Title = "Application: " + Model.Name;
  }
  
  @Html.DisplayForModel()
  </code></pre>
  
  <p>Is it possible to read values in the ViewBag set in the view?</p>