title: sortdir not working on enum data type in MVC 3 WebGird
body: <p>I have the following structure:</p>
  
  <p>Model</p>
  
  <pre><code>public class EventEntry : LogEntry
  {
      public EventType Type { get; set; }
  
      public string Source { get; set; }
  }
  
  public enum EventType : int
  {
      Information = 1,
      Warning = 2,
      Error = 3
  } 
  </code></pre>
  
  <p>View</p>
  
  <pre><code>&lt;div id="grid"&gt;
  @{
      var grid = new WebGrid(canPage: true, rowsPerPage: Ctrl.PageSize, canSort: true, ajaxUpdateContainerId: "grid");
      grid.Bind(Model.Events, rowCount: Model.TotalRecords, autoSortAndPage: false);
  
      grid.Pager(WebGridPagerModes.All);
      @grid.GetHtml(htmlAttributes: new { id="grid" },
              columns: grid.Columns(
              grid.Column("Type"),
              grid.Column("Source"));    
  }
  &lt;/div&gt;
  </code></pre>
  
  <p>Controller</p>
  
  <pre><code>public ActionResult Index(int? page, string sort, string sortdir) {...}
  </code></pre>
  
  <p>When I click on "Source" column that is of type string, the sordir will change from "ASC" to "DESC" but when I try the same thing on the "Type" column sordir will always return "ASC".</p>