title: ASP.NET MVC null model passed to controller action
body: <p>Why is a null parameter being passed to the following controller action?</p>
  
  <pre><code> public FileContentResult GetImageForArticle(ArticleSummary article) 
          {             
              if (article == null || !article.ContainsValidThumbNail()) return null;            
              return File(article.ThumbNail, article.ThumbNaiType);
          }  
  </code></pre>
  
  <p>from the following partial view:</p>
  
  <pre><code>&lt;%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl&lt;IEnumerable&lt;AkwiMemorial.Models.ArticleSummary&gt;&gt;" %&gt;
  &lt;%if (Model.Count() &gt; 0)
    { %&gt;
  &lt;table&gt;    
      &lt;% foreach (var item in Model)
         { %&gt;    
          &lt;tr&gt;                        
               &lt;td&gt;  
                 &lt;img src='&lt;%=Url.Action("GetImageForArticle", "Resources", new { article = item })%&gt;' alt=""/&gt;                                
              &lt;/td&gt;
          &lt;/tr&gt;
  
      &lt;% } %&gt;
  
      &lt;/table&gt;
  </code></pre>