title: IQueryable where clause
body: <p>Was difficult for me to find a fitting title for this post. But I have the following:</p>
  
  <pre><code>IArticleRepository articleRepo = unitOfWork.ArticleRepository;
  List&lt;Article&gt; articles = new List&lt;Article&gt;(
                           articleRepo.GetAll()
                           .Where(a =&gt; a.Title == searchTerm)
                           //.Where(a =&gt; a.Categories.Contains(Category.))
                           .OrderByDescending(a =&gt; a.CreatedDate));  
  </code></pre>
  
  <p>So some explanation: An <code>article</code> has , among other things, a <code>Title</code> and a <code>CreateDate</code>, and filtering through those is easy. But an <code>article</code> also has <code>categories</code> associated with it. So an <code>article</code> has an <code>array</code> property of type <code>Category</code>. Type <code>Category</code> has a property called <code>CategoryId</code> of type <code>int</code>.</p>
  
  <p>So in my code where it's commented out, I'm trying to <code>select</code> an <code>article</code>, which has a <code>category</code> associated with it, who's <code>CategoryId</code> is equal to.. say <code>4</code>.</p>
  
  <p>But I'm finding it quite difficult to express this in my C# syntax. I'm also new to C# so that's not helping either.</p>