title: Return first item in list if FirstOrDefault returns null
body: <p>I've got a <code>List</code> of products, I need to get the item from the list with a specific product <code>Id</code> that I get from a querystring parameter. However, I may not always have a product <code>Id</code> passed to me. If I don't have a product <code>Id</code>, I need to default to the first product in the list.</p>
  
  <p>At the moment I have:</p>
  
  <pre><code>@Model.Products.FirstOrDefault(x =&gt; x.Id == productId);
  </code></pre>
  
  <p>This just selects the product with that specific <code>Id</code>, if there isn't one, it will default to <code>null</code>.</p>
  
  <p>Is there a way to achieve what I want?</p>