title: Contains with Linq
body: <p>I have class "Estimation", this class has a property "EstimationItems" (the type  is IList)</p>
  
  <pre><code>public class EstimationItem 
  {
      public virtual int Id { get; set; }
      public virtual Product Product { get; set; }
      public virtual int Quantity { get; set; }
      public virtual decimal Price { get; set; }
  }
  
  public class Product 
  {
      public virtual int Id { get; set; }
      public virtual string Code { get; set; }
      public virtual string Name { get; set; }
  }
  </code></pre>
  
  <p>When I have an instance of "Estimation", I'd like to know if "EstimationItems" contain a product with the code "MyCode".</p>