title: Check if List contains an instance equal to a given one
body: <p>I don't want to loop through the list comparing each property. Something with this functionality:</p>
  
  <pre><code>class myClass
  {
      public int I { get; set; }
  }
  
  class Program
  {
      static void Main(string[] args)
      {
          List&lt;myClass&gt; l = new List&lt;myClass&gt;();
  
          myClass x = new myClass();
          x.I = 1;
          l.Add(x);
  
          myClass y = new myClass();
          y.I = 2;
          l.Add(y);
  
          myClass z = new myClass();
          z.I = 2;
  
          if (l.ContainsAnInstanceEqualTo(z))
              Console.WriteLine("Contains");
  
          Console.ReadLine();
      }
  }
  </code></pre>
  
  <p>IMPORTANT: I have no control over the class and there are a few properties which should have the same value.</p>