title: ObservableCollection: how to use the FirstOrDefault?
body: <p>I have a custom class, with a property ID. We can name this class A, and the property ID.</p>
  
  <p>I have an observable collection of A, and I would like to get the firstOrDefault to know if an object exists with a determined ID. Soy I do the following:</p>
  
  <p>myObersableCollection.FirstOrDefault(a=>a.ID==2)</p>
  
  <p>But I get the following error: it is not possible to convert implicitly A into bool.</p>
  
  <p>What am I doing wrong?</p>
  
  <p>Thanks.
  Daimroc.</p>