title: EntityFramework Code First - Check if Entity is attached
body: <p>I am trying to update an entity with a FK relationship in EntityFramework 4.3 Code First.
  I try to attach to the related entites by calling: Entry(item).State = EntityState.Unchanged</p>
  
  <p>I get the following exception: <em>An object with the same key already exists in the ObjectStateManager. The ObjectStateManager cannot track multiple objects with the same key.</em></p>
  
  <p>I do not update these items nor have an id property for them on my main entity.
  Is it possible to know which entities are attached or not ?</p>
  
  <p>Thanks in advance,
  Radu</p>