Why is my Entity Framework Code First proxy collection null and why can't I set it?

Question

I am using DBContext and have two classes whose properties are all virtual. I can see in the debugger that I am getting a proxy object when I query the context. However, a c

Answer 1

Old question...

Poco class:

public partial class MyPOCO
{
    public MyPOCO()
    {
        this.MyPocoSub = new HashSet();
    }

    //VIRTUAL
    public virtual ICollection MyPocoSub { get; set; }
}

and proxy code:

    public override ICollection MyPocoSubSets
    {
        get
        {
            ICollection myPocoSubSets = base.MyPocoSubSets;
            if (!this.ef_proxy_interceptorForMyPocoSubSets(this, myPocoSubSets))
            {
                return base.MyPocoSubSets;
            }
            return myPocoSubSets;
        }
        set
        {
            if (value != this.RelationshipManager.GetRelatedEnd("WindowsFormsApplication.Models.MyPocoSubSet_MyPOCO", "MyPocoSubSet_MyPOCO_Source"))
            {
                // EXCEPTION 
                throw new InvalidOperationException("The property 'MyPocoSubSets' on type 'MyPOCO_A78FCE6C6A890855C68B368B750864E3136B589F9023C7B1D90BF7C83FD291AC' cannot be set because the collection is already set to an EntityCollection.");
            }
            base.MyPocoSubSets = value;
        }
    }

As you can see that exception raised in proxy class in ExtityFramework 5. This means that behavior still exist.