private SomeDelegate _myEvent = delegate {};

    public event SomeDelegate MyEvent
    {

        add { _myEvent += value; }
        remove { _myEvent -= value; }

    }

    public event EventHandler MyEvent;
    // Inside the class, MyEvent is bound to a multicast delegate.
    // Outside the class, MyEvent is bound to an auto-generated add/remove mechanism.
    // So MyEvent can only be set to null or invoked from inside the class.