Paul, a couple of questions:

1. Were you expecting PropertyChanged to fire on the parent when an internal change was made to one of the children, or when the list of children changed (by an addition or removal). It should not fire in the former case, but should in the latter. Did you find that it wasn't firing in the latter case?
   
   
2. I was able to get PropertyChanged to fire on an Order (parent) entity in response to an internal change made to one of the Order's OrderDetails(i.e., one of the parent's children). To do so, I implemented an AfterSet property interceptor as follows:

    [AfterSet(EntityPropertyNames.UnitPrice)]
    public void UnitPriceChanged(PropertyInterceptorArgs<Order, Decimal> args) {
      PropertyChangedEventArgs eventArgs = new PropertyChangedEventArgs("OrderDetails");
      this.Order.EntityAspect.ForcePropertyChanged(eventArgs);
    }

Is that what you are trying to do?

Note that, in instigating the raising of the PropertyChanged event on the parent, I indicated the parent's collection property (OrderDetails) as the property that changed, even though, strictly speaking, the list didn't change, only the internal details of one of its members.

Incidentally, I'm not obligated to indicate any particular property in my call to ForcePropertyChanged(). If I don't want to indicate a particular property, I can pass a null to the PropertyChangedEventArgs constructor.

Greg