linq-to-nhibernate

If I had an Object A that contained a many-to-one reference to Object B, where Object B contained a one-to-many collection of Object C... consider the following query: IQueryable<A> query = getIQueryableSomehow(); List<B> resultList = query.Where(A => A.whatever == something).Select(A => A.B).Fetch(B => B.C).ToList(); I want to do something similar to this, but I keep getting a null reference exception with this code. Is there a sneaky trick to achieve this kind of query AND fetch a bunch of Object B collections, or is it impossible? Thanks! you can specify Fetch before to load all A,B,C and

I have classes BidiParent and BidiChildList which link parents and children in a bidirectional parent-child relationship. If a child's parent is updated by e.g. the service layer, the old and new parents' children lists are automatically updated to reflect the change. Likewise, if a parent's children list is updated by e.g. adding a new child, the child's parent is automatically changed as is the old parent's children list. I want to try to build up a "smart" domain model. First question, obviously, is: is this even a good idea? Second question is: is it possible to tell NHibernate to access