nhibernate mapping: A collection with cascade=“all-delete-orphan” was no longer referenced

Question

I am having some probs with my fluent mappings. I have an entity with a child collection of entities i.e Event and EventItems for example.

If I set my cascade mappin

Answer 1

You need to map _EventItems using an access strategy so that NHibernate access the private member instead of the property. You're getting this error because the collection reference is changed when the list is copied to a new List in _EventItems.ToList(). Try this:

public class EventMap : ClassMap
{
    public EventMap()
    {
        Id(x => x.Id, "Id")
            .UnsavedValue("00000000-0000-0000-0000-000000000000")
            .GeneratedBy.GuidComb();

        Map(x => x.Name);
        HasMany(x => x.EventItems)
            .Access.PascalCaseField(Prefix.Underscore)
            .Inverse()
            .KeyColumn("EventId")
            .AsBag()
            .Cascade.AllDeleteOrphan();
        }
    }
}