Update: I have fixed this issue
I have the following block of code which should ultimately update a record
The given key was not present in the dictionary.
System.Collections.Generic.KeyNotFoundException : The given key was not present in the dictionary.
at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
at NHibernate.Engine.StatefulPersistenceContext.RemoveEntity(EntityKey key)
at NHibernate.Event.Default.DefaultEvictEventListener.OnEvict(EvictEvent event)
at NHibernate.Impl.SessionImpl.FireEvict(EvictEvent evictEvent)
at NHibernate.Impl.SessionImpl.Evict(Object obj)
at Core.Repository.NHibernate.Repository.NoIdRepository`1.Update(T entity) in NoIdRepository.cs: line 26
at Core.Tests.Repository.NHibernate.Repository.TestInstanceVersionRepository.Test_Saving_Data() in TestInstanceVersionRepository.cs: line 63
It turns out that the Equals() method was comparing incorrectly, it was checking the equality of an additional property on the object which was not part of the composite key.
return obj != null && obj is InstanceVersion && this.Instance.Id == ((InstanceVersion)obj).Instance.Id && this.Version == ((InstanceVersion)obj).Version && this.DefaultEntry == ((InstanceVersion)obj).DefaultEntry;
Where DefaultEntry is a property .