Question

simple question for real gurus.
I lost a lot of time figuring how to map collection in nhib. mapping by code and I now I have question, why my mapping work with collection of type IList and not with List?

Here’s the code

public class Account {
    private IList<Term> Terms; // When I use List it does not work
    public Account()
    {
       Terms = new List<Terms>(); 
    }
    public virtual IList<Term> Terms // When I use List it does not work
    {
       get { return _Terms; }
       set 
       { if (_Terms == value) return;
           _Terms = value;
       }
    }
}

AccountMap.cs (One account have many terms)

Bag(x => x.Terms,
         m =>{},
         x => x.OneToMany()
);

Answer 1

Documentation says: 6.1. Persistent Collections:

NHibernate requires that persistent collection-valued fields be
declared as an interface type

And the list of supported interfaces:

The actual interface might be Iesi.Collections.ISet,
System.Collections.ICollection, System.Collections.IList,
System.Collections.IDictionary,
System.Collections.Generic.ICollection<T>,
System.Collections.Generic.IList<T>,
System.Collections.Generic.IDictionary<K, V>,
Iesi.Collections.Generic.ISet<T>

or … anything you like! (Where “anything you like” means you will have to write an implementation of NHibernate.UserType.IUserCollectionType.)