NHibernate QueryOver restrict by string length

Question

How do I restrict a query by the length of a string property? eg. something like:

NHSession.QueryOver<Customer>()
    .Where(p => p.RegistryCode.Length == 8)

Answer 1

Something like this may do the trick

NHSession.QueryOver<Customer>()
    .Where(
        Restrictions.Eq(
            Projections.SqlFunction("length", NHibernateUtil.String, 
                Projections.Property<Customer>(x => x.RegistryCode)),
            8
        )
    )

Answer 2

Instead of "NHibernateUtil.String" i should use this "NHibernateUtil.Int16" type, because a 'length' parameter should always be a number and not a String.

Something like this:

NHSession.QueryOver<Customer>()
    .Where(
        Restrictions.Eq(
            Projections.SqlFunction("length", NHibernateUtil.Int16, 
                Projections.Property<Customer>(x => x.RegistryCode)),
            8
        )
    )