NHibernate 联合查询报错 could not resolve property

           lt = session.CreateCriteria(typeof(module1)
           .CreateAlias("module2, "ip")
           .Add(Restrictions.Eq("ip.ID,ObjectID))
           .List<module1>();

报错could not resolve property:
CreateAlias 使用就报错
CreateCriteria("")也会报错

求高人指教

参考：https://stackoverflow.com/questions/12930477/nhibernate-could-not-resolve-property