linq to nhibernate:选择在一对多关联中具有特定实体的实体

我不确定这是否适用于您的特定情况,但我会使用 .Any() 扩展以稍微清除LINQ查询;例如:

Session.Linq<User>().Where(u => u.Payments.Any(p => p.Date != null));

我想是这样的:

Customer customerAlias = null; 
criteria = CurrentSession.CreateCriteria(typeof(User), () => customerAlias);
if (searchCriteria.OrdersNumber.HasValue)
{
     ICriteria paymentsCriteria = criteria.CreateCriteria<Customer>(x => x.Payments);

     DetachedCriteria paymentsCount = DetachedCriteria.For<Payment>();
     paymentsCount.SetProjection(Projections.RowCount());
     paymentsCount.Add(SqlExpression.NotNull<Payment>(x => x.Date));
     paymentsCount.Add<Payment>(x => x.Customer.Id == customerAlias.Id);

     paymentsCriteria.Add(Subqueries.Gt(1, paymentsCount));
 }

 return criteria.List<User>();