NHibernate Linq扩展命令子对象集合

Question

I'm trying to query my db with NH Linq extensions and here is where I am stuck:

I have a Customer object and it has a property of type Order , and Order has an ICollection<Orderline> collection, and lastly Orderline object has a property of type int called ' price '. What I want to do is, given a customerId, I should get all customer information(Order and Orderline) and the collection of Orderline objects should be ordered by Orderline's price property. I've left out all other details for clarity.

Note: In this case the relation between Customer and Order is 1 to 1 . A customer can have only 1 order, an Order may contain many Orderlines as you may infer from the collection type.

Many thanks for any help...

Answer 1

var query = from customer in session.Query<Customer>()
            let order = customer.Order
            from orderline in order.Orderlines
            orderby orderlines.price
            select new
            {
                CustomerId = customer.Id,
                CustomerName = customer.Name,
                OrderId = order.Id,
                OrderLineId = orderline.Id,
                Price = orderline.Price,
            };

var results = query.ToLookup(a => a.CustomerId)
    .Select(g => new CustomerDto
    {
        Id = g.Key,
        CustomerName = g.First().CustomerName,
        OrderLines =  g.Select(a => new OrderLineDto(a.OrderLineId, a.Price)).ToList()
    }).ToList();