Question

这个linq为我提供了所有房间作为按rateCode分组的列表。

var results = (from r in dcCrs.CRS_RateTypePerReservation
                   where r.Reservation_id_fk == reservation.Reservation_id_pk 
                      && r.RoomTypeCenter_id_fk != null 
                      && r.Price != 0
               group r.RoomTypesPerCenter.RoomTypes.Code by r.CRS_RateTypes.Name into g
               select new { rateCode = g.Key, roomName = g.ToList() });

但是现在我必须通过数据库中的Integer对结果进行排序，命名为Order：

var results = (from r in dcCrs.CRS_RateTypePerReservation
                   where r.Reservation_id_fk == reservation.Reservation_id_pk 
                      && r.RoomTypeCenter_id_fk != null 
                      && r.Price != 0
                   orderby r.Order ascending
                   group r.RoomTypesPerCenter.RoomTypes.Code by r.CRS_RateTypes.Name into g
                   select new { rateCode = g.Key, roomName = g.ToList() });

这只订购房间的名称，而不是两者。

数据：

Order   Rates      RoomType 
5       PER        DBL  
30      PER        IND
15      BAR        IND
10      BAR        DBL  
20      BAR        URB

它应该给出这个结果，因为第一个是5和30（PER）然后是10,15和20（BAR）：

   {rateCode = PER, roomName = {DBL, IND} }

   {rateCode = BAR, roomName = {DBL, IND, URB} }

但它让我回答：

   {rateCode = BAR, roomName = {DBL, IND, URB} }

   {rateCode = PER, roomName = {DBL, IND} }

感谢您的任何建议。

Answer 1

数据库GROUP BY查询结果的键顺序未定义。

您需要在分组后应用排序，例如

var results = 
   (from r in dcCrs.CRS_RateTypePerReservation
    where r.Reservation_id_fk == reservation.Reservation_id_pk 
        && r.RoomTypeCenter_id_fk != null 
        && r.Price != 0
    group r by r.CRS_RateTypes.Name into g
    orderby g.Min(r => r.Order)
    select new
    {    
        rateCode = g.Key,
        roomName = (from r in g orderby r.Order select r.RoomTypesPerCenter.RoomTypes.Code).ToList()
    });

如何在Linq中使用列表订购组结果？

1 个答案: