Question

如何从linq中的“group ... by ... into ...”语句中订购结果？例如：

var queryResult = from records in container.tableWhatever
                  where records.Time >= DateTime.Today
                  group records by tableWhatever.tableHeader.UserId into userRecords
                  select new { UserID = userRecords.Key, Records = userRecords };

查询返回按“UserId”分组的表“contains.tableWhatever”中的记录。我希望每个组中的返回结果按时间降序排序。我怎么能这样做？

更具体地说，假设上面的查询只返回一个如下所示的组：

{UserID = 1, Records= {name1 5/3/2010_7:10pm;
                       name2 5/3/2010_8:10pm;
                       name3 5/3/2010_9:10pm} }

在上面的查询中插入orderby语句后，返回的结果应如下所示：

{UserID = 1, Records= {name3 5/3/2010_9:10pm;
                       name2 5/3/2010_8:10pm;
                       name1 5/3/2010_7:10pm} }

感谢您的帮助！

Answer 1

只需使用OrderByDescending扩展程序对匿名类型的记录进行排序。

var queryResult = from records in container.tableWhatever 
                  where records.Time >= DateTime.Today 
                  group records by tableWhatever.tableHeader.UserId into userRecords 
                  select new
                  {
                       UserID = userRecords.Key,
                       Records = userRecords.OrderByDescending( u => u.Time )
                  };

Answer 2

你能做到：

var queryResult = from records in container.tableWhatever
              where records.Time >= DateTime.Today
              group records by tableWhatever.tableHeader.UserId into userRecords
              select new { UserID = userRecords.Key, Records = userRecords.OrderByDescending(r=>r.Time) };

如何使用Linq订购组结果？

2 个答案: