c# - 在 LINQ OrderBY 中排除一个值

Question

我有一个列表，我希望它按 DayOfWeek 排序，除了 DayOfWeek=1 的情况，它应该放在列表的末尾。我在 OrderBy 和 ThenBy 上尝试了一些变体，但它似乎继续按数字顺序排序。

我确信这很简单，我不想更改 Day=1 的值，这是原来的解决方案

var dayOfWeeksHolder = Enumerable.Range(1, 7);   
var defaultTime = DateTime.Today.TimeOfDay;
var psList = _pickingScheduleIO.GetDayScheduleList(branchNo);
var psListByType = psList.Where(p => p.PickingSesstionTypeId == pickingSessionTypeId).ToList();

var fullList = (from d in dayOfWeeksHolder
                join s in psListByType on d equals s.DayOfWeek into grp
                from ds in grp.DefaultIfEmpty()
                // where (ds == null || ds.PickingSesstionTypeId == pickingSessionTypeId)
                select new DayScheduleVM
                {
                    PickingScheduleId = ds == null ? 0 : ds.PickingSessionScheduleId,
                    DayOfWeek = d, //d == 1 ? d + 7 : d, //in sql sunday is 1, we need to make it to 8 so it will be sorted to last
                    StartTime = ds == null ? defaultTime : ds.StartTime,
                    EndTime = ds == null ? defaultTime : ds.EndTime,
                    PickingSessionTypeId = pickingSessionTypeId
                }).OrderBy(a => a.DayOfWeek !=1).ThenBy(a => a.DayOfWeek);
return fullList.ToList();

Answer 1

由于您使用的条件，您准确地得到了数字排序的印象a => a.DayOfWeek != 1。它将占用所有非星期日 ( true) 并将它们放在星期日 ( false) 之后，这就是对值进行OrderBy排序的方式boolean。

尝试：

• .OrderByDescending(a => a.DayofWeek != 1).ThenBy(a => a.DayofWeek)
• .OrderBy(a => a.DayofWeek == 1).ThenBy(a => a.DayofWeek)

Answer 2

尝试：

var fullList = (from d in dayOfWeeksHolder
                        join s in psListByType on d equals s.DayOfWeek into grp
                        from ds in grp.DefaultIfEmpty()
          //              where (ds == null || ds.PickingSesstionTypeId == pickingSessionTypeId)
                        select new DayScheduleVM
                        {
                            PickingScheduleId = ds == null ? 0 : ds.PickingSessionScheduleId,
                            DayOfWeek = d,//d == 1 ? d + 7 : d, //in sql sunday is 1, we need to make it to 8 so it will be sorted to last
                            StartTime = ds == null ? defaultTime : ds.StartTime,
                            EndTime = ds == null ? defaultTime : ds.EndTime,
                            PickingSessionTypeId = pickingSessionTypeId
                        });

return fullList.SkipWhile(a => a.DayOfWeek == 1).OrderBy(a => a.DayOfWeek).Concat(fullList.TakeWhile(a => a.DayOfWeek == 1));