具有多个字段的OrderByDescending

Question

我希望能够按d.DateUpdated排序，但只有当它不是DateTime.MinValue时才能排序。如果它是DateTime.MinValue，那么我需要它能够按d.DateCreated排序。有没有办法在下面的代码行中执行此操作？

return database.Table<Announcement>()
    .Where(i => i.GroupId == groupId)
    .OrderByDescending(d => d.DateUpdated)
    .ToListAsync();

Answer 1

您也可以使用ThenBy方法

return database.Table<Announcement>()
    .Where(i => i.GroupId == groupId)
    .OrderByDescending(d => d.DateUpdated)
    .ThenByDescending(d => d.DateCreated)
    .ToListAsync();

Answer 2

那样的东西？

return database.Table<Announcement>()
    .Where(i => i.GroupId == groupId)
    .OrderByDescending(d => d.DateUpdated == null ? d.DateCreated : d.DateUpdated)
    .ToListAsync();