如何在 C# 中使用 mongodb 查询根据 CreatedUtc Date 对数据进行排序？

Question

我想根据 CreatedUtc 时间对数据进行排序。我曾尝试使用 Reverse 功能，它似乎可以解决，但仍在寻找一些替代选项。

var result = _participantRepo.AsQueryable().Where(x => x.Id == ParticipantId).SelectMany(x => 
    x.Relations).ToList().Where(x => x.UserId != AppUserId).Select(r => new RelationVM
                    {
                        IsOwner = r.UserId == participant.CreatedByUserId,
                        FirstName = r.FirstName,
                        LastName = r.LastName,
                        Email = r.Email,
                        UserId = r.UserId,
                        RelationType = r.RelationType,
                        Role = r.Role,
                        IsAccepted = r.IsAccepted,
                        AvatarUrl = r.AvatarUrl,
                        CreatedUtc = r.CreatedUtc
                    }).Reverse().ToList();

Answer 1

您需要关注两件事：

• 您可以使用OrderBy对序列的元素进行排序
• 你不应该在没有完成的时候.ToList()，所以你可以阅读LINQ deferred (or immediate?) execution有一个更好的理解。

因此，您的查询应如下所示

    var result = _participantRepo.AsQueryable().Where(x => x.Id == ParticipantId).SelectMany(x => 
        x.Relations).Where(x => x.UserId != AppUserId).Select(r => new RelationVM
                        {
                            IsOwner = r.UserId == participant.CreatedByUserId,
                            FirstName = r.FirstName,
                            LastName = r.LastName,
                            Email = r.Email,
                            UserId = r.UserId,
                            RelationType = r.RelationType,
                            Role = r.Role,
                            IsAccepted = r.IsAccepted,
                            AvatarUrl = r.AvatarUrl,
                            CreatedUtc = r.CreatedUtc
                        }).Reverse().OrderBy(g => g.CreatedUtc).ToList();

Answer 2

.OrderBy(g => g.CreatedUtc) 怎么样？