Question

发布课程：

public class Post
{
    [BsonRepresentation(BsonType.ObjectId)]
    public string Id { get; set; } 
    [BsonRepresentation(BsonType.ObjectId)]
    public string CreatorId { get; set; }
    public string CreatorName { get; set; }
    public string Text { get; set; }
    public bool IsPublic { get; set; }
    public ICollection<Comment> Comments { get; set; }
    public DateTime CreationDate { get { return ObjectId.Parse(Id).CreationTime; } }
    public DateTime? DeletionDate { get; set; }
}

评论类：

public class Comment
{
    [BsonRepresentation(BsonType.ObjectId)]
    public string Id { get; set; }
    [BsonRepresentation(BsonType.ObjectId)]
    public string CreatorId { get; set; }
    public string CreatorName { get; set; }
    public string Text { get; set; }
    public DateTime CreationDate { get { return ObjectId.Parse(Id).CreationTime; } }
    public DateTime? DeletionDate { get; set; }
}

如果DeletionDate和Comment等于给定参数，我希望在Post.Comments内设置Comment.Id的{{1}}属性。

我该怎么做？

Answer 1

QueryDocument query= new QueryDocument();
            query.Add(new BsonDocument("Comments.$.Id","givenCommentId"));
            UpdateDocument update = new UpdateDocument();
            update.Add(new BsonElement("Comments.$.DeletionDate", "yourUpdatedDate"));

您可以在FindAndModifyArgs

中使用它

但是我忘记了位置运算符$是否可用于两个或多个字段，因此我不在查询中添加new BsonDocument("Comments.$.CreatorId","givenCommentCreatorId")。您需要对其进行测试。

Answer 2

我解决了以下问题：

var query = Query<Post>.ElemMatch(p => p.Comments, builder => 
    builder.And(
        Query<Comment>.EQ(c => c.Id, commentId),
        Query<Comment>.EQ(c => c.CreatorId, creatorId)));

var update = Update.Set("Comments.$.DeletionDate", DateTime.UtcNow);

var args = new FindAndModifyArgs
{
    Query = query,
    Update = update
};

var result = _db.Posts.FindAndModify(args);

使用FindAndModify更新特定集合项的属性

2 个答案: