Linq离开Join带来重复值

Question

我有两个表帖和评论，我使用左连接到帖子和评论表但我得到多个相同的值，如何我可以删除重复值

public dynamic getalldetails()
    {
    GetAllPost =(
        from user in dbContext.UserTable
        join post in dbContext.PostTable on user.userId equals  post.userID into PostGroup
            from postdetails in PostGroup.DefaultIfEmpty()
            join comment in dbContext.CommentTable on postdetails.PostId equals comment.PostedId into commentGroup
                from commentdetails in commentGroup.DefaultIfEmpty()
                orderby postdetails.CreatedAt descending
                select new                                  
                {
                    userID          = user              == null ? 0     : user.userId,
                    name            = user              == null ? " "   : user.Name,
                    postId          = postdetails       == null ? 0     : postdetails.postId
                    postedMessage   = postdetails       == null ? " "   : postdetails.postedMessage
                    commentId       = commentdetails    == null ? 0     : commentdetails.commentId
                    commentMessage  = commentdetails    == null ? " "   : commentdetails.commentMessage
                } 
        }
    ).AsEnumerable();
}

我很有价值      1个帖子1个评论             2评论

 1 post 1 comment
        2 comment

 2 post 1 comment
        2 comment

 2 post 1 comment
        2 comment

我需要它像

 1 post 1 comment
        2 comment
 2 post 1 comment
        2 comment