public void Undo()
        {
            MementoPost   save     = new MementoPost();
            PostCaretaker savelist = new PostCaretaker();

            save.RestoreMemento(savelist.Memento);
        }
        public Posts UpdatePost(Posts updatepost)
        {
            MementoPost   save     = new MementoPost();
            PostCaretaker savelist = new PostCaretaker();
            Posts         post     = postlist.FirstOrDefault(p => p.PostID == updatepost.pID);

            if (post != null)
            {
                save.UserTitleName = post.titleN = updatepost.UserTitleName;
                save.UserPost      = post.postN = updatepost.UserPost;
                save.UserComment   = post.commentN = updatepost.UserComment;
            }
            else
            {
                postlist.Where(p => p.PostID == updatepost.pID);
                Undo();
            }
            return(post);
        }