/// <summary>
        /// 追加文章,如果 <see cref="Articles"/> 数量大于10则忽略。
        /// </summary>
        /// <param name="articles">文章数组。</param>
        public void Append(params Article[] articles)
        {
            if (articles.NotNull("articles").Length > ArticleMaxCount)
            {
                throw new ArgumentException(string.Format("文章数量不能大于 {0} 条。", ArticleMaxCount), "articles");
            }

            Articles = Articles == null ? articles : Articles.Concat(articles.Take(ArticleMaxCount - Articles.Length)).ToArray();
        }