public IResponseMessage GetByPublishDate(string content)
 {
     var wxArticles = new List<ResponseMessageNews.Article>();
     using (var db = new WeChatDbContext())
     {
         var items = from item in db.Articles
                     where item.Published == content
                     orderby item.Published descending
                     select item;
         if (items.Count() == 0)
             return new ResponseMessageText("无此日期的文章,请尝试其他");
         foreach (var item in items)
         {
             var wxArticle = new ResponseMessageNews.Article
             {
                 Description = item.Description,
                 Title = item.Title,
                 PicUrl = new Uri(item.PicUrl),
                 Url = new Uri(item.Url)
             };
             wxArticles.Add(wxArticle);
         }
     }
     return new ResponseMessageNews(wxArticles.ToArray());
 }
 public IResponseMessage GetTop()
 {
     var wxArticles = new List<ResponseMessageNews.Article>();
     using (var db = new WeChatDbContext())
     {
         var items = from item in db.Articles
                     orderby item.Published descending
                     select item;
         foreach (var item in items.Take(5))
         {
             var wxArticle = new ResponseMessageNews.Article
             {
                 Description = item.Description,
                 Title = item.Title,
                 PicUrl = new Uri(item.PicUrl),
                 Url = new Uri(item.Url)
             };
             wxArticles.Add(wxArticle);
         }
     }
     return new ResponseMessageNews(wxArticles.ToArray());
 }
 internal IResponseMessage GetByTag(string content)
 {
     var wxArticles = new List<ResponseMessageNews.Article>();
     using (var db = new WeChatDbContext())
     {
         var items = from item in db.Articles
                     where item.Tags.Contains(content)
                     orderby item.Published descending
                     select item;
         if (items.Count() == 0)
             return null;
         foreach (var item in items.Take(10))
         {
             var wxArticle = new ResponseMessageNews.Article
             {
                 Description = item.Description,
                 Title = item.Title,
                 PicUrl = new Uri(item.PicUrl),
                 Url = new Uri(item.Url)
             };
             wxArticles.Add(wxArticle);
         }
     }
     return new ResponseMessageNews(wxArticles.ToArray());
 }