XDocument 分页

初试用XDocument来分页，代码如下，用在WebService里面，但框架需要4.0以上，用来读取XML，拼接成Json

    private string FilterJSON(string str)
    {
        return str.Replace("'", "%27").Replace("\"", "%22");
    }
    [WebMethod]
    public string GetPageNews(string pageNum, string pageRowCount)
    {
        int nPageNum = 0;
        int nPageRowCount = 0;
        if (!int.TryParse(pageNum, out nPageNum) || !int.TryParse(pageRowCount, out nPageRowCount))
        {
            return string.Empty;
        }
        XDocument doc = XDocument.Load(@"D:\Test\News.xml");
        var data = from d in doc.Descendants("News")
                   select d;
        var subData = data.Skip((nPageNum - 1) * nPageRowCount).Take(nPageRowCount);  // Paging.  
        StringBuilder sb = new StringBuilder();
        sb.Append("[");
        string strID = string.Empty;
        string strTitle = string.Empty;
        string strSummary = string.Empty;
        string strImageURL = string.Empty;
        string strDate = string.Empty;
        IEnumerable<XElement> dnas;
        #region 遍历
        foreach (var q in subData)
        {
            dnas = from node in q.Descendants() select node;
            foreach (XElement node in dnas)
            {
                switch (node.Name.LocalName)
                {
                    case "ID":
                        strID = node.Value;
                        break;
                    case "Title":
                        strTitle = node.Value;
                        break;
                    case "ImageURL":
                        strImageURL = node.Value;
                        break;
                    case "Summary":
                        strSummary = node.Value;
                        break;
                    case "Date":
                        strDate = node.Value;
                        break;
                    default:
                        break;
                }
            }
            sb.AppendFormat("{{\"ID\":\"{0}\",\"标题\":\"{1}\",\"摘要\":\"{2}\",\"图片地址\":\"{3}\",\"发布日期\":\"{4}\"}}",
          strID, FilterJSON(strTitle), FilterJSON(strSummary), strImageURL, strDate);
            sb.Append(",");
        }
        return sb.ToString().Trim(',') + "]";
        #endregion
    }
    [WebMethod]
    public string GetNewsDetail(string id)
    {

        XDocument doc = XDocument.Load(@"D:\TestNews.xml");
        var data = from d in doc.Root.Descendants("News")
                   where d.Element("ID").Value == id.ToString()
                   select d;
        var subData = data.Take(1);
        StringBuilder sb = new StringBuilder();
        string strID = string.Empty;
        string strTitle = string.Empty;
        string strSource = string.Empty;//来源
        string strBody = string.Empty;//正文
        string strBImageURL = string.Empty;//大图地址
        string strSImageURL = string.Empty;//小图地址
        string strDate = string.Empty;
        IEnumerable<XElement> dnas;
        //Console.WriteLine("count:" + subData.Count());
        #region 遍历
        foreach (var q in subData)
        {
            dnas = from node in q.Descendants() select node;
            foreach (XElement node in dnas)
            {
                switch (node.Name.LocalName)
                {
                    case "ID":
                        strID = node.Value;
                        break;
                    case "Title":
                        strTitle = node.Value;
                        break;
                    case "Source":
                        strSource = node.Value;
                        break;
                    case "Body":
                        strBody = node.Value;
                        break;
                    case "BImageURL":
                        strBImageURL = node.Value;
                        break;
                    case "SImageURL":
                        strSImageURL = node.Value;
                        break;
                    case "Date":
                        strDate = node.Value;
                        break;
                    default:
                        break;
                }
            }
            sb.AppendFormat("{{\"ID\":\"{0}\",\"标题\":\"{1}\",\"发布时间\":\"{2}\",\"来源\":\"{3}\",\"正文\":\"{4}\",\"小图地址\":\"{5}\",\"大图地址\":\"{6}\"}}",
          strID, FilterJSON(strTitle), strDate, FilterJSON(strSource), FilterJSON(strBody), strSImageURL, strBImageURL);
        }
        #endregion
        return sb.ToString();
    }
    [WebMethod]