ASP.net在gridview中删除数据时同时更新xml文件

为了减少对数据库的访问,前台页面通常只对xml文件进行读取,但是更新数据库的时候需要同时更新xml文件,添加好办,但是删除的时候呢,下面的程序在gridview中删除数据的同时删除xml文件中对应的节点.xml文件的每个节点是一个图片新闻,包括图片和新闻页面的本地存储路径.

using system;
using system.collections;
using system.componentmodel;
using system.data;
using system.drawing;
using system.web;
using system.web.sessionstate;
using system.web.ui;
using system.web.ui.webcontrols;
using system.web.ui.htmlcontrols;
using system.data.sqlclient;
using system.xml;
using system.io;
using system.text;
using system.configuration;

/**//// <summary>
/// pic_manage 的摘要说明
/// </summary>
public partial class pic_manage : system.web.ui.page
...{
    public  pic_manage()
    ...{
        //
        // todo: 在此处添加构造函数逻辑
        //
    }
    protected void page_load(object sender, eventargs e)
    ...{
        if (session["user"] == null || "admin" != (string)(session["user"]))
        ...{
            response.redirect("login.aspx");
            return;
        }
    }
    protected void gridview1_rowdeleting(object sender, gridviewdeleteeventargs e)
    ...{
        int  key =convert.toint32( e.keys[0].tostring());
        sqlconnection conn = new sqlconnection();
        conn.connectionstring = configurationmanager.connectionstrings["ahpcconnectionstring"].connectionstring;
        string strsql = "select url from [news] where news_id="+key;
        sqldataadapter da = new sqldataadapter(strsql, conn);
        dataset ds = new dataset();
        da.fill(ds, "news");
        string url = ds.tables[0].rows[0].itemarray[0].tostring();
        conn.close();
       
        url = url.split(new char[] ...{ '|' })[0];
        string xmlpath = server.mappath("~/news/pic_news_list.xml");
        xmldocument doc = new xmldocument();
        doc.load(xmlpath);
        xmlelement root = doc.documentelement;
        xmlnodelist xnl = doc.selectsinglenode("ahpc").childnodes;

        foreach (xmlnode xn in xnl)
        ...{

            xmlelement xe = (xmlelement)xn;
               if (xe.firstchild.lastchild.innertext==url)       //因为在xml文件中只有url是各不相同的
            ...{

                //删除该图片新闻中的所有图片
                int count = xe.childnodes.count;
                for (int i = 0; i < count - 3; i++)
                ...{  
                    string delfile = "~/"+xe.childnodes[i].childnodes[1].innertext;
                    deletefile(delfile);
                }

                    root.removechild(xe);//删除该节点的全部内容

            }

        }

        doc.save(xmlpath);

       //删除图片新闻网页文件
        deletefile("~/news/picfile/" + url);

    }

    //删除文件函数
    public void deletefile(string filepathname)
    ...{
        try
        ...{
            fileinfo delefile = new fileinfo(system.web.httpcontext.current.server.mappath(filepathname).tostring());
            delefile.delete();
        }
        catch
        ...{
        }
    }

<?xml version="1.0" encoding="gb2312"?>
<ahpc>
       <news>
    <pic>
      <title>3333</title>
      <localurl>news/picfile/200704272014550.jpg</localurl>
      <url>20070427201455.htm</url>
    </pic>
    <title>33333333333</title>
    <abstract>《计算机组成原理及系统结构》课程设计指导书
      课程编号：
课程名称（中文/英文）：
计算机组成原理及系统结构/computer organization and architectur……</abstract>
    <time>2007-4-27 20:14:55</time>
  </news>
  <news>
    <pic>
      <title>3333333333</title>
      <localurl>news/picfile/200704272041170.jpg</localurl>
      <url>20070427204117.htm</url>
    </pic>
    <pic>
      <title>3333333333333333</title>
      <localurl>news/picfile/200704272041171.jpg</localurl>
      <url>20070427204117.htm</url>
    </pic>
    <title>44444444444444444444444444</title>
    <abstract>三大大的三大幅阿三多发洒的发洒的发洒的……</abstract>
    <time>2007-4-27 20:41:17</time>
  </news>
  <news>
    <pic>
      <title>22</title>
      <localurl>news/picfile/200704281419150.jpg</localurl>
      <url>20070428141915.htm</url>
    </pic>
    <title>333</title>
    <abstract>3333333……</abstract>
    <time>2007-4-28 14:19:15</time>
  </news>
  <news>
    <pic>
      <title>222</title>
      <localurl>news/picfile/200704281520320.gif</localurl>
      <url>20070428152032.htm</url>
    </pic>
    <title>333</title>
    <abstract>33333333333333……</abstract>
    <time>2007-4-28 15:20:32</time>
  </news>
</ahpc>