读取和修改xml

如有一个xml文件DownData.xml，内容如下

<?xml version="1.0" standalone="yes"?>
<Root>
  <Downloads>1339</Downloads>
  <Consumption>1223381</Consumption>
  <Rebate>207977.26</Rebate>
</Root>

读取数据
private void GetInfo()
        {
            DataSet ds = new DataSet();
            string strXmlPath = Server.MapPath("~/config/DownData.xml");//xml路径
            ds.ReadXml(strXmlPath);
            string downStr= ds.Tables[0].Rows[0]["Downloads"].ToString();
            string conStr=  ds.Tables[0].Rows[0]["Consumption"].ToString();
           string reStr=  ds.Tables[0].Rows[0]["Rebate"].ToString();
        }
修改数据

protected void Change()        

{            

            DataSet ds = new DataSet();       

            string strXmlPath = Server.MapPath("~/config/DownData.xml");

            ds.ReadXml(strXmlPath);            

            ds.Tables[0].Rows[0]["Downloads"] ="2000";            

            ds.Tables[0].Rows[0]["Consumption"] = "1000000";         

            ds.Tables[0].Rows[0]["Rebate"] = "122444";          

            ds.AcceptChanges();             //写入xml

            ds.WriteXml(strXmlPath);       

  }