XML的操作

//增加新会员 0表成功，-1表已存在同名会员
userlist.xml的XML文档，其格式如下：

<?xml version="1.0" encoding="utf-8" ?>

<userlist>

       <user>

          <id>Samuel</id>

          <pass>111</pass>

    <nickname>Samuel</nickname>

    <tel>123456789</tel>

          <email>email@email.com</email>

          <address>重庆大学</address>

      </user>

        </userlist>

UserList类将用DOM访问userlist.xml文档(关于DOM,请参阅第三章)，并向外提供以下方法：

1). UserVerify方法，用于会员验证。

2). UserAdd方法，用于注册新会员。

3). UserDelete方法，用于删除会员。

4). UserChangePass方法，用于修改单个会员的密码。

在Solution Explorer中右击UserMan工程àAddàAdd New ItemàClass，取名UserList.cs，打开。UserList.cs的代码如下：

using System;

using System.Xml;

namespace UserMan{

         public class UserList{

                public UserList(){

             //构造函数

                }

          //会员登录 返回0表成功, -1表会员不存在 –2表密码错

               public int UserVerify( string sID, string sPass ){

                     XmlDocument doc = new XmlDocument();

                     XmlNode node;

                     XmlElement rootNode;

                     string sSelect;

                    

                     doc.Load("c://InetPub//wwwroot//UserMan//userlist.xml"); //装入XML文档

                     rootNode = doc.DocumentElement;    //rootNode指向userlist根结点

            sSelect = "descendant::user[id = '" + sID + "' ]";

            //node指向ID = sID的user结点

                     node= rootNode.SelectSingleNode(sSelect);

                     if (node == null)  

                            return -1;      //没找到，说明会员不存在

                     node = node.ChildNodes[1].ChildNodes[0];

                    //node指向该user结点的pass结点的文本结点

                     if ( node.Value != sPass )

                            return -2;     //密码错

                  return 0;         //登录成功

                }

                public int UserAdd(string sID, string sPass, string sNickname, string sTel,

string sEmail, string sAddress){

                     XmlDocument doc = new XmlDocument();

                     XmlNode node;

                     XmlElement rootNode;

                     string sSelect;

                    

                     doc.Load("c://InetPub//wwwroot//UserMan//userlist.xml");

                     rootNode = doc.DocumentElement;

                     sSelect = "descendant::user[id = '" + sID + "' ]";

                     node= rootNode.SelectSingleNode(sSelect);

                     if (node != null)

                            return -1;      //已存在同名会员

                     XmlElement elem = doc.CreateElement( "user" ); //新建一个user元素

                    //注意标记后的空格

                     string sXml = "<id>" + sID + "</id>  " + "<pass>" + sPass + "</pass>  " +

"<nickname>" + sNickname + "</nickname>  "                      + "<tel>" + sTel + "</tel>  " + "<email>" + sEmail +

"</email>  " + "<address>" + sAddress + "</address>  ";

             

                     elem.InnerXml = sXml;  //设定该user元素的内容

                     rootNode.AppendChild( elem );   //将新加的user元素作为根结点的子结点

                     doc.Save( "c://InetPub//wwwroot//UserMan//userlist.xml" );  //存盘

                     return 0;

                }

                //删除会员   0表成功，-1表会员不存在 –2表密码错

public int UserDelete( string sID, string sPass){

                     XmlDocument doc = new XmlDocument();

                     XmlNode node, nodeDelete;

                     XmlElement rootNode;

                     string sSelect;

                     doc.Load("c://InetPub//wwwroot//UserMan//userlist.xml");

                     rootNode = doc.DocumentElement;

                     sSelect = "descendant::user[id = '" + sID + "' ]";

            //nodeDelete指向准备删除的结点

                     nodeDelete = node = rootNode.SelectSingleNode(sSelect);

                     if (node == null)

                            return -1;      //返回会员不存在错误

                     node = node.ChildNodes[1];

                     if ( node.InnerText != sPass )

                            return -2;     //密码错

                     rootNode.RemoveChild( nodeDelete );   //删除该user结点

                     doc.Save( "c://InetPub//wwwroot//UserMan//userlist.xml" ); //存盘

                     return 0;

                }

//---------------------------------------------------------------------

//修改密码   0表成功 –1表会员不存在 –2表密码错
                public int UserChangePass( string sID, string sOldPass, string sNewPass ){

                     XmlDocument doc = new XmlDocument();

                     XmlNode node;

                     XmlElement rootNode;

                     string sSelect;

                    

                     doc.Load("c://InetPub//wwwroot//UserMan//userlist.xml");

                     rootNode = doc.DocumentElement;

                     sSelect = "descendant::user[id = '" + sID + "' ]";

                     node= rootNode.SelectSingleNode(sSelect);

                     if (node == null)

                            return -1;      //返回会员不存在错误

                     node = node.ChildNodes[1];

                     if ( node.InnerText != sOldPass )

                            return -2;     //密码错

            node.InnerText = sNewPass;       //修改密码

                     doc.Save( "c://InetPub//wwwroot//UserMan//userlist.xml" );  //存盘

                     return 0;

                }

           }

}