xml节点的添加和删除

添加之前的结果



添加之后的结果

删除之后就和添加之前是一样的了，呵呵

代码如下：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Xml;
using System.Windows.Forms;

namespace WindowsApp
{
    public partial class XMLForm2 : Form
    {
        private string _xmlstring=@"<blockList version='1'>
  <disk id='disk001'/>
  <disk id='disk002'/>
 </blockList>";

        public XMLForm2()
        {
            InitializeComponent();
        }
        private void display(string xml)
        {
            richTextBox1.Clear();
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.LoadXml(xml);
            _xmlstring = xmlDoc.OuterXml;
            XmlNodeList nodes = xmlDoc.SelectNodes("blockList/disk");
            foreach (XmlNode node in nodes)
            {
                richTextBox1.AppendText(node.Attributes["id"].Value);
                richTextBox1.AppendText(Environment.NewLine);
            }
        }
        /// <summary>
        /// 更新安全策略，产生新的阻断列表
        /// </summary>
        /// <param name="kbid">U盘金邦ID</param>
        /// <param name="flag">产生标志：1添加一个U盘，2删除一个U盘</param>
        public void Update(string kbid, int flag,ref string blockList)
        {
            
            switch (flag)
            {
                case 1:

                    insertDisk(kbid,ref blockList);
                    break;
                case 2:

                    deleteDisk(kbid,ref blockList);
                    break;
            }
            
        }
        /// <summary>
        /// 添加一个U盘到阻断列表
        /// </summary>
        /// <param name="kbid">U盘金邦ID</param>
        /// <param name="blockList">阻断列表</param>
        private void insertDisk(string kbid,ref string blockList)
        {
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.LoadXml(blockList);
            if (!contains(kbid, xmlDoc))
            {
                XmlNode root = xmlDoc.SelectSingleNode("/blockList");
                XmlElement node = xmlDoc.CreateElement("disk");
                node.SetAttribute("id", kbid);
                root.AppendChild(node);
                blockList = xmlDoc.OuterXml;
            }
        }
        /// <summary>
        /// 从阻断列表中删除一个U盘
        /// </summary>
        /// <param name="kbid">U盘金邦ID</param>
        /// <param name="blockList">阻断列表</param>
        private void deleteDisk(string kbid,ref string blockList)
        {
            XmlDocument xmlDoc = new XmlDocument();
            System.IO.StringWriter sw = new System.IO.StringWriter();
            xmlDoc.LoadXml(blockList);
            if (contains(kbid, xmlDoc))
            {
                XmlNode disk = xmlDoc.SelectSingleNode("/blockList/disk[@id='" + kbid + "']");
                XmlNode root = xmlDoc.SelectSingleNode("/blockList");
                root.RemoveChild(disk);
                xmlDoc.Save(sw);
                blockList = sw.ToString();
            }
        }
        /// <summary>
        /// 判断阻断列表中是否存在指定U盘
        /// </summary>
        /// <param name="kbid">U盘金邦ID</param>
        /// <param name="blockList">阻断列表</param>
        /// <returns></returns>
        private bool contains(string kbid, XmlDocument blockList)
        {
            XmlNode disk = blockList.SelectSingleNode("/blockList/disk[@id='"+kbid+"']");
            if (disk == null)
                return false;
            else
                return true;
        }

        private void XMLForm2_Load(object sender, EventArgs e)
        {
            display(_xmlstring);
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.Update("kb999", 1, ref _xmlstring);
            display(_xmlstring);
        }

        private void button2_Click(object sender, EventArgs e)
        {
            this.Update("kb999", 2, ref _xmlstring);
            display(_xmlstring);
        }
    }
}