C#操作XML的方法

添加命名空间：

using System.Xml;

 1，先创建一个BookModel类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace xmllianxi
{
    class BookModel
    {
        /// <summary>
        /// 所对应的课程类型
        /// </summary>
        private string bookType;
        public string BookType
        {
            get { return bookType; }
            set { bookType = value; }
        }
        /// <summary>
        /// 书所对应的ISBN号
        /// </summary>
        private string bookISBN;
        public string BookISBN
        {
            get { return bookISBN; }
            set { bookISBN = value; }
        }
        /// <summary>
        /// 书名
        /// </summary>
        private string bookName;
        public string BookName
        {
            get { return bookName; }
            set { bookName = value; }
        }
        /// <summary>
        /// 作者
        /// </summary>
        private string bookAuthor;
        public string BookAuthor
        {
            get { return bookAuthor; }
            set { bookAuthor = value; }
        }
        /// <summary>
        /// 价格
        /// </summary>
        private double bookPrice;
        public double BookPrice
        {
            get { return bookPrice; }
            set { bookPrice = value; }
        }
        /// <summary>
        /// flag
        /// </summary>
        private string bookFlag;
        public string BookFlag
        {
            get { return bookFlag; }
            set { bookFlag = value; }
        }
    }
}

 2，创建xml文件，及增删改查xml文件：

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

namespace xmllianxi
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button5_Click(object sender, EventArgs e)//创建xml
        {
            XmlDocument doc = new XmlDocument();
            //加入XML的声明段落,<?xml version="1.0" encoding="gb2312"?>
            XmlDeclaration xmldecl;
            xmldecl = doc.CreateXmlDeclaration("1.0", "utf-8", null);
            doc.AppendChild(xmldecl);
            //加入一个根元素
            XmlElement xe = doc.CreateElement("", "bookstore", "");
            doc.AppendChild(xe);

            //加入另外一个元素
            XmlNode xn1 = doc.SelectSingleNode("bookstore");//查找<bookstore> 
            XmlElement xel1 = doc.CreateElement("book");//创建一个<book>节点 
            xel1.SetAttribute("Type", "必修课");//设置该节点genre属性 
            xel1.SetAttribute("ISBN", "1-1");//设置该节点ISBN属性 
            //创建子结点
            XmlElement xelName1 = doc.CreateElement("title");
            xelName1.InnerText = "C#从入门到精通";
            XmlElement xelAuthor1 = doc.CreateElement("author");
            xelAuthor1.InnerText = "张三";
            XmlElement xelPrice1 = doc.CreateElement("price");
            xelPrice1.InnerText = "30";
            xel1.AppendChild(xelName1);
            xel1.AppendChild(xelAuthor1);
            xel1.AppendChild(xelPrice1);
            xn1.AppendChild(xel1);

            //加入另外一个元素
            XmlNode xn2 = doc.SelectSingleNode("bookstore");//查找<bookstore> 
            XmlElement xel2 = doc.CreateElement("book");//创建一个<book>节点 
            xel2.SetAttribute("Type", "必修课");//设置该节点genre属性 
            xel2.SetAttribute("ISBN", "1-2");//设置该节点ISBN属性 
            //创建子结点
            XmlElement xelName2 = doc.CreateElement("title");
            xelName2.InnerText = "C#基础";
            XmlElement xelAuthor2 = doc.CreateElement("author");
            xelAuthor2.InnerText = "李四";
            XmlElement xelPrice2 = doc.CreateElement("price");
            xelPrice2.InnerText = "20";
            xel2.AppendChild(xelName2);
            xel2.AppendChild(xelAuthor2);
            xel2.AppendChild(xelPrice2);
            xn2.AppendChild(xel2);

            //加入另外一个元素
            XmlNode xn3 = doc.SelectSingleNode("bookstore");//查找<bookstore> 
            XmlElement xel3 = doc.CreateElement("book");//创建一个<book>节点 
            xel3.SetAttribute("Type", "必修课");//设置该节点genre属性 
            xel3.SetAttribute("ISBN", "1-3");//设置该节点ISBN属性 
            //创建子结点
            XmlElement xelName3 = doc.CreateElement("title");
            xelName3.InnerText = "Unity3D基础";
            XmlElement xelAuthor3 = doc.CreateElement("author");
            xelAuthor3.InnerText = "王五";
            XmlElement xelPrice3 = doc.CreateElement("price");
            xelPrice3.InnerText = "45";
            xel3.AppendChild(xelName3);
            xel3.AppendChild(xelAuthor3);
            xel3.AppendChild(xelPrice3);
            xn3.AppendChild(xel3);

            //加入另外一个元素
            XmlNode xn4 = doc.SelectSingleNode("bookstore");//查找<bookstore> 
            XmlElement xel4 = doc.CreateElement("book");//创建一个<book>节点 
            xel4.SetAttribute("Type", "必修课");//设置该节点genre属性 
            xel4.SetAttribute("ISBN", "1-4");//设置该节点ISBN属性 
            //创建子结点
            XmlElement xelName4 = doc.CreateElement("title");
            xelName4.InnerText = "计算机基础";
            XmlElement xelAuthor4 = doc.CreateElement("author");
            xelAuthor4.InnerText = "赵六";
            XmlElement xelPrice4 = doc.CreateElement("price");
            xelPrice4.InnerText = "25";
            xel4.AppendChild(xelName4);
            xel4.AppendChild(xelAuthor4);
            xel4.AppendChild(xelPrice4);
            xn4.AppendChild(xel4);

            //保存创建好的XML文档
            doc.Save(@"Book.xml");
            Select();
        }

        public void Select()
        {
            //使用XmlDocument读取XML文件
            XmlDocument doc = new XmlDocument();
            doc.Load(@"Book.xml");
            XmlNode xn = doc.SelectSingleNode("bookstore");// 得到根节点bookstore      
            XmlNodeList nodelist = xn.ChildNodes;// 得到根节点的所有子节点
            List<BookModel> bookModeList = new List<BookModel>();
            foreach (XmlNode xn1 in nodelist)
            {
                BookModel bookModel = new BookModel();
                XmlElement xe = (XmlElement)xn1;// 将节点转换为元素，便于得到节点的属性值
                bookModel.BookType = xe.GetAttribute("Type").ToString();// 得到Type的属性值
                bookModel.BookISBN = xe.GetAttribute("ISBN").ToString();
                // 得到Book节点的所有子节点
                XmlNodeList xml = xe.ChildNodes;
                bookModel.BookName = xml.Item(0).InnerText;
                bookModel.BookAuthor = xml.Item(1).InnerText;
                bookModel.BookPrice = Convert.ToDouble(xml.Item(2).InnerText);

                if (xml.Item(3) != null)
                {
                    bookModel.BookFlag = xml.Item(3).InnerText;
                }

                bookModeList.Add(bookModel);
            }
            dataGridView1.DataSource = bookModeList;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Select();
        }

        private void button2_Click(object sender, EventArgs e)//增加
        {
            //加载文件并选出根结点
            XmlDocument doc = new XmlDocument();
            doc.Load(@"Book.xml");
            XmlNode xn = doc.SelectSingleNode("bookstore");

            //用上面的方法,是向已有的文件上追加数据,如果想覆盖原有的所有数据,使用LoadXml方法
            //直接把根结点选择出来了,后面不用SelectSingleNode方法选择根结点,直接创建结点即可
            //XmlDocument doc = new XmlDocument();
            //doc.LoadXml("<bookstore></bookstore>");//用这句话,会把以前的数据全部覆盖掉,只有你增加的数据

            XmlElement xel = doc.CreateElement("book");//创建一个book结点
            xel.SetAttribute("Type", "必修课");//设置节点属性
            xel.SetAttribute("ISBN", "1-10");
            //创建子结点
            XmlElement xelName = doc.CreateElement("title");
            xelName.InnerText = "数据库基础";
            XmlElement xelAuthor = doc.CreateElement("author");
            xelAuthor.InnerText = "李老头";
            XmlElement xelPrice = doc.CreateElement("price");
            xelPrice.InnerText = "28";
            xel.AppendChild(xelName);
            xel.AppendChild(xelAuthor);
            xel.AppendChild(xelPrice);
            //最后把book结点挂接在根结点上,并保存整个文件
            xn.AppendChild(xel);
            doc.Save(@"Book.xml");
            Select();
        }

        private void button3_Click(object sender, EventArgs e)//删除
        {
            XmlDocument doc = new XmlDocument();
            doc.Load(@"Book.xml");
            XmlNode xn = doc.SelectSingleNode("bookstore");// 得到根节点bookstore      
            XmlNodeList nodelist = xn.ChildNodes;// 得到根节点的所有子节点
            for (int i = 0; i < nodelist.Count; i++)
            {
                XmlElement xe = (XmlElement)nodelist.Item(i);
                if (xe.GetAttribute("ISBN") == "1-10")
                {
                    xn.RemoveChild(xe);
                    if (i < nodelist.Count)
                        i = i - 1;
                }
            }
            doc.Save(@"Book.xml");
            Select();
        }

        private void button4_Click(object sender, EventArgs e)//修改
        {
            XmlDocument doc = new XmlDocument();
            doc.Load(@"Book.xml");
            XmlNodeList nodeList = doc.SelectSingleNode("bookstore").ChildNodes;//获取根节点的所有子节点
            foreach (XmlNode xn in nodeList)//遍历所有子节点
            {
                XmlElement xe = (XmlElement)xn; //将子节点类型转换为XmlElement类型
                if (xe.GetAttribute("ISBN") == "1-4")
                {
                    xe.SetAttribute("ISBN", "update 1-4");
                    XmlNodeList xnls = xe.ChildNodes;//继续获取xe子节点的所有子节点
                    foreach (XmlNode xn1 in xnls)
                    {
                        XmlElement xe2 = (XmlElement)xn1;
                        if (xe2.Name == "author")
                        {
                            xe2.InnerText = "赵老头";
                            break;
                        }
                    }
                    break;
                }
            }
            doc.Save(@"Book.xml");
            Select();
        }

        private void button6_Click(object sender, EventArgs e)//添加一个子节点
        {
            XmlDocument doc = new XmlDocument();
            doc.Load(@"Book.xml");
            XmlNodeList nodeList = doc.SelectSingleNode("bookstore").ChildNodes;//获取根节点的所有子节点
            foreach (XmlNode xn in nodeList)//遍历所有子节点
            {
                XmlElement xe = (XmlElement)xn; //将子节点类型转换为XmlElement类型
                //创建子结点
                XmlElement xelFlag = doc.CreateElement("flag");
                xelFlag.InnerText = "11111";
                xe.AppendChild(xelFlag);
            }
            doc.Save(@"Book.xml");
            Select();
        }

        private void button7_Click(object sender, EventArgs e)//删除一个子节点
        {
            XmlDocument doc = new XmlDocument();
            doc.Load(@"Book.xml");
            XmlNodeList nodeList = doc.SelectSingleNode("bookstore").ChildNodes;//获取根节点的所有子节点
            foreach (XmlNode xn in nodeList)
            {
                XmlElement xe = (XmlElement)xn;
                XmlNodeList xnl = xe.ChildNodes;//获取xe子节点的所有子节点 
                foreach (XmlNode xn1 in xnl)//遍历 
                {
                    XmlElement xe2 = (XmlElement)xn1;//转换类型 
                    if (xe2.Name == "flag")//如果找到 
                    {
                        xe.RemoveChild(xe2);//则删除
                    }
                }
            }
            doc.Save(@"Book.xml");
            Select();
        }
    }
}