使用XmlDocument创建XML文档及增加删除更新节点

using System;
using System.Windows.Forms;
using System.Xml;

namespace XMLDemo
{
    public partial class FrmDOM : Form
    {
        public FrmDOM()
        {
            InitializeComponent();
        }

        private void btnLoad_Click(object sender, EventArgs e)
        {
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load("Books.xml");
            MessageBox.Show(xmlDoc.InnerXml);
        }

        private void btnCreate_Click(object sender, EventArgs e)
        {
            //xml文档
            XmlDocument xmlDoc = new XmlDocument();
            XmlDeclaration dec = xmlDoc.CreateXmlDeclaration("1.0", "utf-8", null);
            xmlDoc.AppendChild(dec);

            //创建根节点 
            XmlElement root = xmlDoc.CreateElement("Books");
            xmlDoc.AppendChild(root);

            //节点及元素
            XmlNode book = xmlDoc.CreateElement("Book");
            XmlElement title = GetXmlElement(xmlDoc, "Title", "Window Form");
            XmlElement isbn = GetXmlElement(xmlDoc, "ISBN", "111111");
            XmlElement author = GetXmlElement(xmlDoc, "Author", "amandag");
            XmlElement price = GetXmlElement(xmlDoc, "Price", "128.00");
            price.SetAttribute("Unit", "￥");

            book.AppendChild(title);
            book.AppendChild(isbn);
            book.AppendChild(author);
            book.AppendChild(price);
            root.AppendChild(book);

            xmlDoc.Save("Books.xml");
            MessageBox.Show("数据已写入！");
        }

        private void btnInsert_Click(object sender, EventArgs e)
        {
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load("Books.xml");

            XmlNode root = xmlDoc.SelectSingleNode("Books");

            XmlElement book = xmlDoc.CreateElement("Book");
            XmlElement title = GetXmlElement(xmlDoc, "Title", "ASP.NET");
            XmlElement isbn = GetXmlElement(xmlDoc, "ISBN", "222222");
            XmlElement author = GetXmlElement(xmlDoc, "Author", "moon");
            XmlElement price = GetXmlElement(xmlDoc, "Price", "111.00");
            price.SetAttribute("Unit", "{1}quot;);

            book.AppendChild(title);
            book.AppendChild(isbn);
            book.AppendChild(author);
            book.AppendChild(price);
            root.AppendChild(book);

            xmlDoc.Save("Books.xml");
            MessageBox.Show("数据已插入！");
        }

        private void btnUpdate_Click(object sender, EventArgs e)
        {
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load("Books.xml");

            //方法1:获取Books//Book节点的第一个子节点 
            XmlNodeList nodeList = xmlDoc.SelectSingleNode("Books//Book").ChildNodes;
            XmlElement xe = null;
            //遍历所有子节点 
            foreach (XmlNode xn in nodeList)
            {
                //将子节点类型转换为XmlElement类型 
                xe = (XmlElement)xn;
                if (xe.Name == "Author" && xe.InnerText == "amandag")
                {
                    xe.InnerText = "高歌";
                }

                if (xe.GetAttribute("Unit") == "￥")
                {
                    xe.SetAttribute("Unit", "{1}quot;);
                }
            }

            //方法2:
            XmlNode node = xmlDoc.SelectSingleNode("Books//Book[Author=\"moon\"]//Author");
            if(node != null)
            {
                node.InnerText = "宝贝";
            }
    
            xmlDoc.Save("Books.xml");
            MessageBox.Show("数据已更新！");
        }

        private void btnDelete_Click(object sender, EventArgs e)
        {
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load("Books.xml");

            XmlNodeList nodeList = xmlDoc.SelectNodes("Books//Book//Price[@Unit=\"$\"]");

            //遍历所有子节点 
            foreach (XmlNode xn in nodeList)
            {
                XmlElement xe = (XmlElement)xn;
                xe.RemoveAttribute("Unit");
            }
            xmlDoc.Save("Books.xml");
            MessageBox.Show("数据已删除！");
        }

        private XmlElement GetXmlElement(XmlDocument doc, string elementName, string value)
        {
            XmlElement element = doc.CreateElement(elementName);
            element.InnerText = value;
            return element;
        }
    }
}