XML是yange区分大小写的。
XML标签也是成对出现的。

创建XML文档

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;

namespace _01创建XML
{
    class Program
    {
        static void Main(string[] args)
        {
            //通过代码来创建XML文档
            //1、引入命名空间

            //2、创建XML文档对象
            XmlDocument doc = new XmlDocument();
            
            //3、创建第一行描述信息，并且添加到doc文档中
            XmlDeclaration dec = doc.CreateXmlDeclaration("1.0", "utf-8", null);
            doc.AppendChild(dec);
            
            //4、创建根节点
            XmlElement books = doc.CreateElement("Books");
            //将根节点添加到文档中
            doc.AppendChild(books);

            //5、给根节点Books创建子节点
            XmlElement book1 = doc.CreateElement("Book");
            books.AppendChild(book1);

            XmlElement book1Name = doc.CreateElement("Name");
            book1Name.InnerText = "红楼";
            book1.AppendChild(book1Name);

            XmlElement book1Price = doc.CreateElement("Price");
            book1Price.InnerText = "100";
            book1.AppendChild(book1Price);

            XmlElement book1Des = doc.CreateElement("Des");
            book1Des.InnerText = "石头记";
            book1.AppendChild(book1Des);


            XmlElement book2 = doc.CreateElement("Book");
            books.AppendChild(book2);

            XmlElement book2Name = doc.CreateElement("Name");
            book2Name.InnerText = "三国";
            book2.AppendChild(book2Name);

            XmlElement book2Price = doc.CreateElement("Price");
            book2Price.InnerText = "190";
            book2.AppendChild(book2Price);

            XmlElement book2Des = doc.CreateElement("Des");
            book2Des.InnerText = "合久必分";
            book2.AppendChild(book2Des);

            doc.Save("Books.xml");
            Console.WriteLine("保存成功");
            Console.ReadKey();
        }
    }
}

查看创建的XML

结果

创建带属性的XML文档

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;

namespace _02创建带属性的XML文档
{
    class Program
    {
        static void Main(string[] args)
        {
            XmlDocument doc = new XmlDocument();
            XmlDeclaration dec = doc.CreateXmlDeclaration("1.0", "utf-8", null);
            doc.AppendChild(dec);

            XmlElement order = doc.CreateElement("Order");
            doc.AppendChild(order);

            XmlElement customerName = doc.CreateElement("CustomerName");
            customerName.InnerXml = "小明";
            order.AppendChild(customerName);

            XmlElement customerName2 = doc.CreateElement("CustomerName");
            customerName2.InnerText = "大白";
            order.AppendChild(customerName2);

            XmlElement items = doc.CreateElement("Items");
            order.AppendChild(items);

            XmlElement orderItem1 = doc.CreateElement("OrderItem");
            //给节点添加属性
            orderItem1.SetAttribute("Name", "码表");
            orderItem1.SetAttribute("Count", "10");
            items.AppendChild(orderItem1);

            XmlElement orderItem2 = doc.CreateElement("OrderItem");
            //给节点添加属性
            orderItem2.SetAttribute("Name", "iphone8");
            orderItem2.SetAttribute("Count", "100");
            items.AppendChild(orderItem2);

            doc.Save("Order.xml");
            Console.ReadKey();
        }
    }
}

结果

追加XML

原有的XML

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.IO;

namespace _03追加XML
{
    class Program
    {
        static void Main(string[] args)
        {
            //追加XML文档
            XmlDocument doc = new XmlDocument();
            XmlElement books;
            if (File.Exists("Books.xml"))
            {
                //如果文件存在，加载XML
                doc.Load("Books.xml");
                //获得文件的根节点
                books = doc.DocumentElement;
            }
            else {

                //如果文件不存在
                //创建第一行
                XmlDeclaration dec = doc.CreateXmlDeclaration("1.0", "utf-8", null);
                doc.AppendChild(dec);
                //创建根节点
                books = doc.CreateElement("Books");
                doc.AppendChild(books);
            }


            //5、给根节点Books创建子节点
            XmlElement book1 = doc.CreateElement("Book");
            books.AppendChild(book1);

            XmlElement book1Name = doc.CreateElement("Name");
            book1Name.InnerText = "西游记";
            book1.AppendChild(book1Name);

            XmlElement book1Price = doc.CreateElement("Price");
            book1Price.InnerText = "100";
            book1.AppendChild(book1Price);

            XmlElement book1Des = doc.CreateElement("Des");
            book1Des.InnerText = "孙猴子";
            book1.AppendChild(book1Des);
            
          doc.Save("Books.xml");
        }
    }
}

追加后的结果

读取XML

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;

namespace _04读取XML
{
    class Program
    {
        static void Main(string[] args)
        {
            //加载要读取的XML
            XmlDocument doc = new XmlDocument();
            doc.Load("BookS.xml");

            //获得根节点
            XmlElement books = doc.DocumentElement;

            //获得子节点
            XmlNodeList xnl = books.ChildNodes;

            foreach (XmlNode item in xnl)
            {
                Console.WriteLine(item.InnerText);
            }

            Console.ReadKey();
        }
    }
}

读取结果

读取带属性的XML

XmlDocument doc = new XmlDocument();
doc.Load("Order.xml");
XmlNodeList xnl = doc.SelectNodes("/Order/Items/OrderItem");

foreach (XmlNode node in xnl)
{
    Console.WriteLine(node.Attributes["Name"].Value);
    Console.WriteLine(node.Attributes["Count"].Value);
 }

Console.ReadKey();

读取结果

删除节点

//删除节点
XmlDocument doc = new XmlDocument();
doc.Load("Order.xml");
XmlNode xn = doc.SelectSingleNode("/Order/Items");
xn.RemoveAll();
doc.Save("Order.xml");

原有XML文档

运行结果