static void Main(string[] args)
 {
  //通过代码来创建XML文档
  //1、引用命名空间
  //2、创建XML文档对象
  XmlDocument doc = new XmlDocument();
  //3、创建第一个行描述信息，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");
  //将book添加到根节点
  books.AppendChild(book1);
  //6、给Book1添加子节点
  XmlElement name1 = doc.CreateElement("Name");
  name1.InnerText = "三国演义";
  book1.AppendChild(name1);

  XmlElement price1 = doc.CreateElement("Price");
  price1.InnerText = "70";
  book1.AppendChild(price1);

  XmlElement des1 = doc.CreateElement("Des");
  des1.InnerText = "好看";
  book1.AppendChild(des1);

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


  XmlElement name2 = doc.CreateElement("Name");
  name2.InnerText = "西游记";
  book2.AppendChild(name2);

  XmlElement price2= doc.CreateElement("Price");
  price2.InnerText = "80";
  book2.AppendChild(price2);

  XmlElement des2 = doc.CreateElement("Des");
  des2.InnerText = "还不错";
  book2.AppendChild(des2);

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

static void Main(string[] args)
 {
  XmlDocument doc = new XmlDocument();
  XmlDeclaration dec = doc.CreateXmlDeclaration("1.0", "utf-8","yes");
  doc.AppendChild(dec);

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

  XmlElement customerName = doc.CreateElement("CustomerName");
  customerName.InnerText = "张三";
  order.AppendChild(customerName);

  XmlElement customerNumber = doc.CreateElement("CustomerNumber");
  customerNumber.InnerText = "1010101";
  order.AppendChild(customerNumber);


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

  XmlElement orderItem1 = doc.CreateElement("OrderItem");
  //给节点添加属性
  orderItem1.SetAttribute("Name", "单反");
  orderItem1.SetAttribute("Count", "1120");
  items.AppendChild(orderItem1);

  XmlElement orderItem2 = doc.CreateElement("OrderItem");
  //给节点添加属性
  orderItem2.SetAttribute("Name", "书");
  orderItem2.SetAttribute("Count", "30");
  items.AppendChild(orderItem2);

  XmlElement orderItem3 = doc.CreateElement("OrderItem");
  //给节点添加属性
  orderItem3.SetAttribute("Name", "手机");
  orderItem3.SetAttribute("Count", "2000");
  items.AppendChild(orderItem3);

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

  
 }

 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);
  //创建跟节点
  books = doc.CreateElement("Books");
  doc.AppendChild(books);
  }
  //5、给根节点Books创建子节点
  XmlElement book1 = doc.CreateElement("Book");
  //将book添加到根节点
  books.AppendChild(book1);


  //6、给Book1添加子节点
  XmlElement name1 = doc.CreateElement("Name");
  name1.InnerText = "c#开发大全";
  book1.AppendChild(name1);

  XmlElement price1 = doc.CreateElement("Price");
  price1.InnerText = "110";
  book1.AppendChild(price1);

  XmlElement des1 = doc.CreateElement("Des");
  des1.InnerText = "看不懂";
  book1.AppendChild(des1);


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

 }

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

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

  //获得子节点 返回节点的集合
  XmlNodeList xnl = books.ChildNodes;

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

 static void Main(string[] args)
 {
  //读取带属性的XML文档

  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();
}

static void Main(string[] args)
 {
  //改变属性的值
  XmlDocument doc = new XmlDocument();
  doc.Load("Order.xml");
  XmlNode xn = doc.SelectSingleNode("/Order/Items/OrderItem[@Name='单反']");
  xn.Attributes["Count"].Value = "2000";
  xn.Attributes["Name"].Value = "电脑";
  doc.Save("Order.xml");
  Console.WriteLine("保存成功");

  Console.ReadKey();
 }

 static void Main(string[] args)
 {
  XmlDocument doc = new XmlDocument();
  doc.Load("Order.xml");
  XmlNode xn = doc.SelectSingleNode("/Order/Items");
  xn.RemoveAll();
  doc.Save("Order.xml");
  Console.WriteLine("删除成功");
  Console.ReadKey();
 }