XML——对XML文档的创建与增删改查

一、创建的第一种方式 

            //1、创建一个XML文档
XmlDocument doc = new XmlDocument();
//2、创建第一行描述信息
XmlDeclaration dec = doc.CreateXmlDeclaration("1.0", "utf-8", null);
//3、将创建的第一行描述信息添加到文档中
doc.AppendChild(dec);
//4、给文档添加根节点
XmlElement Books = doc.CreateElement("Books");
doc.AppendChild(Books);
XmlElement Book = doc.CreateElement("Book");
Books.AppendChild(Book);
XmlElement name = doc.CreateElement("name");
name.InnerText = "水浒传";
Book.AppendChild(name);
XmlElement author = doc.CreateElement("author");
author.InnerText = "匿名";
author.SetAttribute("name", "wjl");
author.SetAttribute("count", "");
Book.AppendChild(author);
doc.Save("Book.xml");
Console.WriteLine("保存成功!");
Console.ReadKey();

创建结果如下:

XML——对XML文档的创建与增删改查

二、创建的第二种方式

   class Program
{
             static void Main(string[] args)
{
                 List<Student> list = new List<Student>();
                 list.Add(new Student(1, "wjl1", 22, "男"));
                 list.Add(new Student(2, "wjl2", 21, "男"));
                 list.Add(new Student(3, "wjl3", 22, "男"));
                 list.Add(new Student(4, "wjl4", 24, "男"));
                 XmlDocument xmldoc = new XmlDocument();
                 XmlDeclaration xmldec = xmldoc.CreateXmlDeclaration("1.0", "utf-8", null);
                xmldoc.AppendChild(xmldec);
                 XmlElement person = xmldoc.CreateElement("Person");
                xmldoc.AppendChild(person);
                 for (int i = 0; i < list.Count; i++)
                {
                     XmlElement stu = xmldoc.CreateElement("student");
                     stu.SetAttribute("ID", list[i].Id.ToString());
                    person.AppendChild(stu);
                     XmlElement name = xmldoc.CreateElement("name");
                     XmlElement age = xmldoc.CreateElement("age");
                     name.InnerText = list[i].Name;
                    age.InnerText = list[i].Age.ToString();
                   stu.AppendChild(name);
                    stu.AppendChild(age);
                }
                 xmldoc.Save("Student.xml");
                Console.WriteLine("Student.xml");
                Console.ReadKey();
            }
        }
         class Student
        {
            int id;
            string name;
            int age;
            string sex;
            public Student(int id, string name, int age, string sex)
            {
                 this.id = id;
                this.name = name;
               this.age = age;
               this.sex = sex;
           }
            public Student()
            {
           }
         }

 创建结果如下:

XML——对XML文档的创建与增删改查

三、对XML文件的添加

            XmlDocument doc = new XmlDocument();
//首先判断文件是否存在,如果存在则追加否则在创建一个
if (File.Exists("Student.xml"))
{
//加载
doc.Load("Student.xml");
//获取根节点,给根节点添加子节点
XmlElement person = doc.DocumentElement;
XmlElement student = doc.CreateElement("student");
student.SetAttribute("ID", "");
person.AppendChild(student);
XmlElement name = doc.CreateElement("name");
XmlElement age = doc.CreateElement("age");
name.InnerText = "zjs";
age.InnerText = "";
student.AppendChild(name);
student.AppendChild(age);
}
else {
}
doc.Save("Student.xml");
Console.WriteLine("Student.xml 保存成功");

四、对XML文档的查询、修改、删除

方法1:

文档结构为:

XML——对XML文档的创建与增删改查

if (File.Exists("order.xml"))
{
doc.Load("order.xml");
// 获取根节点
XmlElement orderElement = doc.DocumentElement;
XmlNodeList orderChildr = orderElement.ChildNodes;
foreach (XmlNode item in orderChildr)
{
Console.WriteLine("节点名称:"+ item.Name + "节点的 InnerText :" + item.InnerText);
}
XmlElement orderitem = orderElement["Items"];
XmlNodeList itemlist = orderitem.ChildNodes;
foreach (XmlNode item in itemlist)
{
Console.WriteLine(item.Attributes["Name"].Value + " " + item.Attributes["Count"].Value);
}
}
else
{
Console.WriteLine("文件不存在!");
}
Console.ReadKey();
// doc.Save("Student.xml");
Console.WriteLine("Student.xml 保存成功");
  

方法2:

            #region 使用XPath的方式来读取XML文件
// 获取文档对象
XmlDocument doc = new XmlDocument();
doc.Load("order.xml");
//获取根节点
XmlElement order = doc.DocumentElement;
// 获取单个节点
//XmlNode xn = order.SelectSingleNode(@"/Order/CustomerName");
XmlNode xn = order.SelectSingleNode(@"/Order/Items/OrderItem[@Name='码表']");
xn.Attributes["Count"].Value = ""; // 修改
doc.Save("Order.xml");
Console.WriteLine(xn.Attributes["Count"].Value);
Console.ReadKey();
#endregion

删除元素指定的特性:

            xn.Attributes.RemoveNamedItem("Count");  //删除元素指定的特性

删除子节点:

            XmlNode xn = order.SelectSingleNode(@"/Order/Items");
XmlNode xnchild = order.SelectSingleNode(@"/Order/Items/OrderItem[@Name = '雨衣']");
xn.RemoveChild(xnchild); //删除指定的子节点

删除当前所有子节点:

            xn.RemoveAll(); //删除当前节点的所有子节点   

删除当前节点的所有特性:

            xnchild.Attributes.RemoveAll(); 
上一篇:程序设计入门——C语言 第3周编程练习 2 数字特征值(5分)


下一篇:记一次MySQL中Waiting for table metadata lock问题的处理