C # XML is used to store data

Create an XML document

First reference System.Xmlnamespace

One example 1. Initialization

XmlDocument xd = new XmlDocument();

2. Create XML declaration header file

XmlDeclaration xdt = xd.CreateXmlDeclaration("1.0", "utf-8", null);
xd.AppendChild(xdt);

3. Create a unique root

XmlElement Students = xd.CreateElement("Students");

4. add attributes to the root node (may not be added)

Students.SetAttribute("name", "学生信息");

5. The root node is added to the XML file

xd.AppendChild(Students);

6. Create two nodes

XmlElement student = xd.CreateElement("student");
student.SetAttribute("stuNum", "100100100");
Students.AppendChild(student);

7. padding value to the secondary node

XmlElement name = xd.CreateElement("name");
name.InnerText = "小明";
XmlElement sex = xd.CreateElement("sex");
sex.InnerText = "男";
student.AppendChild(name);
student.AppendChild(sex);

8. Save

xd.Save("StuMS.xml");

9. results

<?xml version="1.0" encoding="utf-8"?>
<Students name="学生信息">
  <student stuNum="100100100">
    <name>小明</name>
    <sex>男</sex>
  </student>
</Students>

Read the information in an XML document

First you have to load an XML document

XmlDocument xd = new XmlDocument();
xd.Load("StuMS.xml");

1. read using the index

//查找标签值
string Name = stuNode.ChildNodes[0].InnerText;
//查找标签属性
string StuNum = stuNode.Attributes[0].Value;

2. Using Xpath query

// 常用查询方式
//1. "根节点/父节点/子节点"
//2. "//节点"
//3. "根节点/父节点[@父节点属性 = 'value' ]"
//4. "根节点/父节点[子节点 = 'value' ]"

XmlNode stuNode = xd.SelectSingleNode("Students/student[@stuNum =" + stuNum + "]");//可以获得指定stuNum的一个节点
XmlNodeList stuNodeList = xd.SelectNodes("Students/student[sex = '男' ]");//可以获得指定性别的集合

Modify the information in an XML document

Found -> Edit -> Save

//节点信息修改
stuNode.SelectSingleNode("name").InnerText = value;
stuNode.SelectSingleNode("name").InnerXml = value;
//属性信息修改
student.Attributes["stuNum"].Value = value;

InnerText displays only content 小明男InnerXml will be displayed along with the label<name>小明</name><sex>男</sex>

Delete XML document information

//从当前节点获取父节点，从父节点删除当前节点
stuNode.ParentNode.RemoveChild(studentNode);
//从父节点直接删除子节点
stuNode.RemoveChild(studentNode)