创建xml文件，并保存文件->xml

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

namespace CreateXml
{
    class Program
    {
        static void Main(string[] args)
        {
            Program app = new Program();
            app.CreateXmlFile();
        }
        public void CreateXmlFile()
        {
            XmlDocument xmlDoc = new XmlDocument();
            //创建类型声明节点
            //XmlNode node=xmlDoc.CreateXmlDeclaration("1.0","utf-8","");
            //xmlDoc.AppendChild(node);
            //创建根节点

            XmlNode root = xmlDoc.CreateElement("annotation");
            xmlDoc.AppendChild(root);

            CreateNode(xmlDoc,root, "folder", "VOC2007");

            CreateNode(xmlDoc, root, "filename", "000001.jpg");

            XmlNode node3 = xmlDoc.CreateNode(XmlNodeType.Element, "source", null);
            CreateNode(xmlDoc, node3, "database", "The VOC2007 Database");
            CreateNode(xmlDoc, node3, "annotation", "PACAL VOC2007");
            CreateNode(xmlDoc, node3, "image", "flickr");
            CreateNode(xmlDoc, node3, "flickrid", "341012865");
            root.AppendChild(node3);

            XmlNode node4 = xmlDoc.CreateNode(XmlNodeType.Element, "owner", null);
            CreateNode(xmlDoc, node4, "flickrid", "Fried Camels");
            CreateNode(xmlDoc, node4, "name", "Jinky the Fruit Bat");
            root.AppendChild(node4);

            XmlNode node5 = xmlDoc.CreateNode(XmlNodeType.Element, "size", null);
            CreateNode(xmlDoc, node5, "width", "353");
            CreateNode(xmlDoc, node5, "heigh"," 500");
            CreateNode(xmlDoc, node5, "depth", "3");
            root.AppendChild(node5);

            CreateNode(xmlDoc, root, "segmented", "0");

            //多一层节点
            XmlNode node7 = xmlDoc.CreateNode(XmlNodeType.Element, "object", null);
            CreateNode(xmlDoc, node7, "name", "dog");
            CreateNode(xmlDoc, node7, "pose", "Left");
            CreateNode(xmlDoc, node7, "truncated", " 1");
            CreateNode(xmlDoc, node7, "difficult", " 0");
            XmlNode node70 = xmlDoc.CreateNode(XmlNodeType.Element, "obndbox", null);
            CreateNode(xmlDoc, node70, "xmin"," 48");
            CreateNode(xmlDoc, node70, "ymin", "240");
            CreateNode(xmlDoc,node70,"xmax","195");
            CreateNode(xmlDoc, node70, "ymax", "371");
            node7.AppendChild(node70);
            root.AppendChild(node7);

            XmlNode node8 = xmlDoc.CreateNode(XmlNodeType.Element, "object", null);
            CreateNode(xmlDoc, node8, "name", "person");
            CreateNode(xmlDoc, node8, "pose", "Left");
            CreateNode(xmlDoc, node8, "truncated", "1");
            CreateNode(xmlDoc, node8, "difficult", "0");

            XmlNode node80 = xmlDoc.CreateNode(XmlNodeType.Element, "object", null);
            CreateNode(xmlDoc, node80, "xmin", " 8");
            CreateNode(xmlDoc, node80, "ymin", "12");
            CreateNode(xmlDoc, node80, "xmax", "352");
            CreateNode(xmlDoc, node80, "ymax", "498");
            node8.AppendChild(node80);
            root.AppendChild(node8);
            try
            {
                xmlDoc.Save("C:/Users/`/Desktop/my.xml");//保存路径
            }
            catch (Exception e)
            {
                //显示错误信息
                Console.WriteLine(e.Message);
            }
            //Console.ReadLine();
        }

        /// <summary>
        /// 创建节点
        /// </summary>
        /// <param name="xmldoc"></param>  xml文档
        /// <param name="parentnode"></param>父节点
        /// <param name="name"></param>  节点名
        /// <param name="value"></param>  节点值
        ///
        public void CreateNode(XmlDocument xmlDoc, XmlNode parentNode, string name, string value)
        {
            XmlNode node = xmlDoc.CreateNode(XmlNodeType.Element, name, null);
            node.InnerText = value;
            parentNode.AppendChild(node);
        }
    }
}

<annotation>
  <folder>VOC2007</folder>
  <filename>000001.jpg</filename>
  <source>
    <database>The VOC2007 Database</database>
    <annotation>PACAL VOC2007</annotation>
    <image>flickr</image>
    <flickrid>341012865</flickrid>
  </source>
  <owner>
    <flickrid>Fried Camels</flickrid>
    <name>Jinky the Fruit Bat</name>
  </owner>
  <size>
    <width>353</width>
    <heigh>500</heigh>
    <depth>3</depth>
  </size>
  <segmented>0</segmented>
  <object>
    <name>dog</name>
    <pose>Left</pose>
    <truncated>1</truncated>
    <difficult>0</difficult>
    <obndbox>
      <xmin>48</xmin>
      <ymin>240</ymin>
      <xmax>195</xmax>
      <ymax>371</ymax>
    </obndbox>
  </object>
  <object>
    <name>person</name>
    <pose>Left</pose>
    <truncated>1</truncated>
    <difficult>0</difficult>
    <object>
      <xmin>8</xmin>
      <ymin>12</ymin>
      <xmax>352</xmax>
      <ymax>498</ymax>
    </object>
  </object>
</annotation>