c# XML增删改查

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Xml;
namespace _04对XML实现增删改查
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        List<User> listUsers = new List<User>();
        private void Form1_Load(object sender, EventArgs e)
        {
            LoadData();

        }

        //加载数据
        private void LoadData()
        {
            // listUsers = new List<User>();
            //设置DataGridView的样式
            //取消显示第一列
            dataGridView1.RowHeadersVisible = false;
            //将单元格选中变成整行选中
            dataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
            XmlDocument doc = new XmlDocument();
            doc.Load("haodongxi.xml");
            //获得根节点
            XmlElement users = doc.DocumentElement;
            //获得根节点下面所有的子节点
            XmlNodeList xnl = users.ChildNodes;
            listUsers.Clear();
            foreach (XmlNode item in xnl)
            {
                User user = new User();
                user.ID = int.Parse(item.Attributes["id"].Value);
                user.Name = item["name"].InnerText;
                user.Age = int.Parse(item["age"].InnerText);
                user.Gender = char.Parse(item["gender"].InnerText);
                user.Password = item["password"].InnerText;
                listUsers.Add(user);
            }
            //把集合作为数据源赋值给DatagridView
            dataGridView1.DataSource = null;
            //如果要dgv数据放生改变，则必须要给它的DataSource重新复制
            dataGridView1.DataSource = listUsers;
        }

        private void btnZhuCe_Click(object sender, EventArgs e)
        {
            XmlDocument doc = new XmlDocument();
            doc.Load("haodongxi.xml");

            XmlElement users = doc.DocumentElement;

            XmlElement user = doc.CreateElement("user");
            user.SetAttribute("id", txtID.Text.Trim());
            users.AppendChild(user);

            XmlElement name = doc.CreateElement("name");
            name.InnerText = txtName.Text;
            user.AppendChild(name);

            XmlElement age = doc.CreateElement("age");
            age.InnerText = txtAge.Text;
            user.AppendChild(age);

            XmlElement gender = doc.CreateElement("gender");
            gender.InnerText = rdoMan.Checked ? "男" : "女";
            user.AppendChild(gender);

            XmlElement password = doc.CreateElement("password");
            password.InnerText = txtPwd.Text;
            user.AppendChild(password);

            //切记 保存
            doc.Save("haodongxi.xml");
            //重新加载数据
            LoadData();
            MessageBox.Show("注册成功");
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string id = txtUpdateID.Text;

            XmlDocument doc = new XmlDocument();
            doc.Load("haodongxi.xml");
            XmlElement users = doc.DocumentElement;

            //xPath  Path  XMLPath

            XmlNode xn = users.SelectSingleNode("/Users/user[@id='" + id + "']");
            // /"Users/user[@id='" +  "']"
            //"/Users/user[@id='']"

            xn["name"].InnerText = txtUpdateName.Text.Trim();
            xn["age"].InnerText = txtUpdateAge.Text.Trim();
            xn["gender"].InnerText = rdoUpdateMan.Checked ? "男" : "女";
            xn["password"].InnerText = txtUpdatePwd.Text;

            doc.Save("haodongxi.xml");
            LoadData();
            MessageBox.Show("修改成功");

        }

        private void 删除ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            //删除指定数据
            //获得选中行的ID
            string id = dataGridView1.SelectedRows[].Cells[].Value.ToString();

            XmlDocument doc = new XmlDocument();
            doc.Load("haodongxi.xml");

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

            //通过根节点 使用XPath路径找到id=...的节点;
            XmlNode xn = users.SelectSingleNode("/Users/user[@id='" + id + "']");

            //开始删除

            users.RemoveChild(xn);

            doc.Save("haodongxi.xml");
            MessageBox.Show("删除成功");

            LoadData();

        }

        private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            txtUpdateID.Text = dataGridView1.SelectedRows[].Cells[].Value.ToString();

            txtUpdateName.Text = dataGridView1.SelectedRows[].Cells[].Value.ToString();

            txtUpdateAge.Text = dataGridView1.SelectedRows[].Cells[].Value.ToString();

            string gender = dataGridView1.SelectedRows[].Cells[].Value.ToString();
            if (gender == "男")
            {
                rdoUpdateMan.Checked = true;
            }
            else
            {
                rdoUpdateWoman.Checked = true;
            }

            txtUpdatePwd.Text = dataGridView1.SelectedRows[].Cells[].Value.ToString();

        }
    }
}