XmlSerializer xml=new XmlSerializer(typeof(Person))
use(FileStream fs=new FileStream("person.xml",FileMode.Create))
{
    xml.Serialize(fz,p1)
}
Console.WriteLine("ok");
Console.ReadKey();

JavaScrtptSerializer jsSer=new JavaScrtptSerializer();
string msg=jsSer.Serialize(p1);
Console.WriteLine(msg);
Console.ReadKey();

XML的读取
private void button1_Click(object sender, EventArgs e)
    {
        //读取xml
        XDocument document = new XDocument();
        document = XDocument.Load("xdoc.xml");
        XElement rootelement = document.Root;
        TreeNode rootnodes=treeView1.Nodes.Add(rootelement.Name.ToString());
        loadxmltotrees(rootelement,rootnodes.Nodes);
    }
           
    private void loadxmltotrees(XElement rootelement,TreeNodeCollection treenodecollection)
    {
        foreach (XElement item in rootelement.Elements())
        {
            if (item.Elements().Count() == 0)
            {
                treenodecollection.Add(item.Name.ToString()).Nodes.Add(item.Value);
            }
            else
            {
                TreeNode node = treenodecollection.Add(item.Name.ToString());
                loadxmltotrees(item, node.Nodes);
            }                
        }
    }
    
    private void button2_Click(object sender, EventArgs e)
    {
        XmlDocument document1 = new XmlDocument();
        document1.Load("xdoc.xml");
        XmlElement rootelement = document1.DocumentElement;
        TreeNode rootnodes = treeView1.Nodes.Add(rootelement.Name.ToString());
        loadxmldoctotrees(rootelement, rootnodes.Nodes);
    }

    private void loadxmldoctotrees(XmlElement rootelement, TreeNodeCollection treenodecollection)
    {
        foreach (XmlNode item in rootelement.ChildNodes)
        {
            if (item.NodeType == XmlNodeType.Element)
            {
                TreeNode node = treenodecollection.Add(item.Name.ToString());
                loadxmldoctotrees((XmlElement)item, node.Nodes);
            }
            else if (item.NodeType==XmlNodeType.Text|item.NodeType==XmlNodeType.CDATA)
            {
                treenodecollection.Add(item.InnerText);
            }
        }
    }

    private void button3_Click(object sender, EventArgs e)
    {
        XmlDocument document1 = new XmlDocument();
        document1.Load("xdoc.xml");
        //XmlNodeList nodelist = document1.GetElementsByTagName("name");
        //foreach (XmlNode node in nodelist)
        //{
        //    treeView1.Nodes.Add(node.Name.ToString());
        //}
        //===============================
        //XmlElement nodelist = document1.GetElementById("1");
        //treeView1.Nodes.Add(nodelist.Name.ToString());
        //=======================
        XmlNodeList nodelist = document1.SelectNodes("list");//循环搜索
        foreach (XmlNode node in nodelist)
        {
            treeView1.Nodes.Add(node.Name.ToString());
        }
    }

    private void button4_Click(object sender, EventArgs e)
    {
        OpenFileDialog ofd1 = new OpenFileDialog();
        ofd1.Filter = "*.xml|*.XML";
        if(ofd1.ShowDialog()==DialogResult.OK)
        {
            string fullpath = ofd1.FileName;
            XDocument document = XDocument.Load(fullpath);
            XElement root = document.Root;
            IEnumerable<XElement> ie= root.Descendants("person").Where(x=>Convert.ToInt32(x.Attribute("id").Value)>2);
            foreach (var item in ie)
            {
                treeView1.Nodes.Add(item.Name.ToString());
            }
        }
    }
    
xml的写入
private void button1_Click(object sender, EventArgs e)
{
    //
    XmlDocument xmldoc = new XmlDocument();
    //增加文档说明
    XmlDeclaration xmldeclaration = xmldoc.CreateXmlDeclaration("1.0", "utf-8", "yes");
    xmldoc.AppendChild(xmldeclaration);
    //root根
    XmlElement rootelement = xmldoc.CreateElement("school");
    xmldoc.AppendChild(rootelement);
    //class
    XmlElement rootclass = xmldoc.CreateElement("class");
    XmlAttribute attr=xmldoc.CreateAttribute("id");
    attr.Value = "c01";
    rootclass.Attributes.Append(attr);
    rootelement.AppendChild(rootclass);
    //student
    XmlElement rootstudent = xmldoc.CreateElement("student");
    XmlAttribute attrstd = xmldoc.CreateAttribute("sid");
    attrstd.Value = "s011";
    rootstudent.Attributes.Append(attrstd);
    rootclass.AppendChild(rootstudent);
    //
    XmlElement xmlname = xmldoc.CreateElement("name");
    xmlname.InnerText = "玉敏俊";
    rootstudent.AppendChild(xmlname);
    XmlElement xmlname1 = xmldoc.CreateElement("name");
    xmlname1.InnerText = "玉敏俊";
    rootstudent.AppendChild(xmlname1);
    XmlElement xmlage = xmldoc.CreateElement("age");
    xmlage.InnerText = "18";
    rootstudent.AppendChild(xmlage);
    //保存
    xmldoc.Save("school.xml");
    MessageBox.Show("ok");
}

private void button2_Click(object sender, EventArgs e)
{
    List<person> list = new List<person>();
    list.Add(new person() { name = "测试",age=19});
    list.Add(new person() { name = "测试1", age = 20 });
    list.Add(new person() { name = "测试2", age = 21 });
    list.Add(new person() { name = "测试3", age = 22 });
    XmlDocument xml = new XmlDocument();
    XmlDeclaration xmldec = xml.CreateXmlDeclaration("1.0","utf-8","yes");
    xml.AppendChild(xmldec);
    XmlElement xmlroot = xml.CreateElement("list");
    xml.AppendChild(xmlroot);
    for (int i=0;i<list.Count(); i++)
    {
        XmlElement xmlperson = xml.CreateElement("person");
        XmlAttribute xmlattrid = xml.CreateAttribute("id");
        xmlattrid.Value = (i + 1).ToString();
        xmlperson.Attributes.Append(xmlattrid);
        xmlroot.AppendChild(xmlperson);
        XmlElement xmlname = xml.CreateElement("name");
        xmlname.InnerText=list[i].name;
        xmlperson.AppendChild(xmlname);
        XmlElement xmlage = xml.CreateElement("age");
        xmlage.InnerText = list[i].age.ToString();
        xmlperson.AppendChild(xmlage);
    }
    xml.Save("ceshi.xml");
    MessageBox.Show("OK");
}

private void button3_Click(object sender, EventArgs e)
{
    List<person> list = new List<person>();
    list.Add(new person() { name = "测试", age = 19 });
    list.Add(new person() { name = "测试1", age = 20 });
    list.Add(new person() { name = "测试2", age = 21 });
    list.Add(new person() { name = "测试3", age = 22 });
    XDocument xdoc = new XDocument();
    XDeclaration xdes = new XDeclaration("1.0", "utf-8", "yes");
    XElement root = new XElement("list");
    xdoc.Add(root);
    for (int i = 0; i < list.Count; i++)
    {
        XElement xelementperson = new XElement("person");
        xelementperson.SetAttributeValue("id", (i + 1).ToString());
        root.Add(xelementperson);
        xelementperson.SetElementValue("name",list[i].name);
        xelementperson.SetElementValue("age", list[i].age.ToString());
    }
    xdoc.Save("xdoc.xml");
    MessageBox.Show("OK");
    }
}
public class person
{
    public person()
    { }
    public string name { get; set; }
    public int age { get; set; }
}

xml练习
public class person
{
    public person()
    { }
    public person(string id,string name, string age, string Email)
    {
        this.id = id;
        this.name = name;
        this.age = age;
        this.Email = Email;
    }
    public string id { get; set; }
    public string name { get; set; }
    public string age { get; set; }
    public string Email { get; set; }
    public override string ToString()
    {
        return this.name;
    }
}
Dictionary<string, person> dict = new Dictionary<string, person>();
private void button1_Click(object sender, EventArgs e)
{
    person model = new person(textBox1.Text.Trim(), textBox2.Text.Trim(),textBox3.Text.Trim(), textBox4.Text.Trim());
    //
    if (dict.ContainsKey(textBox1.Text.Trim()))
    {
        //已经包含
        dict[model.id] = model;
        person current = listBox1.SelectedItem as person;
        if (current!=null)
        {
            current.id = model.id;
            current.name = model.name;
            current.age = model.age;
            current.Email = model.Email;
        }
        listBox1.Items[listBox1.SelectedIndex] = model; //页面刷新关键的一句
    }
    else
    {
        dict.Add(model.id, model);
        listBox1.Items.Add(model);
    }
    
}
private void cleartextbox()
{
    foreach (Control item in this.Controls)
    {
        if (item is TextBox)
        {
            ((TextBox)item).Text = string.Empty;
        }
    }
}

private void button2_Click(object sender, EventArgs e)
{
    XDocument document = new XDocument();
    XElement root = new XElement("personlist");
    document.Add(root);
    foreach (KeyValuePair<string,person> item in dict)
    {
        XElement personelement = new XElement("person");
        root.Add(personelement);
        personelement.SetElementValue("id",item.Value.id);
        personelement.SetElementValue("name", item.Value.name);
        personelement.SetElementValue("age", item.Value.age);
        personelement.SetElementValue("Email", item.Value.Email);
    }
    document.Save("xml.xml");
    MessageBox.Show("ok");
}

private void Form1_Load(object sender, EventArgs e)
{
    XDocument document = XDocument.Load("xml.xml");
    XElement root = document.Root;
    foreach (XElement item in root.Elements("person"))
    {
        string id = item.Element("id").Value;
        string name = item.Element("name").Value;
        string age = item.Element("age").Value;
        string Email = item.Element("Email").Value;
        person model = new person(id,name,age,Email);
        if (!dict.ContainsKey(model.id))
        {
            dict.Add(model.id,model);
            //
            listBox1.Items.Add(model);
        }
    }
}

private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
    if (listBox1.SelectedItem != null)
    {
        person p = listBox1.SelectedItem as person;
        if (p!=null)
        {
            textBox1.Text = p.id;
            textBox2.Text = p.name;
            textBox3.Text = p.age;
            textBox4.Text = p.Email;
        }
    }
}

/// <summary>
/// 保存
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button1_Click(object sender, EventArgs e)
{
    OpenFileDialog ofd1 = new OpenFileDialog();
    ofd1.Filter = "*jpg|*.JPG|*.GIF|*.GIF|*.BMP|*.BMP";
    if (ofd1.ShowDialog()==DialogResult.OK)
    {
        string fullpath = ofd1.FileName;
        Image im = Image.FromFile(fullpath);
        pictureBox1.Image = im;
    }
    if (pictureBox1.Image!=null)
    {
        MemoryStream ms = new MemoryStream();
        pictureBox1.Image.Save(ms, ImageFormat.Jpeg);
        byte[] imagebtye = ms.GetBuffer();
        //MySqlConnection conn = new MySqlConnection(config.CONNECT_196);
        //conn.Open();
        string str = "insert into ymj.tb_pictrue (pictrue) values(@imageByte)";
        //MySqlCommand comm = new MySqlCommand();
        //comm.Connection = conn;
        //comm.CommandText = str;
        //comm.CommandType = CommandType.Text;
        //comm.Parameters.Add(new MySqlParameter("?imageByte", MySqlDbType.MediumBlob)).Value = imagebtye;
        //comm.ExecuteNonQuery();
        MySqlParameter sp = new MySqlParameter("@imageByte",imagebtye);
        MySqlHelper.ExecuteDataset(config.CONNECT_196,str,sp);               
        MessageBox.Show("成功");
    }
    //OpenFileDialog1.Filter = "*jpg|*.JPG|*.GIF|*.GIF|*.BMP|*.BMP";
    //if (OpenFileDialog1.ShowDialog()==DialogResult.OK)
    //{
    //    fullpath = OpenFileDialog1.FileName;
    //    Bitmap bmp = new Bitmap(fullpath);
    //    MemoryStream ms = new MemoryStream();
    //    bmp.Save(ms,ImageFormat.Gif);
    //    byte[] arr = new byte[ms.Length];
    //    string pic = Convert.ToBase64String(arr);
    //    MySqlHelper.ExecuteNonQuery(config.CONNECT_196,sql);
    //}
}
/// <summary>
/// 读取
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button2_Click(object sender, EventArgs e)
{
    string str = "select pictrue from ymj.tb_pictrue order by id desc";
    MySqlDataReader dr=MySqlHelper.ExecuteReader(config.CONNECT_196,str);
    if (dr.Read())
    {
        byte[] imagebyte = new byte[dr.GetBytes(0, 0, null, 0, int.MaxValue)];
        dr.GetBytes(0, 0, imagebyte, 0, imagebyte.Length);
        MemoryStream imagems = new MemoryStream(imagebyte);
        Image image = Image.FromStream(imagems,true);
        pictureBox1.Image = image;
    }
}