把list集合的内容写入到Xml中，通过XmlDocument方式写入Xml文件中

 List<Person> list = new List<Person>

{
new Person{Name="张三",Age=20,Email="zs@zhansan.com"},
new Person{Name="李四",Age=30,Email="ls@lisi.com"},
new Person{Name="王五",Age=22,Email="ww@wangwu.com"},
new Person{Name="赵柳",Age=20,Email="xl@zhaoliou.com"},
new Person{Name="玄武",Age=20,Email="xw@xuanwu.com"},
new Person{Name="白虎",Age=20,Email="bh@baihu.com"},
};

//实例化XMLDocument对象
XmlDocument xmldoc = new XmlDocument();

//增加一个Xml文档声明

XmlDeclaration xmldeclaration = xmldoc.CreateXmlDeclaration("1.0", "utf-8", null);

//创建Xml文档根节点

XmlElement xmlelement = xmldoc.CreateElement("List");

//添加到Xml文档中
xmldoc.AppendChild(xmlelement);

//循环添加

for (int i = 0; i < list.Count; i++)
{

//创建根节点下的子节点
XmlElement xmlperson = xmldoc.CreateElement("Person");

//创建子节点的属性ID
XmlAttribute xmlattribute = xmldoc.CreateAttribute("id");

//给属性值赋值
xmlattribute.Value = (i + 1).ToString();

//添加到子节点中
xmlperson.Attributes.Append(xmlattribute);

//添加Name节点

XmlElement xmlName = xmldoc.CreateElement("Name");

//给Name文本赋值
xmlName.InnerText = list[i].Name;

//添加到Person节点下
xmlperson.AppendChild(xmlName);

//以下节点类似

XmlElement xmlAge = xmldoc.CreateElement("Age");
xmlAge.InnerText = list[i].Age.ToString();
xmlperson.AppendChild(xmlAge);

XmlElement xmlEmail = xmldoc.CreateElement("Email");
xmlEmail.InnerText = list[i].Email;
xmlperson.AppendChild(xmlEmail);

xmlelement.AppendChild(xmlperson);

}

//创建文件保存在Xml文件夹中

string fileName = Server.MapPath("/Xml/List.xml");

xmldoc.Save(fileName);