LinqToXML

<Students>
<Student Id ="1">
<Name>张三</Name>
<Address>张三家地址</Address>
</Student>
<Student Id ="2">
<Name>李四</Name>
<Address>李四家地址</Address>
</Student>
</Students>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Xml.Linq;
using StudentManager.Models;

namespace StudentManager
{
public class XmlHelper
{
private XElement Root;

private List<Student> _StuList;
public List<Student> StuList
{
get { return _StuList; }
set { _StuList = value; }
}
string path = HttpRuntime.AppDomainAppPath.ToString() + "App_Data\\Data.xml";

public XmlHelper()
{
Root = Load();
}
public XElement Load()
{
XElement root = XElement.Load(path);
return root;
}
public List<Student> GetAllStudents()
{
List<Student> list = new List<Student>();
var students = Root.Elements("Student");
foreach (var stu in students)
{
Student s = new Student();
s.Id = Convert.ToInt32(stu.Attribute("Id").Value);
s.Name = stu.Element("Name").Value;
s.Address = stu.Element("Address").Value;
list.Add(s);
}
StuList = list;

return list;
}
public Student GetStudentById(int id)
{
Student stu = new Student();

IEnumerable<XAttribute> es = Root.Elements("Student").Attributes("Id");

//XElement el = es.FirstOrDefault(o => o.Value == id.ToString()).Parent;

XElement e = Root.Elements("Student").Single(o =>
{
bool flag = o.Attribute("Id").Value == id.ToString();
if (flag)
{
stu.Id = Convert.ToInt32(o.Attribute("Id").Value);
stu.Name = o.Element("Name").Value;
stu.Address = o.Element("Address").Value;
}
return flag;
});

return stu;
}
public void DeleteStudentById(int id)
{
XElement t = (from stu in Root.Elements("Student")
where stu.Attribute("Id").Value == id.ToString()
select stu).Single() as XElement;
t.Remove();
Root.Save(path);
}
public void UpdateStudent(Student stu)
{
//XElement e = Root.Elements("Student").Single(o => o.Attribute("Id").Value == stu.Id.ToString());
//e.Element("Name").SetValue(stu.Name);
//e.Element("Address").SetValue(stu.Address);
//e.ReplaceWith(new XElement(stu.Name,stu.Address));
Root.Elements("Student").Single(o => o.Attribute("Id").Value == stu.Id.ToString())
.ReplaceWith(new XElement("Student",new XAttribute("Id",stu.Id),
new XElement("Name",stu.Name),
new XElement("Address",stu.Address)));
Root.Save(path);
}
public void CreateStudent(Student stu)
{
int a = GetMaxIndex();
stu.Id = a;

XElement e = Root.Elements("Student").Last();
e.AddAfterSelf(new XElement("Student"
,new XAttribute("Id",stu.Id)
,new XElement("Name",stu.Name)
,new XElement("Address",stu.Address)));
Root.Save(path);
}

private int GetMaxIndex()
{
//int temp = 0;
int maxIndex = Root.Elements("Student").Max(o => Convert.ToInt32(o.Attribute("Id").Value));
//Root.Elements("Student").Max((o) =>
//{
//    temp = (int)o.Attribute("Id");
//    return temp;
//});

return ++maxIndex;
}
}
}