<?xml version="1.0" encoding="utf-8" ?>
<SystemInfo>
  <Class name="News" desc="文章栏目">
    <Item name="NewsInfo" desc="新闻资讯">1</Item>
    <Item name="MediaCoverage" desc="媒体报道">2</Item>
    <Item name="Story" desc="爱心故事">3</Item>
  </Class>
</SystemInfo>

public class SystemInfo
{
    public string Id { get; set; }
    public string Name { get; set; }
    public string Desc { get; set; }
}

SystemInfo systemInfo = new SystemInfo();
List<SystemInfo> systemInfoList = new List<SystemInfo>();
XDocument doc = new XDocument();
doc = XDocument.Load("SystemInfo.xml");
var classData = http://www.mamicode.com/(from n in doc.Root.Elements("Class")
                where n.Attribute("name").Value =http://www.mamicode.com/= "News"
                select n).ToList();
foreach (var item in classData.Elements("Item"))
{
    systemInfo.Id = item.Value;
    systemInfo.Name = item.Attribute("name").Value;
    systemInfo.Desc = item.Attribute("desc").Value;
    systemInfoList.Add(systemInfo);
}