关于LiINQ筛选和排序XML元素的问题-未将对象引用设置到对象的实例。
本帖最后由 JCY1009015337 于 2013-02-18 15:23:48 编辑 代码：
static XElement CreateUserList1()
{
XElement man1 = new XElement("Man",
new XAttribute("ID", "001"),
new XAttribute("Age", "22"),
new XElement("Name", "李四"),
new XElement("XingBie", "男"),
new XElement("Phone", "131123456789"),
new XElement("Emial", "LiSi@126.com"));
XElement man2 = new XElement("Man",
new XAttribute("ID", "002"),
new XAttribute("Age", "23"),
new XElement("Name", "张三"),
new XElement("XingBie", "男"),
new XElement("Phone", "132333456789"),
new XElement("Emial", "Zhangsan@126.com"));
XElement woman1 = new XElement("Woman",
new XAttribute("ID", "003"),
new XAttribute("Age", "19"),
new XElement("Name", "黄花"),
new XElement("XingBie", "女"),
new XElement("Phone", "130003456789"),
new XElement("Emial", "huanghua@126.com"));
XElement userList = new XElement("UserList",new XAttribute("Count","3"),man1,woman1,man2);
return userList;
}
static void QueryComplexElement()//筛选和排序XML元素
{
XElement userList = CreateUserList1();
var oldUsers = from user in userList.Elements() where int.Parse (user.Attribute("Age").Value) > 20 orderby user.Attribute("Age").Value descending select user;

foreach (var item in oldUsers)
Console.WriteLine(item);
var anOldUsers = from user in userList.Elements()
where int.Parse(user.Attribute("Age").Value) > 20
orderby user.Attribute("Age").Value
select new { Name = user.Element("Name").Value,
Age = user.Attribute("Age").Value,
Email = user.Element("Email").Value };
Console.WriteLine();
foreach (var item in anOldUsers)
{
Console.WriteLine(item);
}
}
为什么运行函数QueryComplexElement()后有“未将对象引用设置到对象的实例”的错误？

[解决办法]
new XElement("Emial", "Zhangsan@126.com"));

Email = user.Element("Email").Value
[解决办法]
这代码写的问题多多啊：

void Main()
{
  XElement userList = CreateUserList1();
  
 var anOldUsers = from user in userList.Descendants("Man")
  where user.Attribute("Age") !=null && int.Parse(user.Attribute("Age").Value) > 20
  orderby user.Attribute("Age").Value
  select new { Name = user.Element("Name").Value,
  Age = user.Attribute("Age").Value,
  Email = user.Element("Email").Value };
 
 foreach (var item in anOldUsers)
 {
 Console.WriteLine(item);
 }
}
static XElement CreateUserList1() 
 
 {
 XElement man1 = new XElement("Man",
 new XAttribute("ID", "001"),
 new XAttribute("Age", "22"),
 new XElement("Name", "李四"),
 new XElement("XingBie", "男"), 
 new XElement("Phone", "131123456789"), 
 new XElement("Email", "LiSi@126.com"));
 XElement man2 = new XElement("Man",
new XAttribute("ID", "002"),
new XAttribute("Age", "23"),
new XElement("Name", "张三"),
new XElement("XingBie", "男"),
new XElement("Phone", "132333456789"),
new XElement("Email", "Zhangsan@126.com"));
 XElement woman1 = new XElement("Woman",
new XAttribute("ID", "003"),
new XAttribute("Age", "19"),
new XElement("Name", "黄花"),
new XElement("XingBie", "女"),
new XElement("Phone", "130003456789"),
new XElement("Email", "huanghua@126.com"));
 XElement userList = new XElement("UserList",new XAttribute("Count","3"),man1,woman1,man2);
 return userList;
 }