使用LINQ-to-XML选择元素

Question

我有这个XML文件：

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<games>
  <game id="123456" name="501">
    <player id="1">
      <name>john</name>
      <score>495</score>
      <movesLeft>15</movesLeft>
      <won>No</won>
      <completed>uncompleted</completed>
    </player>
    <player id="2">
      <name>
         konj
      </name>
      <score>501</score>
      <movesLeft>15</movesLeft>
      <won>No</won>
      <completed>uncompleted</completed>
    </player>
  </game>
</games>

并且我创建了此查询，但无法编译：

string path = @"D:\xml\dartDatabase.xml";
XElement file = XElement.Load(path);

var query = from f in file.Element("games").Elements("game")
            where (string)f.Attribute("id") == "123"
            select (string)f.Element("name");

它强调第一行（ from节开始），并指出错误是：

“哪里”找不到，是您缺少对System.Core.dll的引用还是对System.Linq使用指令

怎么了？

Answer 1

using System.Linq;添加using System.Linq;