如何使用LINQ to XML按属性查找XML元素？

using System;
using System.Xml.Linq;

string xml = @"<books>
                  <book id='1'>
                   <title>Book 1</title>
                   <author>Author 1</author>
                  </book>
                  <book id='2'>
                   <title>Book 2</title>
                   <author>Author 2</author>
                  </book>
                </books>";

XElement booksElement = XElement.Parse(xml);

int targetId = 1;
var booksWithTargetId = from book in booksElement.Elements("book")
                        where (int)book.Attribute("id") == targetId
                        select book;

foreach (var book in booksWithTargetId)
{
    Console.WriteLine("Book ID: {0}", book.Attribute("id"));
    Console.WriteLine("Title: {0}", book.Element("title"));
    Console.WriteLine("Author: {0}", book.Element("author"));
}

Book ID: 1
Title: Book 1
Author: Author 1