using System;
using System.Xml.Linq;

class Program
{
    static void Main()
    {
        try
        {
            // 從文件加載XML
            XDocument doc = XDocument.Load("books.xml");
            
            // 處理XML...
        }
        catch (Exception ex)
        {
            Console.WriteLine($"加載XML時(shí)出錯(cuò): {ex.Message}");
        }
    }
}

string xmlString = @"
<root>
    <element attribute='value'>文本內(nèi)容</element>
</root>";

XDocument doc = XDocument.Parse(xmlString);

// 創(chuàng)建一個(gè)簡(jiǎn)單的XML文檔
XDocument doc = new XDocument(
    new XDeclaration("1.0", "utf-8", "yes"),
    new XComment("這是一個(gè)示例XML文檔"),
    new XElement("catalog",
        new XElement("book",
            new XAttribute("id", "bk101"),
            new XElement("title", "XML編程指南"),
            new XElement("author", "張三"),
            new XElement("price", 49.99)
        ),
        new XElement("book",
            new XAttribute("id", "bk102"),
            new XElement("title", "C#高級(jí)編程"),
            new XElement("author", "李四"),
            new XElement("price", 69.99)
        )
    )
);

// 保存到文件
doc.Save("books.xml");

// 假設(shè)我們已經(jīng)加載了包含書籍信息的XML文檔
XDocument doc = XDocument.Load("books.xml");

// 查詢所有書籍
var books = from book in doc.Descendants("book")
            select book;

// 查詢價(jià)格大于50的書籍
var expensiveBooks = from book in doc.Descendants("book")
                     where (decimal)book.Element("price") > 50
                     select new
                     {
                         Title = (string)book.Element("title"),
                         Price = (decimal)book.Element("price")
                     };

// 查詢作者為"張三"的書籍
var zhangsanBooks = doc.Descendants("book")
                       .Where(b => (string)b.Element("author") == "張三")
                       .Select(b => new
                       {
                           Title = (string)b.Element("title"),
                           Price = (decimal)b.Element("price")
                       });

// 按作者分組統(tǒng)計(jì)書籍?dāng)?shù)量
var booksByAuthor = doc.Descendants("book")
                       .GroupBy(b => (string)b.Element("author"))
                       .Select(g => new
                       {
                           Author = g.Key,
                           BookCount = g.Count(),
                           AveragePrice = g.Average(b => (decimal)b.Element("price"))
                       });

// 找出每個(gè)作者最貴的書
var mostExpensiveBooks = doc.Descendants("book")
                           .GroupBy(b => (string)b.Element("author"))
                           .Select(g => g.OrderByDescending(b => (decimal)b.Element("price")).First());

// 添加新元素
doc.Root.Add(
    new XElement("book",
        new XAttribute("id", "bk103"),
        new XElement("title", "ASP.NET MVC實(shí)戰(zhàn)"),
        new XElement("author", "王五"),
        new XElement("price", 79.99)
    )
);

// 在特定元素后添加新元素
XElement firstBook = doc.Descendants("book").First();
firstBook.AddAfterSelf(
    new XElement("book",
        new XAttribute("id", "bk104"),
        new XElement("title", "LINQ編程指南"),
        new XElement("author", "趙六"),
        new XElement("price", 59.99)
    )
);

// 添加新屬性
foreach (var book in doc.Descendants("book"))
{
    book.Add(new XAttribute("category", "Programming"));
}

// 更新元素內(nèi)容
foreach (var book in doc.Descendants("book"))
{
    decimal price = (decimal)book.Element("price");
    book.Element("price").Value = (price * 1.1m).ToString("F2"); // 價(jià)格上調(diào)10%
}

// 更新特定元素
XElement bookToUpdate = doc.Descendants("book")
                          .FirstOrDefault(b => (string)b.Attribute("id") == "bk101");
if (bookToUpdate != null)
{
    bookToUpdate.Element("title").Value = "XML編程指南（第2版）";
}

// 更新屬性值
foreach (var book in doc.Descendants("book"))
{
    XAttribute categoryAttr = book.Attribute("category");
    if (categoryAttr != null)
    {
        categoryAttr.Value = "Computer Science";
    }
}

// 刪除特定元素
XElement bookToRemove = doc.Descendants("book")
                          .FirstOrDefault(b => (string)b.Attribute("id") == "bk102");
if (bookToRemove != null)
{
    bookToRemove.Remove();
}

// 刪除所有價(jià)格低于60的書籍
doc.Descendants("book")
   .Where(b => (decimal)b.Element("price") < 60)
   .Remove();

// 刪除特定屬性
foreach (var book in doc.Descendants("book"))
{
    XAttribute categoryAttr = book.Attribute("category");
    if (categoryAttr != null)
    {
        categoryAttr.Remove();
    }
}

// 定義一個(gè)簡(jiǎn)單的書籍類
public class Book
{
    public string Id { get; set; }
    public string Title { get; set; }
    public string Author { get; set; }
    public decimal Price { get; set; }
}

// 從XML轉(zhuǎn)換為對(duì)象列表
List<Book> books = doc.Descendants("book")
                     .Select(b => new Book
                     {
                         Id = (string)b.Attribute("id"),
                         Title = (string)b.Element("title"),
                         Author = (string)b.Element("author"),
                         Price = (decimal)b.Element("price")
                     })
                     .ToList();

// 從對(duì)象列表轉(zhuǎn)換為XML
XElement newCatalog = new XElement("catalog",
    books.Select(b => new XElement("book",
        new XAttribute("id", b.Id),
        new XElement("title", b.Title),
        new XElement("author", b.Author),
        new XElement("price", b.Price)
    ))
);

// 需要引入Newtonsoft.Json包
using Newtonsoft.Json;

// XML轉(zhuǎn)JSON
string json = JsonConvert.SerializeXNode(doc);

// JSON轉(zhuǎn)XML
XDocument docFromJson = JsonConvert.DeserializeXNode(json);