<?xml version="1.0" encoding="iso-8859-1"?>
<bookstore>
 <book id="1" category="COOKING">
  <title lang="en">Everyday Italian</title>
  <author>Giada De Laurentiis</author>
  <year>2005</year>
  <price>30.00</price>
 </book>
 <book id="2" category="CHILDREN">
  <title lang="en">Harry Potter</title>
  <author>J K. Rowling</author>
  <year>2005</year>
  <price>29.99</price>
 </book>
 <book id="3" category="WEB">
  <title lang="en">XQuery Kick Start</title>
  <author>James McGovern</author>
  <author>Per Bothner</author>
  <author>Kurt Cagle</author>
  <author>James Linn</author>
  <author>Vaidyanathan Nagarajan</author>
  <year>2003</year>
  <price>49.99</price>
 </book>
 <book id="4" category="WEB">
  <title lang="en">Learning XML</title>
  <author>Erik T. Ray</author>
  <year>2003</year>
  <price>39.95</price>
 </book>
</bookstore>

public class BookInfo
{
  /// <summary>
  /// 圖書ID
  /// </summary>
  public int BookId { set; get; }
  /// <summary>
  /// 圖書名稱
  /// </summary>
  public string Title { set; get; }
  /// <summary>
  /// 圖書分類
  /// </summary>
  public string Category { set; get; }
  /// <summary>
  /// 圖書語言
  /// </summary>
  public string Language { set; get; }
  /// <summary>
  /// 圖書作者
  /// </summary>
  public string Author { set; get; }
  /// <summary>
  /// 出版時間
  /// </summary>
  public string Year { set; get; }
  /// <summary>
  /// 銷售價格
  /// </summary>
  public decimal Price { set; get; }
}

using System.Xml;  //引用相關文件
public class BookInfoBLL
{
  private string _basePath = AppDomain.CurrentDomain.SetupInformation.ApplicationBase + @"/xml/Books.xml"; //XML文件路徑
  private XmlDocument _booksXmlDoc = null;  //創(chuàng)建XML文檔對象
  public BookInfoBLL()
  {
    try
    {
      _booksXmlDoc = new XmlDocument(); //初始化XML文檔對象
      _booksXmlDoc.Load(_basePath);   //加載指定的XML文檔
    }
    catch (Exception ex)
    {
      throw new Exception("加載XML文檔出錯：" + ex.Message);
    }
  }
  /// <summary>
  /// 獲取圖書列表(查)
  /// </summary>
  /// <param name="param">參數(shù)條件</param>
  /// <returns>圖書列表</returns>
  public List<BookInfo> GetBookInfoList(BookInfo param)
  {
    List<BookInfo> bookInfoList = new List<BookInfo>();
    string xPath = "bookstore/book"; //默認獲取所有圖書
    if (param.BookId != 0) //根據(jù)圖書ID查詢
    {
      xPath = String.Format("/bookstore/book[@id='{0}']", param.BookId);
    }
    else if (!String.IsNullOrEmpty(param.Category)) //根據(jù)圖書類別查詢
    {
      xPath = String.Format("/bookstore/book[@category='{0}']", param.Category);
    }
    else if (!String.IsNullOrEmpty(param.Title)) //根據(jù)圖書名稱查詢
    {
      xPath = String.Format("/bookstore/book[title='{0}']", param.Title);
    }
    XmlNodeList booksXmlNodeList = _booksXmlDoc.SelectNodes(xPath);
    foreach (XmlNode bookNode in booksXmlNodeList)
    {
      BookInfo bookInfo = new BookInfo();
      bookInfo.BookId = Convert.ToInt32(bookNode.Attributes["id"].Value); //獲取屬性值
      bookInfo.Category = bookNode.Attributes["category"].Value;
      bookInfo.Language = bookNode.SelectSingleNode("title").Attributes["lang"].Value; //獲取子節(jié)點的屬性值
      bookInfo.Title = bookNode.SelectSingleNode("title").InnerText;   //獲取元素值
      bookInfo.Author = bookNode.SelectSingleNode("author").InnerText;
      bookInfo.Year = bookNode.SelectSingleNode("year").InnerText;
      bookInfo.Price = Convert.ToDecimal(bookNode.SelectSingleNode("price").InnerText);
      bookInfoList.Add(bookInfo);
    }
    return bookInfoList;
  }
  /// <summary>
  /// 增加圖書信息（增）
  /// </summary>
  /// <param name="param"></param>
  /// <returns></returns>
  public bool AddBookInfo(BookInfo param)
  {
    bool result = false;
    XmlNode root = _booksXmlDoc.SelectSingleNode("bookstore"); //查找<bookstore>
    //創(chuàng)建節(jié)點
    XmlElement bookXmlElement = _booksXmlDoc.CreateElement("book");
    XmlElement titleXmlElement = _booksXmlDoc.CreateElement("title");
    XmlElement authorXmlElement = _booksXmlDoc.CreateElement("author");
    XmlElement yearXmlElement = _booksXmlDoc.CreateElement("year");
    XmlElement priceXmlElement = _booksXmlDoc.CreateElement("price");
    //給節(jié)點賦值
    bookXmlElement.SetAttribute("id", param.BookId.ToString());
    bookXmlElement.SetAttribute("category", param.Category);
    titleXmlElement.InnerText = param.Title; //給節(jié)點添加元素值
    titleXmlElement.SetAttribute("lang", param.Language);//給節(jié)點添加屬性值
    authorXmlElement.InnerText = param.Author;
    yearXmlElement.InnerText = param.Year;
    priceXmlElement.InnerText = param.Price.ToString();
    //AppendChild 將指定的節(jié)點添加到該節(jié)點的子節(jié)點列表的末尾
    bookXmlElement.AppendChild(titleXmlElement);
    bookXmlElement.AppendChild(authorXmlElement);
    bookXmlElement.AppendChild(yearXmlElement);
    bookXmlElement.AppendChild(priceXmlElement);
    root.AppendChild(bookXmlElement);
    _booksXmlDoc.Save(_basePath);
    result = true;
    return result;
  }
  /// <summary>
  /// 修改圖書信息（改）
  /// </summary>
  /// <param name="param"></param>
  /// <returns></returns>
  public bool EditBookInfo(BookInfo param)
  {
    bool result = false;
    if(param.BookId>0)
    {
      string xPath = String.Format("/bookstore/book[@id='{0}']", param.BookId);
      XmlNode editXmlNode = _booksXmlDoc.SelectSingleNode(xPath);
      XmlElement editXmlElement = (XmlElement)editXmlNode;
      if (editXmlElement != null)
      {
        editXmlElement.Attributes["category"].Value = param.Category;
        editXmlElement.SelectSingleNode("title").Attributes["lang"].Value = param.Language;
        editXmlElement.SelectSingleNode("title").InnerText = param.Title;
        editXmlElement.SelectSingleNode("author").InnerText = param.Author;
        editXmlElement.SelectSingleNode("year").InnerText = param.Year;
        editXmlElement.SelectSingleNode("price").InnerText = param.Price.ToString();
        _booksXmlDoc.Save(_basePath);
        result = true;
      }
    }
    return result;
  }
  /// <summary>
  /// 刪除圖書信息（刪）
  /// </summary>
  /// <param name="param"></param>
  /// <returns></returns>
  public bool DeleteBookInfo(BookInfo param)
  {
    bool result = false;
    if (param.BookId > 0)
    {
      string xPath = String.Format("/bookstore/book[@id='{0}']", param.BookId);
      XmlNode delXmlNode = _booksXmlDoc.SelectSingleNode(xPath);
      if (delXmlNode != null)
      {
        _booksXmlDoc.SelectSingleNode("bookstore").RemoveChild(delXmlNode);  //移除指定的子節(jié)點
        _booksXmlDoc.Save(_basePath);
        result = true;
      }
    }
    return result;
  }
}