LINQ to XML实现XML文档的增删改查

<?xml version="1.0" encoding="utf-8"?>
<bookstore>
<book id="1" category="CHILDREN">
<title>Harry Potter</title>
<author>J K. Rowling</author>
<publishDate>2005-08-15</publishDate>
<price>29.99</price>
</book>
<book id="2" category="WEB">
<title>Learning XML</title>
<author>Erik T. Ray</author>
<publishDate>2003-10-18</publishDate>
<price>39.95</price>
</book>
<book id="3" category="WEB">
<title>XQuery Kick Start</title>
<author>James McGovern</author>
<publishDate>2005-06-25</publishDate>
<price>49.99</price>
</book>
</bookstore>

/// <summary>
/// 图书信息实体类
/// </summary>
public class BookInfo
{
public int BookId { set; get; }             //图书ID
public string Title { set; get; }           //图书名称
public string Category { set; get; }        //图书分类
public string Author { set; get; }          //图书作者
public DateTime PublishDate { set; get; }   //出版时间
public Double Price { set; get; }           //销售价格
}

using System.Linq;
using System.Xml.Linq;

public class BookInfoBLL
{
private string _basePath = AppDomain.CurrentDomain.SetupInformation.ApplicationBase + @"/xml/Books.xml";  //XML文件路径

/// <summary>
/// 创建图书XML文档（创建）
/// </summary>
public void CreateBookXml()
{
//获取图书列表
List<BookInfo> bookList = GetBookList();
//创建XML文档
XDocument bookDoc = new XDocument();
//创建声明对象
XDeclaration xDeclaration = new XDeclaration("1.0", "utf-8", "yes");
bookDoc.Declaration = xDeclaration;    //指定XML声明对象
//创建bookstore节点
XElement xElement = new XElement("bookstore");
foreach (BookInfo book in bookList)
{
//创建book节点
XElement bookXml = new XElement("book");
//添加属性
bookXml.Add(new XAttribute("id", book.BookId));
bookXml.Add(new XAttribute("category", book.Category));
//添加子节点
bookXml.Add(new XElement("title", book.Title));
bookXml.Add(new XElement("author", book.Author));
bookXml.Add(new XElement("publishDate", book.PublishDate.ToString("yyyy-MM-dd")));
bookXml.Add(new XElement("price", book.Price));
//将book节点添加到bookstore节点中
xElement.Add(bookXml);
}
//保存文件
bookDoc.Add(xElement);
bookDoc.Save(_basePath);
}

/// <summary>
/// 获取图书列表(查询)
/// </summary>
/// <param name="param">参数条件</param>
/// <returns>图书列表</returns>
public List<BookInfo> GetBookInfoList(BookInfo param)
{
List<BookInfo> bookList = new List<BookInfo>();
XElement xml = XElement.Load(_basePath);

var bookVar = xml.Descendants("book");   //默认查询所有图书
if (param.BookId != 0) //根据图书ID查询
{
bookVar = xml.Descendants("book").Where(a => a.Attribute("id").Value == param.BookId.ToString());
}
else if (!String.IsNullOrEmpty(param.Category)) //根据图书类别查询
{
bookVar = xml.Descendants("book").Where(a => a.Attribute("category").Value == param.Category);
}
else if (!String.IsNullOrEmpty(param.Title)) //根据图书名称查询
{
bookVar = xml.Descendants("book").Where(a => a.Element("title").Value == param.Title);
}

bookList = (from book in bookVar
select new BookInfo
{
BookId = int.Parse(book.Attribute("id").Value),
Category = book.Attribute("category").Value,
Title = book.Element("title").Value,
Author = book.Element("author").Value,
PublishDate = DateTime.Parse(book.Element("publishDate").Value),
Price = double.Parse(book.Element("price").Value)
}).ToList();
return bookList;
}

/// <summary>
/// 增加图书信息（新增）
/// </summary>
/// <param name="param"></param>
/// <returns></returns>
public bool AddBookInfo(BookInfo param)
{
XElement xml = XElement.Load(_basePath);
//创建book节点
XElement bookXml = new XElement("book");
//添加属性
bookXml.Add(new XAttribute("id", param.BookId));
bookXml.Add(new XAttribute("category", param.Category));
//添加子节点
bookXml.Add(new XElement("title", param.Title));
bookXml.Add(new XElement("author", param.Author));
bookXml.Add(new XElement("publishDate", param.PublishDate.ToString("yyyy-MM-dd")));
bookXml.Add(new XElement("price", param.Price));
xml.Add(bookXml);
//保存
xml.Save(_basePath);
return true;
}

/// <summary>
/// 修改图书信息（修改）
/// </summary>
/// <param name="param"></param>
/// <returns></returns>
public bool EditBookInfo(BookInfo param)
{
bool result = false;
if (param.BookId > 0)
{
//根据BookId找到要修改的图书XML
XElement xml = XElement.Load(_basePath);
XElement bookXml = (from db in xml.Descendants("book") where db.Attribute("id").Value == param.BookId.ToString() select db).Single();
//修改属性
bookXml.SetAttributeValue("category", param.Category);
//修改子节点
bookXml.SetElementValue("title", param.Title);
bookXml.SetElementValue("author", param.Author);
bookXml.SetElementValue("publishDate", param.PublishDate.ToString("yyyy-MM-dd"));
bookXml.SetElementValue("price", param.Price);
//保存
xml.Save(_basePath);
result = true;
}
return result;
}

/// <summary>
/// 删除图书信息（删除）
/// </summary>
/// <param name="param"></param>
/// <returns></returns>
public bool DeleteBookInfo(BookInfo param)
{
bool result = false;
if (param.BookId > 0)
{
//根据BookId找到要删除的图书XML
XElement xml = XElement.Load(_basePath);
XElement bookXml = (from db in xml.Descendants("book") where db.Attribute("id").Value == param.BookId.ToString() select db).Single();
bookXml.Remove();
//保存
xml.Save(_basePath);
result = true;
}
return result;
}

/// <summary>
/// 获取图书列表
/// </summary>
/// <returns></returns>
public List<BookInfo> GetBookList()
{
List<BookInfo> bookList = new List<BookInfo>();
//创建图书1
BookInfo book1 = new BookInfo() {
BookId = 1,
Category = "CHILDREN",
Title = "Harry Potter",
Author = "J K. Rowling",
PublishDate = new DateTime(2005,08,15),
Price = 29.99
};
bookList.Add(book1);
//创建图书2
BookInfo book2 = new BookInfo()
{
BookId = 2,
Category = "WEB",
Title = "Learning XML",
Author = "Erik T. Ray",
PublishDate = new DateTime(2003,10,18),
Price = 39.95
};
bookList.Add(book2);
//创建图书3
BookInfo book3 = new BookInfo()
{
BookId = 3,
Category = "WEB",
Title = "XQuery Kick Start",
Author = "James McGovern",
PublishDate = new DateTime(2005,6,25),
Price = 49.99
};
bookList.Add(book3);
return bookList;
}
}