c# xpath案例分析

在C#中，使用System.Xml.XPath命名空间可以方便地处理XPath表达式

假设我们有以下XML文档：

<?xml version="1.0" encoding="UTF-8"?> <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>   <book id="3">     <title>Book 3</title>     <author>Author 3</author>   </book> </books> 

现在，我们将使用C#和XPath表达式来查询此XML文档。

1. 选择所有书籍的标题：

using System; using System.Xml; using System.Xml.XPath;  class XPathExample {     static void Main()     {         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>             <book id='3'>               <title>Book 3</title>               <author>Author 3</author>             </book>           </books>";          XPathDocument doc = new XPathDocument(xml);         XPathNavigator navigator = doc.CreateNavigator();          XPathExpression expr = navigator.Compile("//title");         XPathNodeIterator iterator = expr.Select();          Console.WriteLine("Book titles:");         while (iterator.MoveNext())         {             Console.WriteLine(iterator.Current.Value);         }     } } 

输出：

Book titles: Book 1 Book 2 Book 3 

2. 根据书籍ID选择书籍：

using System; using System.Xml; using System.Xml.XPath;  class XPathExample {     static void Main()     {         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>             <book id='3'>               <title>Book 3</title>               <author>Author 3</author>             </book>           </books>";          XPathDocument doc = new XPathDocument(xml);         XPathNavigator navigator = doc.CreateNavigator();          XPathExpression expr = navigator.Compile("//book[@id='2']");         XPathNodeIterator iterator = expr.Select();          Console.WriteLine("Book with ID 2:");         while (iterator.MoveNext())         {             Console.WriteLine(iterator.Current.Value);         }     } } 

输出：

Book with ID 2: Book 2 Author 2 

这些示例展示了如何使用C#和XPath表达式查询XML文档。您可以根据需要修改这些示例以满足您的实际需求。