根据XPath找到某一个特定的节点 Anny

工作中需要解析到XML文件，发现XPath很神奇。如果能灵活设置XPath，找到某个特定的节点就可以轻而易举了。

下面的链接大家可以参考一下，主要就是介绍XPath的。

来自MSDN的介绍：http://msdn.microsoft.com/en-us/library/ms256086.aspx

便于大家理解，还可以看看下边的两个链接：

http://www.zvon.org/xxl/XPathTutorial/Output/examples.html

http://www.w3schools.com/xpath/xpath_syntax.asp

下面的代码是以后需要继续维护的XmlHelper类，先放到这里。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;

namespace XmlHelper
{
    class XmlHelper
    {
        public static void CreateXML(string xml,string fileName)
        {
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.LoadXml(xml);
            xmlDoc.Save(fileName);
        }

        public static void CreateXML(string fileName, string node, string version, string encoding, string standalone)
        {
            XmlDocument xmlDoc = new XmlDocument();
            XmlDeclaration xmlDeclaration = xmlDoc.CreateXmlDeclaration(version, encoding, standalone);
            xmlDoc.AppendChild(xmlDeclaration);
           
            XmlNode root = xmlDoc.CreateElement(node);           
            xmlDoc.AppendChild(root);

            xmlDoc.Save(fileName);
        }

        public static void CreateXML(string fileName,XmlNode node,string version, string encoding, string standalone )
        {
            XmlDocument xmlDoc = new XmlDocument();
            XmlDeclaration xmlDeclaration = xmlDoc.CreateXmlDeclaration(version, encoding, standalone);
            xmlDoc.AppendChild(xmlDeclaration);
            xmlDoc.AppendChild(node);
            xmlDoc.Save(fileName);
        }

        /// <summary>
        /// Find xml by xpath according to subelement value
        /// </summary>
        /// <param name="xml"></param>
        /// <param name="xPath">/students/student/name["may"]</param>
        /// <returns></returns>
        public static string FindNodeXmlByXPathWithSubElementValue(string fileName, string xPath)
        {
            string outerXml = string.Empty;
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load(fileName);
            XmlNode node = xmlDoc.SelectSingleNode(xPath);
            outerXml = node.OuterXml;
            return outerXml;
        }

        /// <summary>
        /// Find specified node by xpath according to subelement value
        /// </summary>
        /// <param name="xml"></param>
        /// <param name="xPath">/students/student/name["may"]</param>
        /// <returns></returns>
        public static XmlNode FindNodeByXPathWithSubElementValue(string fileName, string xPath)
        {           
            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load(fileName);
            XmlNode node = xmlDoc.SelectSingleNode(xPath);
            return node;
            
        }
    }
}