以下是代码：
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Xml;
namespace WebApplication2
{
/// <summary>
/// XMLHelper XML文档操作管理器
/// </summary>
public class XMLHelper
{
public XMLHelper()
{
//
// TODO: 在此处添加构造函数逻辑
//
}
#region XML文档节点查询和读取
/// <summary>
/// 选择匹配XPath表达式的第一个节点XmlNode.
/// </summary>
/// <param name="xmlFileName">XML文档完全文件名(包含物理路径)</param>
/// <param name="xpath">要匹配的XPath表达式(例如:"//节点名//子节点名")</param>
/// <returns>返回XmlNode</returns>
public static XmlNode GetXmlNodeByXpath(string xmlFileName, string xpath)
{
XmlDocument xmlDoc = new XmlDocument();
try
{
xmlDoc.Load(xmlFileName); //加载XML文档
XmlNode xmlNode = xmlDoc.SelectSingleNode(xpath);
return xmlNode;
}
catch (Exception ex)
{
return null;
//throw ex; //这里可以定义你自己的异常处理
}
}
/// <summary>
/// 选择匹配XPath表达式的节点列表XmlNodeList.
/// </summary>
/// <param name="xmlFileName">XML文档完全文件名(包含物理路径)</param>
/// <param name="xpath">要匹配的XPath表达式(例如:"//节点名//子节点名")</param>
/// <returns>返回XmlNodeList</returns>
public static XmlNodeList GetXmlNodeListByXpath(string xmlFileName, string xpath)
{
XmlDocument xmlDoc = new XmlDocument();
try
{
xmlDoc.Load(xmlFileName); //加载XML文档
XmlNodeList xmlNodeList = xmlDoc.SelectNodes(xpath);
return xmlNodeList;
}
catch (Exception ex)
{
return null;
//throw ex; //这里可以定义你自己的异常处理
}
}
/// <summary>
/// 选择匹配XPath表达式的第一个节点的匹配xmlAttributeName的属性XmlAttribute.
/// </summary>
/// <param name="xmlFileName">XML文档完全文件名(包含物理路径)</param>
/// <param name="xpath">要匹配的XPath表达式(例如:"//节点名//子节点名</param>
/// <param name="xmlAttributeName">要匹配xmlAttributeName的属性名称</param>
/// <returns>返回xmlAttributeName</returns>
public static XmlAttribute GetXmlAttribute(string xmlFileName, string xpath, string xmlAttributeName)
{
string content = string.Empty;
XmlDocument xmlDoc = new XmlDocument();
XmlAttribute xmlAttribute = null;
try
{
xmlDoc.Load(xmlFileName); //加载XML文档
XmlNode xmlNode = xmlDoc.SelectSingleNode(xpath);
if (xmlNode != null)
{
if (xmlNode.Attributes.Count > 0)
{
xmlAttribute = xmlNode.Attributes[xmlAttributeName];
}
}
}
catch (Exception ex)
{
throw ex; //这里可以定义你自己的异常处理
}
return xmlAttribute;
}
#endregion
#region XML文档创建和节点或属性的添加、修改
/// <summary>
/// 创建一个XML文档
/// </summary>
/// <param name="xmlFileName">XML文档完全文件名(包含物理路径)</param>
/// <param name="rootNodeName">XML文档根节点名称(须指定一个根节点名称)</param>
/// <param name="version">XML文档版本号(必须为:"1.0")</param>
/// <param name="encoding">XML文档编码方式</param>
/// <param name="standalone">该值必须是"yes"或"no",如果为null,Save方法不在XML声明上写出独立属性</param>
/// <returns>成功返回true,失败返回false</returns>
public static bool CreateXmlDocument(string xmlFileName, string rootNodeName, string version, string encoding, string standalone)
{
bool isSuccess = false;
try
{
XmlDocument xmlDoc = new XmlDocument();
XmlDeclaration xmlDeclaration = xmlDoc.CreateXmlDeclaration(version, encoding, standalone);
XmlNode root = xmlDoc.CreateElement(rootNodeName);
xmlDoc.AppendChild(xmlDeclaration);
xmlDoc.AppendChild(root);
xmlDoc.Save(xmlFileName);
isSuccess = true;
}
catch (Exception ex)
{
throw ex; //这里可以定义你自己的异常处理
}
return isSuccess;
}
/// <summary>
/// 依据匹配XPath表达式的第一个节点来创建它的子节点(如果此节点已存在则追加一个新的同名节点
/// </summary>
/// <param name="xmlFileName">XML文档完全文件名(包含物理路径)</param>
/// <param name="xpath">要匹配的XPath表达式(例如:"//节点名//子节点名</param>
/// <param name="xmlNodeName">要匹配xmlNodeName的节点名称</param>
/// <param name="innerText">节点文本值</param>
/// <param name="xmlAttributeName">要匹配xmlAttributeName的属性名称</param>
/// <param name="value">属性值</param>
/// <returns>成功返回true,失败返回false</returns>
public static bool CreateXmlNodeByXPath(string xmlFileName, string xpath, string xmlNodeName, string innerText, string xmlAttributeName, string value)
{
bool isSuccess = false;
XmlDocument xmlDoc = new XmlDocument();
try
{
xmlDoc.Load(xmlFileName); //加载XML文档
XmlNode xmlNode = xmlDoc.SelectSingleNode(xpath);
if (xmlNode != null)
{
//存不存在此节点都创建
XmlElement subElement = xmlDoc.CreateElement(xmlNodeName);
subElement.InnerXml = innerText;
//如果属性和值参数都不为空则在此新节点上新增属性
if (!string.IsNullOrEmpty(xmlAttributeName) && !string.IsNullOrEmpty(value))
{
XmlAttribute xmlAttribute = xmlDoc.CreateAttribute(xmlAttributeName);
xmlAttribute.Value = value;
subElement.Attributes.Append(xmlAttribute);
}
xmlNode.AppendChild(subElement);
}
xmlDoc.Save(xmlFileName); //保存到XML文档
isSuccess = true;
}
catch (Exception ex)
{
throw ex; //这里可以定义你自己的异常处理
}
return isSuccess;
}
/// <summary>
/// 依据匹配XPath表达式的第一个节点来创建或更新它的子节点(如果节点存在则更新,不存在则创建)
/// </summary>
/// <param name="xmlFileName">XML文档完全文件名(包含物理路径)</param>
/// <param name="xpath">要匹配的XPath表达式(例如:"//节点名//子节点名</param>
/// <param name="xmlNodeName">要匹配xmlNodeName的节点名称</param>
/// <param name="innerText">节点文本值</param>
/// <returns>成功返回true,失败返回false</returns>
public static bool CreateOrUpdateXmlNodeByXPath(string xmlFileName, string xpath, string xmlNodeName, string innerText)
{
bool isSuccess = false;
bool isExistsNode = false;//标识节点是否存在
XmlDocument xmlDoc = new XmlDocument();
try
{
xmlDoc.Load(xmlFileName); //加载XML文档
XmlNode xmlNode = xmlDoc.SelectSingleNode(xpath);
if (xmlNode != null)
{
//遍历xpath节点下的所有子节点
foreach (XmlNode node in xmlNode.ChildNodes)
{
if (node.Name.ToLower() == xmlNodeName.ToLower())
{
//存在此节点则更新
node.InnerXml = innerText;
isExistsNode = true;
break;
}
}
if (!isExistsNode)
{
//不存在此节点则创建
XmlElement subElement = xmlDoc.CreateElement(xmlNodeName);
subElement.InnerXml = innerText;
xmlNode.AppendChild(subElement);
}
}
xmlDoc.Save(xmlFileName); //保存到XML文档
isSuccess = true;
}
catch (Exception ex)
{
throw ex; //这里可以定义你自己的异常处理
}
return isSuccess;
}
/// <summary>
/// 依据匹配XPath表达式的第一个节点来创建或更新它的属性(如果属性存在则更新,不存在则创建)
/// </summary>
/// <param name="xmlFileName">XML文档完全文件名(包含物理路径)</param>
/// <param name="xpath">要匹配的XPath表达式(例如:"//节点名//子节点名</param>
/// <param name="xmlAttributeName">要匹配xmlAttributeName的属性名称</param>
/// <param name="value">属性值</param>
/// <returns>成功返回true,失败返回false</returns>
public static bool CreateOrUpdateXmlAttributeByXPath(string xmlFileName, string xpath, string xmlAttributeName, string value)
{
bool isSuccess = false;
bool isExistsAttribute = false;//标识属性是否存在
XmlDocument xmlDoc = new XmlDocument();
try
{
xmlDoc.Load(xmlFileName); //加载XML文档
XmlNode xmlNode = xmlDoc.SelectSingleNode(xpath);
if (xmlNode != null)
{
//遍历xpath节点中的所有属性
foreach (XmlAttribute attribute in xmlNode.Attributes)
{
if (attribute.Name.ToLower() == xmlAttributeName.ToLower())
{
//节点中存在此属性则更新
attribute.Value = value;
isExistsAttribute = true;
break;
}
}
if (!isExistsAttribute)
{
//节点中不存在此属性则创建
XmlAttribute xmlAttribute = xmlDoc.CreateAttribute(xmlAttributeName);
xmlAttribute.Value = value;
xmlNode.Attributes.Append(xmlAttribute);
}
}
xmlDoc.Save(xmlFileName); //保存到XML文档
isSuccess = true;
}
catch (Exception ex)
{
throw ex; //这里可以定义你自己的异常处理
}
return isSuccess;
}
#endregion
#region XML文档节点或属性的删除
/// <summary>
/// 删除匹配XPath表达式的第一个节点(节点中的子元素同时会被删除)
/// </summary>
/// <param name="xmlFileName">XML文档完全文件名(包含物理路径)</param>
/// <param name="xpath">要匹配的XPath表达式(例如:"//节点名//子节点名</param>
/// <returns>成功返回true,失败返回false</returns>
public static bool DeleteXmlNodeByXPath(string xmlFileName, string xpath)
{
bool isSuccess = false;
XmlDocument xmlDoc = new XmlDocument();
try
{
xmlDoc.Load(xmlFileName); //加载XML文档
XmlNode xmlNode = xmlDoc.SelectSingleNode(xpath);
if (xmlNode != null)
{
//删除节点
xmlNode.ParentNode.RemoveChild(xmlNode);
}
xmlDoc.Save(xmlFileName); //保存到XML文档
isSuccess = true;
}
catch (Exception ex)
{
throw ex; //这里可以定义你自己的异常处理
}
return isSuccess;
}
/// <summary>
/// 删除匹配XPath表达式的第一个节点中的匹配参数xmlAttributeName的属性
/// </summary>
/// <param name="xmlFileName">XML文档完全文件名(包含物理路径)</param>
/// <param name="xpath">要匹配的XPath表达式(例如:"//节点名//子节点名</param>
/// <param name="xmlAttributeName">要删除的xmlAttributeName的属性名称</param>
/// <returns>成功返回true,失败返回false</returns>
public static bool DeleteXmlAttributeByXPath(string xmlFileName, string xpath, string xmlAttributeName)
{
bool isSuccess = false;
bool isExistsAttribute = false;
XmlDocument xmlDoc = new XmlDocument();
try
{
xmlDoc.Load(xmlFileName); //加载XML文档
XmlNode xmlNode = xmlDoc.SelectSingleNode(xpath);
XmlAttribute xmlAttribute = null;
if (xmlNode != null)
{
//遍历xpath节点中的所有属性
foreach (XmlAttribute attribute in xmlNode.Attributes)
{
if (attribute.Name.ToLower() == xmlAttributeName.ToLower())
{
//节点中存在此属性
xmlAttribute = attribute;
isExistsAttribute = true;
break;
}
}
if (isExistsAttribute)
{
//删除节点中的属性
xmlNode.Attributes.Remove(xmlAttribute);
}
}
xmlDoc.Save(xmlFileName); //保存到XML文档
isSuccess = true;
}
catch (Exception ex)
{
throw ex; //这里可以定义你自己的异常处理
}
return isSuccess;
}
/// <summary>
/// 删除匹配XPath表达式的第一个节点中的所有属性
/// </summary>
/// <param name="xmlFileName">XML文档完全文件名(包含物理路径)</param>
/// <param name="xpath">要匹配的XPath表达式(例如:"//节点名//子节点名</param>
/// <returns>成功返回true,失败返回false</returns>
public static bool DeleteAllXmlAttributeByXPath(string xmlFileName, string xpath)
{
bool isSuccess = false;
XmlDocument xmlDoc = new XmlDocument();
try
{
xmlDoc.Load(xmlFileName); //加载XML文档
XmlNode xmlNode = xmlDoc.SelectSingleNode(xpath);
if (xmlNode != null)
{
//遍历xpath节点中的所有属性
xmlNode.Attributes.RemoveAll();
}
xmlDoc.Save(xmlFileName); //保存到XML文档
isSuccess = true;
}
catch (Exception ex)
{
throw ex; //这里可以定义你自己的异常处理
}
return isSuccess;
}
#endregion
}
}
创建XML文档
//这是XML文档根节点名
string rootNodeName = "books";
//这是XML文档物理文件名（包含物理路径）
string xmlFileName = Application.StartupPath + @"\book.xml";
XMLHelper.CreateXmlDocument(xmlFileName, rootNodeName, "1.0", "utf-8", null);
MessageBox.Show("XML文档创建成功:" + xmlFileName);
向XML文档中添加一个新节点
string xmlFileName = Application.StartupPath + @"\book.xml";
string xpath = "/books"; //这是新节点的父节点路径
string nodename = "book"; //这是新节点名称,在父节点下新增
string nodetext = "这是新节点中的文本值";
bool isSuccess = XMLHelper.CreateOrUpdateXmlNodeByXPath(xmlFileName, xpath, nodename, nodetext);
MessageBox.Show("XML节点添加或更新成功:" + isSuccess.ToString());
向XML文档中的子节点中新增或修改（如果存在则修改）一个子节点,比如name,author,date节点等：
string xmlFileName = Application.StartupPath + @"\book.xml";
string xpath = "/books/book"; //这是新子节点的父节点路径
string nodename = "name"; //这是新子节点名称,在父节点下新增
string nodetext = "我的世界我的梦";
bool isSuccess = XMLHelper.CreateOrUpdateXmlNodeByXPath(xmlFileName, xpath, nodename, nodetext);
MessageBox.Show("XML节点添加或更新成功:" + isSuccess.ToString());
string xmlFileName = Application.StartupPath + @"\book.xml";
string xpath = "/books/book"; //要新增属性的节点
string attributeName = "id"; //新属性名称,ISDN号也是这么新增的
string attributeValue = "1"; //新属性值
bool isSuccess = XMLHelper.CreateOrUpdateXmlAttributeByXPath(xmlFileName, xpath, attributeName, attributeValue);
MessageBox.Show("XML属性添加或更新成功:" + isSuccess.ToString());
string xmlFileName = Application.StartupPath + @"\book.xml";
string xpath = "/books/book[@id='1']"; //要删除的id为1的book子节点
bool isSuccess = XMLHelper.DeleteXmlNodeByXPath(xmlFileName, xpath);
MessageBox.Show("XML节点删除成功:" + isSuccess.ToString());
string xmlFileName = Application.StartupPath + @"\book.xml";
//删除id为2的book子节点中的ISDN属性
string xpath = "/books/book[@id='2']";
string attributeName = "ISDN";
bool isSuccess = XMLHelper.DeleteXmlAttributeByXPath(xmlFileName, xpath, attributeName);
MessageBox.Show("XML属性删除成功:" + isSuccess.ToString());
string xmlFileName = Application.StartupPath + @"\book.xml";
//要读的id为1的book子节点
string xpath = "/books/book[@id='1']";
XmlNodeList nodeList = XMLHelper.GetXmlNodeListByXpath(xmlFileName, xpath);
string strAllNode = "";
//遍历节点中所有的子节点
foreach (XmlNode node in nodeList)
{
strAllNode += "\n name:" + node.Name + " InnerText:" + node.InnerText;
}
MessageBox.Show("XML节点中所有子节点有:" + strAllNode);
源码下载：/Files/lixyvip/XmlHelper.rar
最后，强烈鄙视贴源码，不在下方提供源码下载，却在源码中加“显示代码行数”的博友，强烈鄙视！！！
原文转自：http://www.cnblogs.com/chnboy/archive/2009/04/02/1427652.html