转自：http://www.cnblogs.com/pengze0902/p/5947997.html
在.net的项目开发中，经常会对XML文件进行操作，由于XML文件可以实现跨平台传输，较多的应用在数据传输中，特总结以下几种常用的XML操作方法：
1.创建XML文档：
/// <summary>
/// 创建XML文档
/// </summary>
/// <param name="name">根节点名称</param>
/// <param name="type">根节点的一个属性值</param>
/// <returns>XmlDocument对象</returns>
public static XmlDocument CreateXmlDocument(string name, string type)
{
XmlDocument doc;
try
{
doc = new XmlDocument();
doc.LoadXml("<" + name + "/>");
var rootEle = doc.DocumentElement;
rootEle?.SetAttribute("type", type);
}
catch (Exception er)
{
throw new Exception(er.ToString());
}
return doc;
}
2.读取XML文档中的数据：
/// <summary>
/// 读取数据
/// </summary>
/// <param name="path">路径</param>
/// <param name="node">节点</param>
/// <param name="attribute">属性名，非空时返回该属性值，否则返回串联值</param>
/// <returns>string</returns>
public static string Read(string path, string node, string attribute)
{
var value = "";
try
{
var doc = new XmlDocument();
doc.Load(path);
var xn = doc.SelectSingleNode(node);
if (xn != null && xn.Attributes != null)
value = (attribute.Equals("") ? xn.InnerText : xn.Attributes[attribute].Value);
}
catch (Exception er)
{
throw new Exception(er.ToString());
}
return value;
}
3.对XML文档插入数据：
/// <summary>
/// 插入数据
/// </summary>
/// <param name="path">路径</param>
/// <param name="node">节点</param>
/// <param name="element">元素名，非空时插入新元素，否则在该元素中插入属性</param>
/// <param name="attribute">属性名，非空时插入该元素属性值，否则插入元素值</param>
/// <param name="value">值</param>
/// <returns></returns>
public static void Insert(string path, string node, string element, string attribute, string value)
{
try
{
var doc = new XmlDocument();
doc.Load(path);
var xn = doc.SelectSingleNode(node);
if (element.Equals(""))
{
if (!attribute.Equals(""))
{
var xe = (XmlElement)xn;
xe?.SetAttribute(attribute, value);
//xe?.SetAttribute(attribute, value);
}
}
else
{
var xe = doc.CreateElement(element);
if (attribute.Equals(""))
xe.InnerText = value;
else
xe.SetAttribute(attribute, value);
xn?.AppendChild(xe);
}
doc.Save(path);
}
catch (Exception er)
{
throw new Exception(er.ToString());
}
}
4.修改XML文档中的数据：
/// <summary>
/// 修改数据
/// </summary>
/// <param name="path">路径</param>
/// <param name="node">节点</param>
/// <param name="attribute">属性名，非空时修改该节点属性值，否则修改节点值</param>
/// <param name="value">值</param>
/// <returns></returns>
public static void Update(string path, string node, string attribute, string value)
{
try
{
var doc = new XmlDocument();
doc.Load(path);
var xn = doc.SelectSingleNode(node);
var xe = (XmlElement)xn;
if (attribute.Equals(""))
{
if (xe != null) xe.InnerText = value;
}
else
{
xe?.SetAttribute(attribute, value);
}
doc.Save(path);
}
catch (Exception er)
{
throw new Exception(er.ToString());
}
}
5.删除XML文档中数据：
/// <summary>
/// 删除数据
/// </summary>
/// <param name="path">路径</param>
/// <param name="node">节点</param>
/// <param name="attribute">属性名，非空时删除该节点属性值，否则删除节点值</param>
/// <returns></returns>
public static void Delete(string path, string node, string attribute)
{
try
{
var doc = new XmlDocument();
doc.Load(path);
var xn = doc.SelectSingleNode(node);
var xe = (XmlElement)xn;
if (attribute.Equals(""))
{
xn?.ParentNode?.RemoveChild(xn);
}
else
{
xe?.RemoveAttribute(attribute);
}
doc.Save(path);
}
catch (Exception er)
{
throw new Exception(er.ToString());
}
}
6.读取XML文档中指定节点数据：
/// <summary>
/// 获得xml文件中指定节点的节点数据
/// </summary>
/// <param name="path"></param>
/// <param name="nodeName"></param>
/// <returns></returns>
public static string GetNodeInfoByNodeName(string path, string nodeName)
{
var xmlString = string.Empty;
try
{
var xml = new XmlDocument();
xml.Load(path);
var root = xml.DocumentElement;
if (root == null) return xmlString;
var node = root.SelectSingleNode("//" + nodeName);
if (node != null)
{
xmlString = node.InnerText;
}
}
catch (Exception er)
{
throw new Exception(er.ToString());
}
return xmlString;
}
7.获取XML指定节点的属性：
/// <summary>
/// 功能:读取指定节点的指定属性值
/// </summary>
/// <param name="path"></param>
/// <param name="strNode">节点名称</param>
/// <param name="strAttribute">此节点的属性</param>
/// <returns></returns>
public string GetXmlNodeAttributeValue(string path, string strNode, string strAttribute)
{
var strReturn = "";
try
{
var xml = new XmlDocument();
xml.Load(path);
//根据指定路径获取节点
var xmlNode = xml.SelectSingleNode(strNode);
if (xmlNode != null)
{
//获取节点的属性，并循环取出需要的属性值
var xmlAttr = xmlNode.Attributes;
if (xmlAttr == null) return strReturn;
for (var i = 0; i < xmlAttr.Count; i++)
{
if (xmlAttr.Item(i).Name != strAttribute) continue;
strReturn = xmlAttr.Item(i).Value;
break;
}
}
}
catch (XmlException xmle)
{
throw new Exception(xmle.Message);
}
return strReturn;
}
8.设置XML文档中指定节点的属性：
/// <summary>
/// 功能:设置节点的属性值
/// </summary>
/// <param name="path"></param>
/// <param name="xmlNodePath">节点名称</param>
/// <param name="xmlNodeAttribute">属性名称</param>
/// <param name="xmlNodeAttributeValue">属性值</param>
public void SetXmlNodeAttributeValue(string path, string xmlNodePath, string xmlNodeAttribute, string xmlNodeAttributeValue)
{
try
{
var xml = new XmlDocument();
xml.Load(path);
//可以批量为符合条件的节点的属性付值
var xmlNode = xml.SelectNodes(xmlNodePath);
if (xmlNode == null) return;
foreach (var xmlAttr in from XmlNode xn in xmlNode select xn.Attributes)
{
if (xmlAttr == null) return;
for (var i = 0; i < xmlAttr.Count; i++)
{
if (xmlAttr.Item(i).Name != xmlNodeAttribute) continue;
xmlAttr.Item(i).Value = xmlNodeAttributeValue;
break;
}
}
}
catch (XmlException xmle)
{
throw new Exception(xmle.Message);
}
}
9.读取XML文档指定节点的值：
/// <summary>
/// 读取XML资源中的指定节点内容
/// </summary>
/// <param name="source">XML资源</param>
/// <param name="xmlType">XML资源类型：文件，字符串</param>
/// <param name="nodeName">节点名称</param>
/// <returns>节点内容</returns>
public static object GetNodeValue(string source, XmlType xmlType, string nodeName)
{
var xd = new XmlDocument();
if (xmlType == XmlType.File)
{
xd.Load(source);
}
else
{
xd.LoadXml(source);
}
var xe = xd.DocumentElement;
XmlNode xn = null;
if (xe != null)
{
xn= xe.SelectSingleNode("//" + nodeName);
}
return xn.InnerText;
}
10.更新XML文档指定节点的内容：
/// <summary>
/// 更新XML文件中的指定节点内容
/// </summary>
/// <param name="filePath">文件路径</param>
/// <param name="nodeName">节点名称</param>
/// <param name="nodeValue">更新内容</param>
/// <returns>更新是否成功</returns>
public static bool UpdateNode(string filePath, string nodeName, string nodeValue)
{
try
{
bool flag;
var xd = new XmlDocument();
xd.Load(filePath);
var xe = xd.DocumentElement;
if (xe == null) return false;
var xn = xe.SelectSingleNode("//" + nodeName);
if (xn != null)
{
xn.InnerText = nodeValue;
flag = true;
}
else
{
flag = false;
}
return flag;
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}
11.将对象转化为XML文件，并存入指定目录：
/// <summary>
/// 将对象转化为xml，并写入指定路径的xml文件中
/// </summary>
/// <typeparam name="T">C#对象名</typeparam>
/// <param name="item">对象实例</param>
/// <param name="path">路径</param>
/// <param name="jjdbh">标号</param>
/// <param name="ends">结束符号（整个xml的路径类似如下：C:xmltest201111send.xml，其中path=C:xmltest,jjdbh=201111,ends=send）</param>
/// <returns></returns>
public static string WriteXml<T>(T item, string path, string jjdbh, string ends)
{
if (string.IsNullOrEmpty(ends))
{
//默认为发送
ends = "send";
}
//控制写入文件的次数
var i = 0;
//获取当前对象的类型，也可以使用反射typeof(对象名)
var serializer = new XmlSerializer(item.GetType());
//xml的路径组合
object[] obj = { path, "\", jjdbh, ends, ".xml" };
var xmlPath = string.Concat(obj);
while (true)
{
try
{
//用filestream方式创建文件不会出现“文件正在占用中，用File.create”则不行
var fs = System.IO.File.Create(xmlPath);
fs.Close();
TextWriter writer = new StreamWriter(xmlPath, false, Encoding.UTF8);
var xml = new XmlSerializerNamespaces();
xml.Add(string.Empty, string.Empty);
serializer.Serialize(writer, item, xml);
writer.Flush();
writer.Close();
break;
}
catch (Exception)
{
if (i < 5)
{
i++;
continue;
}
break;
}
}
return SerializeToXmlStr<T>(item, true);
}
12.向一个已经存在的父节点中插入一个子节点：
/// <summary>
/// 向一个已经存在的父节点中插入一个子节点
/// </summary>
/// <param name="path"></param>
/// <param name="parentNodePath">父节点</param>
/// <param name="childnodename">子节点名称</param>
public void AddChildNode(string path, string parentNodePath, string childnodename)
{
try
{
var xml = new XmlDocument();
xml.Load(path);
var parentXmlNode = xml.SelectSingleNode(parentNodePath);
XmlNode childXmlNode = xml.CreateElement(childnodename);
if ((parentXmlNode) != null)
{
//如果此节点存在
parentXmlNode.AppendChild(childXmlNode);
}
else
{
//如果不存在就放父节点添加
GetXmlRoot(path).AppendChild(childXmlNode);
}
}
catch (XmlException xmle)
{
throw new Exception(xmle.Message);
}
}
以上的方法总结采用.net4.5版本和c#6.0语法