c#操作xml之三
上次，我们介绍了增加和删除xml的一些操作，这次我们将介绍如何更改和读取xml特定节点。我们依然以上次的xml文件为例：
<?
xml version="1.0" encoding="utf-8"
?>
<
phonebook
>
<
member
id
="6"
>
<
name
>
456
</
name
>
<
qq
>
5465
</
qq
>
</
member
>
<
member
id
="5"
>
<
name
>
jjjjj
</
name
>
<
qq
>
3456789
</
qq
>
</
member
>
</
phonebook
>
首先是更改操作，它也包含两个方面即更改指定节点的值和指定节点的某一属性值，我们可以使用的方法如下：
/**/
/// <summary>
/// 更新Xml节点内容 /// </summary> /// <param name="xmlPath">xml路径</param> /// <param name="Node">要更换内容的节点:节点路径 根节点/父节点/当前节点</param>
/// <param name="Content">新的内容</param>
public
static
void
XmlNodeReplace(
string
xmlPath,
string
Node,
string
Content)
{ XmlDocument objXmlDoc = new XmlDocument(); objXmlDoc.Load(xmlPath); objXmlDoc.SelectSingleNode(Node).InnerText = Content; objXmlDoc.Save(xmlPath); }
/**/
/// <summary> /// 更改节点的属性值 /// </summary> /// <param name="xmlPath">文件路径</param> /// <param name="NodePath">节点路径</param> /// <param name="NodeAttribute1">要更改的节点属性的名称</param> /// <param name="NodeAttributeText">更改的属性值</param>
public
static
void
XmlAttributeEide(
string
xmlPath,
string
NodePath,
string
NodeAttribute1,
string
NodeAttributeText)
{ XmlDocument objXmlDoc = new XmlDocument(); objXmlDoc.Load(xmlPath); XmlNode nodePath = objXmlDoc.SelectSingleNode(NodePath); XmlElement xe = (XmlElement)nodePath; xe.SetAttribute(NodeAttribute1, NodeAttributeText); objXmlDoc.Save(xmlPath); }
第一个方面，加入我们要更改menber（id=6）下节点name的值我们可以这样做：
string
xmlPath
=
Server.MapPath(
"
~/test.xml
"
); XmlHelper.XmlNodeReplace(xmlPath,
"
//member[@id=6]/name
"
,
"
hya
"
);
也可以
string
xmlPath
=
Server.MapPath(
"
~/test.xml
"
); XmlHelper.XmlNodeReplace(xmlPath,
"
//member[qq='5465']/name
"
,
"
hya
"
);
总之你能够用xpath语法找到所要更改的节点即可。
更改属性值也一样，在这不在赘述！
查询正如对数据库操作查询考查你对sql的熟练程度一样，对xml的查询也就是考查你对xpath了解多少。在这里我只是列出几个有限的调用方法，相信从上面的介绍中你可以大致对xpath有了一定的了解：
读取XML到DataSet
#region 读取XML到DataSet
/**//// <summary> /// 功能:读取XML到DataSet中 /// </summary> /// <param name="XmlPath">xml路径</param>
/// <returns>DataSet</returns> public static DataSet GetXml(string XmlPath) { DataSet ds = new DataSet(); ds.ReadXml(@XmlPath); return ds; } #endregion
读取xml文档并返回一个节点
#region 读取xml文档并返回一个节点 /**//// <summary> /// 读取xml文档并返回一个节点:适用于一级节点 /// </summary> /// <param name="XmlPath">xml路径</param> /// <param name="NodeName">节点</param> /// <returns></returns> public static string ReadXmlReturnNode(string XmlPath, string Node) { XmlDocument docXml = new XmlDocument(); docXml.Load(@XmlPath); XmlNodeList xn = docXml.GetElementsByTagName(Node); return xn.Item(0).InnerText.ToString(); } #endregion
查找数据,返回一个DataSet
#region 查找数据,返回一个DataSet /**//// <summary> /// 查找数据,返回当前节点的所有下级节点,填充到一个DataSet中 /// </summary> /// <param name="xmlPath">xml文档路径</param> /// <param name="XmlPathNode">节点的路径:根节点/父节点/当前节点</param> /// <returns></returns> public static DataSet GetXmlData(string xmlPath, string XmlPathNode) { XmlDocument objXmlDoc = new XmlDocument(); objXmlDoc.Load(xmlPath); DataSet ds = new DataSet(); StringReader read = new StringReader(objXmlDoc.SelectSingleNode(XmlPathNode).OuterXml); ds.ReadXml(read); return ds; } 读取指定节点的指定属性值#region 读取指定节点的指定属性值 /**//// <summary> /// 功能: /// 读取指定节点的指定属性值 /// </summary> /// <param name="strNode">节点路径</param> /// <param name="strAttribute">此节点的属性</param> /// <returns></returns> public string GetXmlNodeAttribute(string xmlPath, string strNode, string strAttribute) { string strReturn = ""; xmlDoc.Load(xmlPath); try { //根据指定路径获取节点 XmlNode xmlNode = xmlDoc.SelectSingleNode(strNode); //获取节点的属性，并循环取出需要的属性值 XmlAttributeCollection xmlAttr = xmlNode.Attributes; for (int i = 0; i < xmlAttr.Count; i++) { if (xmlAttr.Item(i).Name == strAttribute) strReturn = xmlAttr.Item(i).Value; } } catch (XmlException xmle) { throw xmle; } return strReturn; } #endregion 读取指定节点的值#region 读取指定节点的值 /**//// <summary> /// 功能: /// 读取指定节点的值 /// </summary> /// <param name="strNode">节点名称（xpath）</param> /// <returns></returns> public string GetXmlNodeValue(string xmlPath,string strNode) { string strReturn = String.Empty; xmlDoc.Load(xmlPath); try { //根据路径获取节点 XmlNode xmlNode = xmlDoc.SelectSingleNode(strNode); strReturn = xmlNode.InnerText; } catch (XmlException xmle) { System.Console.WriteLine(xmle.Message); } return strReturn; } #endregion 根据节点属性读取子节点值(较省资源模式)#region 根据节点属性读取子节点值(较省资源模式) /**//// <summary> /// 根据节点属性读取子节点值(较省资源模式) /// </summary> /// <param name="XmlPath">xml路径</param> /// <param name="FatherElement">父节点值</param> /// <param name="AttributeName">属性名称</param> /// <param name="AttributeValue">属性值</param> /// <param name="ArrayLength">返回的数组长度</param> /// <returns></returns> public static System.Collections.ArrayList GetSubElementByAttribute(string XmlPath, string FatherElement, string AttributeName, string AttributeValue, int ArrayLength) { System.Collections.ArrayList al = new System.Collections.ArrayList(); XmlDocument docXml = new XmlDocument(); docXml.Load(@XmlPath); XmlNodeList xn; xn = docXml.DocumentElement.SelectNodes("//" + FatherElement + "[" + @AttributeName + "='" + AttributeValue + "']"); XmlNodeList xx = xn.Item(0).ChildNodes; for (int i = 0; i < ArrayLength & i < xx.Count; i++) { al.Add(xx.Item(i).InnerText); } return al; } #endregion
#region 读取指定节点的指定属性值
/**//// <summary>
/// 功能:
/// 读取指定节点的指定属性值
/// </summary>
/// <param name="strNode">节点路径</param>
/// <param name="strAttribute">此节点的属性</param>
/// <returns></returns>
public string GetXmlNodeAttribute(string xmlPath, string strNode, string strAttribute)
{
string strReturn = "";
xmlDoc.Load(xmlPath);
try
{
//根据指定路径获取节点
XmlNode xmlNode = xmlDoc.SelectSingleNode(strNode);
//获取节点的属性，并循环取出需要的属性值
XmlAttributeCollection xmlAttr = xmlNode.Attributes;
for (int i = 0; i < xmlAttr.Count; i++)
{
if (xmlAttr.Item(i).Name == strAttribute)
strReturn = xmlAttr.Item(i).Value;
}
}
catch (XmlException xmle)
{
throw xmle;
}
return strReturn;
}
#endregion
读取指定节点的值#region 读取指定节点的值
/**//// <summary>
/// 功能:
/// 读取指定节点的值
/// </summary>
/// <param name="strNode">节点名称（xpath）</param>
/// <returns></returns>
public string GetXmlNodeValue(string xmlPath,string strNode)
{
string strReturn = String.Empty;
xmlDoc.Load(xmlPath);
try
{
//根据路径获取节点
XmlNode xmlNode = xmlDoc.SelectSingleNode(strNode);
strReturn = xmlNode.InnerText;
}
catch (XmlException xmle)
{
System.Console.WriteLine(xmle.Message);
}
return strReturn;
}
#endregion
根据节点属性读取子节点值(较省资源模式)#region 根据节点属性读取子节点值(较省资源模式)
/**//// <summary>
/// 根据节点属性读取子节点值(较省资源模式)
/// </summary>
/// <param name="XmlPath">xml路径</param>
/// <param name="FatherElement">父节点值</param>
/// <param name="AttributeName">属性名称</param>
/// <param name="AttributeValue">属性值</param>
/// <param name="ArrayLength">返回的数组长度</param>
/// <returns></returns>
public static System.Collections.ArrayList GetSubElementByAttribute(string XmlPath, string FatherElement, string AttributeName, string AttributeValue, int ArrayLength)
{
System.Collections.ArrayList al = new System.Collections.ArrayList();
XmlDocument docXml = new XmlDocument();
docXml.Load(@XmlPath);
XmlNodeList xn;
xn = docXml.DocumentElement.SelectNodes("//" + FatherElement + "[" + @AttributeName + "='" + AttributeValue + "']");
XmlNodeList xx = xn.Item(0).ChildNodes;
for (int i = 0; i < ArrayLength & i < xx.Count; i++)
{
al.Add(xx.Item(i).InnerText);
}
return al;
}
#endregion