大家想必一定都了解XML，利用XML技术来存储数据和文档是一件很容易的事情，.NET Framework 在它的命名空间System.Xml 就提供了一种可以很方便的操作xml的类XmlDocument，它使用起来非常容易，XmlDocument 其实就是一个简单的树。下面详细的介绍XmlDocument 的使用方法。
下面是这个类中操作节点的常用方法。
// create a new node in the document object from the source node
//and name it as "sName"
// the return value indicates success or failure
public bool AddNode(XmlNode oSource, String sName);
// same as above except that it also specifies the parent node of the
// newly created node
// the return value indicates success or failure (returns false if the
// parent node does not exist)
public bool AddNode(XmlNode oSource, String sName, String sParent);
// create a set of new nodes in the document object from the source node
// list and name them as "sName"
// the return value indicates success or failure
public bool AddNodes(XmlNodeList oSourceList, String sName);
// same as above except that it also specifies the parent node of the
// newly created nodes the return value indicates success or failure
// (returns false if the parent node
// does not exist)
public bool AddNodes(XmlNodeList oSourceList, String sName, String sParent);
// merge the source node into a node named "sName" in the document object
// the node named "sName" will be created if it does not exist
// the return value indicates success or failure
public bool MergeNode(XmlNode oSource, String sName);
// same as above except that it also specifies the parent node of the merged node
// the return value indicates success or failure (returns false if the parent node
// does not exist)
public bool MergeNode(XmlNode oSource, String sName, String sParent);
下面我们给一个增加节点的例子
docVechile.xml
<VehicleData>
<Record>
<id>1001</id>
<make>Ford</make>
<model>Escort</model>
<year>1984</year>
</Record>
<Record>
<id>1002</id>
<make>Toyota</make>
<model>Tercel</model>
<year>1996</year>
</Record>
<Record>
<id>1003</id>
<make>Mazda</make>
<model>GLC</model>
<year>1985</year>
</Record>
</VehicleData>
docDriver.xml
<DriverData>
<Record>
<id>1</id>
<firstname>Albert</firstname>
<lastname>Einstein</lastname>
</Record>
<Record>
<id>2</id>
<firstname>Clint</firstname>
<lastname>Eastwood</lastname>
</Record>
<Record>
<id>3</id>
<firstname>James</firstname>
<lastname>Bond</lastname>
</Record>
</DriverData>
下面的代码将增加一个节点：
Dim myDoc As XMLDocumentEx = New XMLDocumentEx()
myDoc.LoadXml("<Data></Data>")
myDoc.AddNode(docVehicle.SelectSingleNode("//Record"), "VehicleRecord", "Data")
myDoc.AddNode(docDriver.SelectSingleNode("//Record"), "DriverRecord", "Data")
myDoc.xml<Data>
<VehicleRecord>
<id>...</id>
<make>...</make>
<model>...</model>
<year>...</year>
</ Vehicle Record>
<DriverRecord>
<id>...</id>
<firstname>...</firstname>
<lastname>...</lastname>
</DriverRecord>
</Data> 我们也可是使用AddNodes方法把一个记录集的所有记录增加到节点上：Dim myDoc As XMLDocumentEx = New XMLDocumentEx()
myDoc.LoadXml("<Data> <VehicleData></Vehicle Data><DriverData></DriverData> </Data>")
myDoc.AddNodes(docVehicle.SelectNodes("//Record"), "VehicleRecord", " Vehicle Data")
myDoc.AddNodes(docDriver.SelectNodes("//Record"), "DriverRecord", "DriverData")结果如下：myDoc.xml<Data>
<VehicleData>
<VehicleRecord>
<id>1001</id>
<make>Ford</make>
<model>Escort</model>
<year>1984</year>
</VehicleRecord>
<VehicleRecord>
<id>1002</id>
<make>Toyota</make>
<model>Tercel</model>
<year>1996</year>
</VehicleRecord>
<VehicleRecord>
<id>1003</id>
<make>Mazda</make>
<model>GLC</model>
<year>1985</year>
</VehicleRecord>
</VehicleData>
<DriverData>
<DriverRecord>
<id>1</id>
<firstname>Albert</firstname>
<lastname>Einstein</lastname>
</DriverRecord>
<DriverRecord>
<id>2</id>
<firstname>Clint</firstname>
<lastname>Eastwood</lastname>
</DriverRecord>
<DriverRecord>
<id>3</id>
<firstname>James</firstname>
<lastname>Bond</lastname>
</DriverRecord>
</DriverData>
</Data>下面我介绍如何合并节点。假设我们有两个XmlDocument文件docBook1和docBook2，这两个文档都包含 <Book> 节点. 在docBook1 中的这个 <Book> 节点 包含 <Introduction>, <Chapter1>, and <Chapter2>. 在docBook2中的这个 <Book> 节点 包含 <Chapter3>, <Chapter4>, and <Chapter5>. 下面的代码演示如何合并这两个book节点:Dim myDoc As XMLDocumentEx = New XMLDocumentEx()
myDoc.LoadXml("<Data> <Book></Book></Data> ")
myDoc.MergeNode(docBook1.SelectSingleNode("//Book"), "Book", "Data ")
myDoc.MergeNode(docBook2.SelectSingleNode("//Book"), "Book", "Data")合并后的效果如下：myDoc.xml<Data>
<Book>
<Introduction>...</Introduction>
< Chapter1 >...</Chapter1>
<Chapter2>...</Chapter2>
<Chapter3>...</Chapter3>
<Chapter4>...</Chapter4>
<Chapter5>...</Chapter5>
</Book>
</Data>下面是所有的源代码：sealed public class XMLDocumentEx: XmlDocument
{
public bool AddNode(XmlNode oSource, String sName)
{
return AddNode(oSource, sName, null);
}
public bool AddNode(XmlNode oSource, String sName, String sParent)
{
try
{
if(sName!=null&&oSource!= null)
{
// create the new node with given name
XmlNode oNewNode = CreateElement(sName);
// copy the contents from the source node
oNewNode.InnerXml = oSource.InnerXml;
// if there is no parent node specified, then add
// the new node as a child node of the root node
if(sParent!= null) sParent = sParent.Trim();
if(sParent== null||sParent.Equals(String.Empty))
{
DocumentElement.AppendChild(oNewNode);
return true;
}
// otherwise add the new node as a child of the parent node
else
{
if (!sParent.Substring(0,2).Equals("//")) sParent = "//"+sParent;
XmlNode oParent = SelectSingleNode(sParent);
if (oParent!=null)
{
oParent.AppendChild(oNewNode);
return true ;
}
}
}
}
catch (Exception)
{
// error handling code
}
return false;
}
public bool AddNodes(XmlNodeList oSourceList, String sName)
{
return AddNodes(oSourceList, sName, null);
}
public bool AddNodes(XmlNodeList oSourceList, String sName, String sParent)
{
try
{
if(oSourceList!= null)
{
// call AddNode for each item in the source node list
// return true only if all nodes are added successfully
int i = 0;
while(i<oSourceList.Count)
{
if (!AddNode(oSourceList.Item(i),sName,sParent)) return false;
i++;
}
return true;
}
}
catch (Exception)
{
// error handling code
}
return false;
}
public bool MergeNode(XmlNode oSource, String sName)
{
return MergeNode(oSource, sName, null );
}
public bool MergeNode(XmlNode oSource, String sName, String sParent)
{
try
{
if(sName!=null&&oSource!= null)
{
XmlNode theNode = null ;
// if there is no parent node specified ...
if(sParent!= null) sParent = sParent.Trim();
if(sParent== null||sParent.Equals(String.Empty))
{
// if the node with specified name does not exist,
// add it as a child node of the root node
theNode = SelectSingleNode("//"+sName);
if (theNode==null)
{
theNode = CreateElement(sName);
DocumentElement.AppendChild(theNode);
}
}
// if the parent node is specified ...
else
{
// find the parent node
if (!sParent.Substring(0,2).Equals("//")) sParent = "//"+sParent;
XmlNode theParent = SelectSingleNode(sParent);
if (theParent!=null)
{
// if the node with specified name does not exist, create
// it first, then add it as a child node of the parent node
theNode = theParent.SelectSingleNode(sName);
if(theNode==null)
{
theNode = CreateElement(sName);
theParent.AppendChild(theNode);
}
}
}
// merge the content of the source node into
// the node with specified name
if(theNode!= null)
{
theNode.InnerXml += oSource.InnerXml;
return true;
}
}
}
catch (Exception)
{
}
return false;
}
}