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
1<vehicledata>
2<record>
3<id>1001</id>
4<make>Ford</make>
5<model>Escort</model>
6<year>1984</year>
7</record>
8<record>
9<id>1002</id>
10<make>Toyota</make>
11<model>Tercel</model>
12<year>1996</year>
13</record>
14<record>
15<id>1003</id>
16<make>Mazda</make>
17<model>GLC</model>
18<year>1985</year>
19</record>
20</vehicledata>
docDriver.xml
1<driverdata>
2<record>
3<id>1</id>
4<firstname>Albert</firstname>
5<lastname>Einstein</lastname>
6</record>
7<record>
8<id>2</id>
9<firstname>Clint</firstname>
10<lastname>Eastwood</lastname>
11</record>
12<record>
13<id>3</id>
14<firstname>James</firstname>
15<lastname>Bond</lastname>
16</record>
17</driverdata>
下面的代码将增加一个节点：
Dim myDoc As XMLDocumentEx = New XMLDocumentEx()
myDoc.LoadXml("
1<data></data>
") myDoc.AddNode(docVehicle.SelectSingleNode("//Record"), "VehicleRecord", "Data") myDoc.AddNode(docDriver.SelectSingleNode("//Record"), "DriverRecord", "Data")
_myDoc.xml_
1<data>
2<vehiclerecord>
3<id>...</id>
4<make>...</make>
5<model>...</model>
6<year>...</year>
7<!-- Vehicle Record-->
8<driverrecord>
9<id>...</id>
10<firstname>...</firstname>
11<lastname>...</lastname>
12</driverrecord>
13</vehiclerecord></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("
1<data> <vehicledata><driverdata></driverdata> </vehicledata></data>
") myDoc.AddNodes(docVehicle.SelectNodes("//Record"), "VehicleRecord", " Vehicle Data") myDoc.AddNodes(docDriver.SelectNodes("//Record"), "DriverRecord", "DriverData")
结果如下：
_myDoc.xml_
1<data>
2<vehicledata>
3<vehiclerecord>
4<id>1001</id>
5<make>Ford</make>
6<model>Escort</model>
7<year>1984</year>
8</vehiclerecord>
9<vehiclerecord>
10<id>1002</id>
11<make>Toyota</make>
12<model>Tercel</model>
13<year>1996</year>
14</vehiclerecord>
15<vehiclerecord>
16<id>1003</id>
17<make>Mazda</make>
18<model>GLC</model>
19<year>1985</year>
20</vehiclerecord>
21</vehicledata>
22<driverdata>
23<driverrecord>
24<id>1</id>
25<firstname>Albert</firstname>
26<lastname>Einstein</lastname>
27</driverrecord>
28<driverrecord>
29<id>2</id>
30<firstname>Clint</firstname>
31<lastname>Eastwood</lastname>
32</driverrecord>
33<driverrecord>
34<id>3</id>
35<firstname>James</firstname>
36<lastname>Bond</lastname>
37</driverrecord>
38</driverdata>
39</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
1<book> 节点. 在docBook1 中的这个 <book> 节点 包含
2
3
4 <introduction>, <chapter1>, and <chapter2>.
5
6
7 在docBook2中的这个 <book> 节点 包含 <chapter3>, <chapter4>, and <chapter5>.
8
9
10 下面的代码演示如何合并这两个book节点:
11
12
13 Dim myDoc As XMLDocumentEx = New XMLDocumentEx()
14 myDoc.LoadXml("<data> <book></book></data> ")
15 myDoc.MergeNode(docBook1.SelectSingleNode("//Book"), "Book", "Data ")
16 myDoc.MergeNode(docBook2.SelectSingleNode("//Book"), "Book", "Data")
17
18
19 合并后的效果如下：
20
21
22 _myDoc.xml_
23
24
25 <data>
26<book>
27<introduction>...</introduction>
28 < Chapter1 >...</book></data></chapter5></chapter4></chapter3></book></chapter2></chapter1>
29<chapter2>...</chapter2>
30<chapter3>...</chapter3>
31<chapter4>...</chapter4>
32<chapter5>...</chapter5>
33</introduction></book>
34
35
36
37 下面是所有的源代码：
38
39
40 sealed public class XMLDocumentEx: XmlDocument
41 {
42 public bool AddNode(XmlNode oSource, String sName)
43 {
44 return AddNode(oSource, sName, null);
45 }
46 public bool AddNode(XmlNode oSource, String sName, String sParent)
47 {
48 try
49 {
50 if(sName!=null&&oSource!= null)
51 {
52 // create the new node with given name
53 XmlNode oNewNode = CreateElement(sName);
54 // copy the contents from the source node
55 oNewNode.InnerXml = oSource.InnerXml;
56 // if there is no parent node specified, then add
57 // the new node as a child node of the root node
58 if(sParent!= null) sParent = sParent.Trim();
59 if(sParent== null||sParent.Equals(String.Empty))
60 {
61 DocumentElement.AppendChild(oNewNode);
62 return true;
63 }
64 // otherwise add the new node as a child of the parent node
65 else
66 {
67 if (!sParent.Substring(0,2).Equals("//")) sParent = "//"+sParent;
68 XmlNode oParent = SelectSingleNode(sParent);
69 if (oParent!=null)
70 {
71 oParent.AppendChild(oNewNode);
72 return true ;
73 }
74 }
75 }
76 }
77 catch (Exception)
78 {
79 // error handling code
80 }
81 return false;
82 }
83 public bool AddNodes(XmlNodeList oSourceList, String sName)
84 {
85 return AddNodes(oSourceList, sName, null);
86 }
87 public bool AddNodes(XmlNodeList oSourceList, String sName, String sParent)
88 {
89 try
90 {
91 if(oSourceList!= null)
92 {
93 // call AddNode for each item in the source node list
94 // return true only if all nodes are added successfully
95 int i = 0;
96 while(i<oSourceList.Count)
97 {
98 if (!AddNode(oSourceList.Item(i),sName,sParent)) return false;
99 i++;
100 }
101 return true;
102 }
103 }
104 catch (Exception)
105 {
106 // error handling code
107 }
108 return false;
109 }
110 public bool MergeNode(XmlNode oSource, String sName)
111 {
112 return MergeNode(oSource, sName, null );
113 }
114 public bool MergeNode(XmlNode oSource, String sName, String sParent)
115 {
116 try
117 {
118 if(sName!=null&&oSource!= null)
119 {
120 XmlNode theNode = null ;
121 // if there is no parent node specified ...
122 if(sParent!= null) sParent = sParent.Trim();
123 if(sParent== null||sParent.Equals(String.Empty))
124 {
125 // if the node with specified name does not exist,
126 // add it as a child node of the root node
127 theNode = SelectSingleNode("//"+sName);
128 if (theNode==null)
129 {
130 theNode = CreateElement(sName);
131 DocumentElement.AppendChild(theNode);
132 }
133 }
134 // if the parent node is specified ...
135 else
136 {
137 // find the parent node
138 if (!sParent.Substring(0,2).Equals("//")) sParent = "//"+sParent;
139 XmlNode theParent = SelectSingleNode(sParent);
140 if (theParent!=null)
141 {
142 // if the node with specified name does not exist, create
143 // it first, then add it as a child node of the parent node
144 theNode = theParent.SelectSingleNode(sName);
145 if(theNode==null)
146 {
147 theNode = CreateElement(sName);
148 theParent.AppendChild(theNode);
149 }
150 }
151 }
152 // merge the content of the source node into
153 // the node with specified name
154 if(theNode!= null)
155 {
156 theNode.InnerXml += oSource.InnerXml;
157 return true;
158 }
159 }
160 }
161 catch (Exception)
162 {
163 }
164 return false;
165 }
166 }</book>