一、XML的表示方式
|
Name |
Address |
City |
State |
Zip |
|
Crazy Zoo |
32 Turtle Lane |
Austin |
Tx |
12345 |
|
Chicago Zoo |
23 Zebra Ave |
Chicago |
IL |
(null) |
|
Hungry Zoo |
45 Lion st |
Miami |
FL |
33122 |
对于以上这样一个二维表，用XML的话有两种标识方式：
1.用“属性”来表示
每一列对应一个元素中的属性，表示空值时就是忽略掉这个属性就可以了
<?xml version="1.0" encoding="utf-8" ?>
<ZooRoot>
<ZooTable Name="Crazy Zoo" Address="32 Turtle Lane"
City="Austin" State="TX" Zip="12345" />
<ZooTable Name="Chicago Zoo" Address="23 Zebra Ave"
City="Chicago" State="IL" />
<ZooTable Name="Hungry Zoo" Address="45 Lion st"
City="Miami" State="FL" Zip="33122" />
</ZooRoot>
2.用“元素”来表示
<?xml version="1.0" encoding="utf-8" ?>
<ZooRoot>
<ZooTable>
<Name>Crazy Zoo</Name>
<Address>32 Turtle Lane</Address>
<City>Austin</City>
<State>TX</State>
<Zip>12345</Zip>
</ZooTable>
<ZooTable>
<Name>Chicago Zoo</Name>
<Address>23 Zebra Ave</Address>
<City>Chicago</City>
<State>IL</State>
</ZooTable>
<ZooTable>
<Name>Hungry Zoo</Name>
<Address>45 Lion st</Address>
<City>Miami</City>
<State>FL</State>
<Zip>33122</Zip>
</ZooTable>
</ZooRoot>
二、使用xmlhelper
1. 创建一个xml文档，并在文档中创建根节点
XmlDocument doc = XmlHelper.CreateXmlDocument();
XmlNode newNode = doc.CreateElement("ZooRoot");
XmlNode rootNode = doc.AppendChild(newNode);
2. 接下来创建整个用属性表示的文档
///
/// First Row
///
newNode = doc.CreateElement("ZooTable");
XmlHelper.CreateAttribute(newNode, "Name", "Crazy Zoo");
XmlHelper.CreateAttribute(newNode, "Address", "32 Turtle Lane");
XmlHelper.CreateAttribute(newNode, "City", "Austin");
XmlHelper.CreateAttribute(newNode, "State", "TX");
XmlHelper.CreateAttribute(newNode, "Zip", "12345");
rootNode.AppendChild(newNode);
///
/// Second Row
///
newNode = doc.CreateElement("ZooTable");
XmlHelper.CreateAttribute(newNode, "Name", "Chicago Zoo");
XmlHelper.CreateAttribute(newNode, "Address", "23 Zebra Ave");
XmlHelper.CreateAttribute(newNode, "City", "Chicago");
XmlHelper.CreateAttribute(newNode, "State", "IL");
rootNode.AppendChild(newNode);
///
/// Third Row
///
newNode = doc.CreateElement("ZooTable");
XmlHelper.CreateAttribute(newNode, "Name", "Hungry Zoo");
XmlHelper.CreateAttribute(newNode, "Address", "45 Lion st");
XmlHelper.CreateAttribute(newNode, "City", "Miami");
XmlHelper.CreateAttribute(newNode, "State", "FL");
XmlHelper.CreateAttribute(newNode, "Zip", "33122");
rootNode.AppendChild(newNode);
3. Xpath 的查询
3.1 查找单个元素
string xpathQuery = "/ZooRoot/ZooTable[@Name='Chicago Zoo']";
XmlNode selectedNode = doc.SelectSingleNode(xpathQuery);
基于属性的查找
string xpathQuery = "/ZooRoot/ZooTable/Name='Chicago Zoo'";
XmlNode selectedNode = doc.SelectSingleNode(xpathQuery);
基于元素值的查找
string xpathQuery =
"/ZooRoot/ZooTable/Name='Chicago Zoo' and @City=’Chicago’";
XmlNode selectedNode = doc.SelectSingleNode(xpathQuery);
可以是有多个条件
3.2 返回多条记录
string xpathQuery =
"/ZooRoot/ZooTable/[@Name='Chicago Zoo']/Classification";
XmlNodeList nodeList = doc.SelectNodes(xpathQuery);
string xpathQuery =
"/ZooRoot/ZooTable/[@Name='Chicago Zoo']/child::*";
XmlNodeList nodeList = doc.SelectNodes(xpathQuery);
4 在已存的XML文件节点中插入新节点
string xpathQuery = "/ZooRoot/ZooTable";
XmlNodeList nodeList = doc.SelectNodes(xpathQuery);
然后使用foreach遍历
int index = 0;
foreach (XmlNode nodeFromList in nodeList)
{
///
/// each 'nodeFromList' is going to
/// be the parent node to which
/// we need to add the 'Classification' child nodes
///
foreach (string classificationName in classificationData[index])
{
newNode = doc.CreateElement("Classification");
XmlHelper.CreateAttribute(newNode, "Type",
classificationName);
nodeFromList.AppendChild(newNode);
}
index++;
}
5. 在现存的节点中修改属性值
XmlNodeList nodeList = doc.SelectNodes(
"/ZooRoot/ZooTable/Classification[@Type='Primates']");
foreach (XmlNode node in nodeList)
{
XmlHelper.SetAttributeValue(node, "Type", "Monkeys");
}
6. 复制一个同类型节点，并修改为新的值
///
/// Get Access to the node that we need to copy
///
XmlNode nodeToCopy = doc.SelectSingleNode(
"/ZooRoot/ZooTable[@Name='Chicago Zoo']");
///
/// Copy the node
///
//true means that child nodes will be copied as well
XmlNode newNode = doc.ImportNode(nodeToCopy, true);
///
/// Change the attributes that are different
///
XmlHelper.SetAttributeValue(newNode, "Name", "New York Zoo");
XmlHelper.SetAttributeValue(newNode, "Address",
"235 Congestion Ave");
XmlHelper.SetAttributeValue(newNode, "City", "New York");
XmlHelper.SetAttributeValue(newNode, "State", "NY");
XmlHelper.SetAttributeValue(newNode, "Zip", "44444");
///
/// Add child node. Note that the new node
/// shares the same parent as the node
/// we are copying from, so we might as well
/// access the parent node from the node
/// that we are copying from.
///
nodeToCopy.ParentNode.AppendChild(newNode);
7. 复制属性值
///
/// Create a new node and set its attributes
///
XmlNode newNode = doc.CreateElement("ZooTable");
XmlHelper.CreateAttribute(newNode, "Name", "New York Zoo");
XmlHelper.CreateAttribute(newNode, "Address",
"235 Congestion Ave");
XmlHelper.CreateAttribute(newNode, "City", "New York");
XmlHelper.CreateAttribute(newNode, "State", "NY");
XmlHelper.CreateAttribute(newNode, "Zip", "44444");
/// Get Access to the node that we need to copy
///
XmlNode nodeToCopy = doc.SelectSingleNode(
"/ZooRoot/ZooTable[@Name='Chicago Zoo']");
///
/// Copy all the attributes of the child nodes
///
foreach (XmlNode childNode in nodeToCopy.ChildNodes)
{
XmlNode newChildNode = doc.CreateElement("Classification");
XmlHelper.CreateAttribute(newChildNode, "Type", "");
XmlHelper.CopyAttribute(childNode, newChildNode, "Type");
newNode.AppendChild(newChildNode);
}
///
/// Add child node. Note that the new node
/// shares the same parent as the node
/// we are copying from, so we might as well
/// access the parent node from the node
/// that we are copying from.
///
nodeToCopy.ParentNode.AppendChild(newNode);
8. 作为datatable的数据源
8.1 将xmlNodeList转换为Datatable
XmlHelper.GetDataTable( XmlNodeList nodelist )
8.2 将xmlNodeList转换为Datatable,并设置一列为主键
XmlHelper.GetDataTable( XmlNodeList nodelist,
string primaryKeyColumn, bool autoIncrement)
8.3 将xml从datatable到nodelist的更新
XmlHelper.UpdateChildNodesWithDataTable(XmlNode parentNode,
DataTable table, string keyField)
8.4 将datarow中的数据作为属性复制到一个xmlnode中
XmlHelper.CopyAttributes(DataRow fromRow, XmlNode toNode)
8.5 返回一个属性数组，对应二维表中的一列
XmlHelper.GetAttributeArray(XmlNodeList nodeList, string attributeName)
XmlNodeList nodeList = doc.SelectNodes("/ZooRoot/ZooTable");
this.lstZoos.DataSource =
XmlHelper.GetAttributeArray(nodeList, "Name");
以上是将某一列作为某个listbox控件的数据源的示例
XmlNodeList nodeList = doc.SelectNodes("/ZooRoot/ZooTable");
this.grdZoos.DataSource = XmlHelper.GetDataTable(nodeList);
以上对将多条数据（nodelist）作为datagrid控件的数据源
从datatable更新xml的示例
///
/// Get access to the DataTable that was modified in DataGrid
///
DataTable table = (DataTable)this.grdZoos.DataSource;
///
/// Get access to the parent node whose child are
/// part of the datatable
///
XmlNode parentNode = doc.SelectSingleNode("/ZooRoot");
///
/// Update the XmlDocument with changes made on DataGrid
///
XmlHelper.UpdateChildNodesWithDataTable(parentNode,
table, "Name");
8.6 从一个xml节点导入到另一个xml节点
///
/// Create a master XmlDocument that will organize data by Country
///
XmlDocument docMaster = XmlHelper.CreateXmlDocument();
XmlNode newNode = docMaster.CreateElement("root");
XmlNode rootNode = docMaster.AppendChild(newNode);
newNode = docMaster.CreateElement("Country");
XmlHelper.CreateAttribute(newNode, "Name", "USA");
XmlNode usaRoot = rootNode.AppendChild(newNode);
///
/// Select the nodes to be imported
///
XmlNodeList nodeList = doc.SelectNodes("/ZooRoot/ZooTable");
///
/// Import nodes
///
foreach (XmlNode sourceNode in nodeList)
{
newNode = docMaster.ImportNode(sourceNode, true);
usaRoot.AppendChild(newNode);
}
this.txtQueryResults.Text = XmlHelper.DocumentToString(docMaster);
9. xmlhelper的调试
XmlHelper.DocumentToString 和 XmlHelper.NodeToString 这两个方法通常用来调试。
Trace.WriteLine(XmlHelper.NodeToString(currentNode))
10. Insert方法
XmlHelper.Insert(XmlDocument doc, string xpath)
XmlHelper.Insert(XmlDocument doc, string xpath,
string[] fields, string[] values)
XmlHelper.Insert(XmlDocument doc, string xpath,
NameValueCollection nameValuePairs)
System.Collections.Specialized.NameValueCollection
XmlHelper.Insert(XmlDocument doc, string xpath, DataRow rowValues)
XmlHelper.Insert(XmlDocument doc,
string xpath, DataTable table) ////// Create the XmlDocument and specify name of the root node///
doc = XmlHelper.CreateXmlDocument("ZooRoot");////// First Row///
string[] fields = new string[]
{"Name", "Address", "City", "State", "Zip"};
string[] values = new string[]
{"Crazy Zoo", "32 Turtle Lane", "Austin", "TX", "12345"};
XmlHelper.Insert(doc, "ZooTable", fields, values);////// Second Row (Zip is missing)///
string[] fields2 = new string[]
{"Name", "Address", "City", "State"};
values = new string[]
{"Chicago Zoo", "23 Zebra Ave", "Chicago", "IL"};
XmlHelper.Insert(doc, "ZooTable", fields2, values);////// Third Row///
values = new string[]
{"Hungry Zoo", "45 Lion st", "Miami", "FL", "33122"};
XmlHelper.Insert(doc, "ZooTable", fields, values);
////// Insert Classification Data///
values = new string[]{"Reptiles", "Birds", "Primates"};
XmlHelper.Insert(doc,
"ZooTable[@Name='Crazy Zoo']/Classification", "Type", values);
values
= new string[] {"Fish", "Mammals", "Primates"};values
= new string[] {"Arachnids", "Rodents"};11. Update方法
XmlHelper.Update(doc,
"ZooTable/Classification[@Type='Primates']", "Type", "Monkeys");
12. Delete方法
XmlHelper.Delete(XmlDocument doc, string xpath)
XmlHelper.Delete(XmlDocument doc, string xpath, string field)
13. Query方法，返回一个datatable
XmlHelper.Query(XmlDocument doc, string xpath)
XmlHelper.QueryScalar(XmlDocument doc, string xpath, string field)
XmlHelper.QueryField(XmlDocument doc, string xpath, string field)
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