C#中读取xml文件指定节点

目录(?)[-]

1. XmlDocumentSelectSingleNode方法的使用
2. XmlDocumentSelectNodes方法的使用
3. 通过节点属性查找指定节点

 

参考：Select XML Nodes by Name

假设xml文件内容是

1. <?xml version="1.0" encoding="utf-8"?>
2. <Workflow>
3. <Activity>
4. <ActivityId>1</ActivityId>
5. <ActivityName>start</ActivityName>
6. <BindingPageId>1</BindingPageId>
7. <BindingRoleId>1</BindingRoleId>
8. <ActivityLevel>1</ActivityLevel>
9. </Activity>
10. <Activity>
11. <ActivityId>2</ActivityId>
12. <ActivityName>pass</ActivityName>
13. <BindingPageId>2</BindingPageId>
14. <BindingRoleId>2</BindingRoleId>
15. <ActivityLevel>2</ActivityLevel>
16. </Activity>
17. </Workflow>

<?xml version="1.0" encoding="utf-8"?>
<Workflow>
<Activity>
<ActivityId>1</ActivityId>
<ActivityName>start</ActivityName>
<BindingPageId>1</BindingPageId>
<BindingRoleId>1</BindingRoleId>
<ActivityLevel>1</ActivityLevel>
</Activity>
<Activity>
<ActivityId>2</ActivityId>
<ActivityName>pass</ActivityName>
<BindingPageId>2</BindingPageId>
<BindingRoleId>2</BindingRoleId>
<ActivityLevel>2</ActivityLevel>
</Activity>
</Workflow>

我们需要读取Activity节点下的内容，因为存在多个Activity，所以需要读取多个节点。可以使用 XmlDocument.SelectSingleNode和XmlDocument.SelectNodes方法查找节点。前一个是查找匹配的第一个节点，而后一个则会返回一个节点列表。

1.XmlDocument.SelectSingleNode方法的使用

首先创建一个读取xml文件的方法ReadXmlNode

1. /// <summary>
2. /// 读取xml中的指定节点的值
3. /// </summary>
4. public void ReadXmlNode(string filename)
5. {
6. XmlDocument xmlDoc = new XmlDocument();
7. try
8. {
9. xmlDoc.Load(filename);
10. //读取Activity节点下的数据。SelectSingleNode匹配第一个Activity节点
11. XmlNode root = xmlDoc.SelectSingleNode("//Activity");//当节点Workflow带有属性是，使用SelectSingleNode无法读取
12. if (root != null)
13. {
14. string ActivityId = (root.SelectSingleNode("ActivityId")).InnerText;
15. string ActivityName = (root.SelectSingleNode("ActivityName ")).InnerText;
16. string ActivityLevel = root.SelectSingleNode("ActivityLevel").InnerText;
17. Console.WriteLine("ActivityId:" + ActivityId + "/nActivityName:" + ActivityName + "/nActivityLevel:" + ActivityLevel);
18. }
19. else
20. {
21. Console.WriteLine("the node  is not existed");
22. //Console.Read();
23. }
24. }
25. catch (Exception e)
26. {
27. //显示错误信息
28. Console.WriteLine(e.Message);
29. }
30. }

/// <summary>
/// 读取xml中的指定节点的值
/// </summary>
public void ReadXmlNode(string filename)
{
XmlDocument xmlDoc = new XmlDocument();
try
{
xmlDoc.Load(filename);
//读取Activity节点下的数据。SelectSingleNode匹配第一个Activity节点
XmlNode root = xmlDoc.SelectSingleNode("//Activity");//当节点Workflow带有属性是，使用SelectSingleNode无法读取
if (root != null)
{
string ActivityId = (root.SelectSingleNode("ActivityId")).InnerText;
string ActivityName = (root.SelectSingleNode("ActivityName ")).InnerText;
string ActivityLevel = root.SelectSingleNode("ActivityLevel").InnerText;
Console.WriteLine("ActivityId:" + ActivityId + "/nActivityName:" + ActivityName + "/nActivityLevel:" + ActivityLevel);
}
else
{
Console.WriteLine("the node is not existed");
//Console.Read();
}
}
catch (Exception e)
{
//显示错误信息
Console.WriteLine(e.Message);
}
}

然后在主函数中调用该方法

1. class Program
2. {
3. static void Main(string[] args)
4. {
5. XMLOperation xmlOpr = new XMLOperation();
6. xmlOpr.ReadXmlNode("activity.xml");
7. Console.Read();
8. }
9. }

class Program
{
static void Main(string[] args)
{
XMLOperation xmlOpr = new XMLOperation();
xmlOpr.ReadXmlNode("activity.xml");
Console.Read();
}
}

输出结果为：

ActivityId:1 ActivityName:start ActivityLevel:1

2.XmlDocument.SelectNodes方法的使用

1. /// <summary>
2. /// 读取xml中的指定节点的值，如果有多个同名节点，则全部读取
3. /// </summary>
4. public void ReadXmlNodes(string filename)
5. {
6. XmlDocument xmlDoc = new XmlDocument();
7. try
8. {
9. xmlDoc.Load(filename);
10. XmlNodeList xnList = xmlDoc.SelectNodes("//Activity");
11. Console.WriteLine("共有{0}个节点", xnList.Count);//输出xnList中节点个数。
12. foreach (XmlNode xn in xnList)
13. {
14. //无法使用xn["ActivityId"].InnerText
15. string ActivityId = (xn.SelectSingleNode("ActivityId")).InnerText;
16. string ActivityName = xn.SelectSingleNode("ActivityName").InnerText;
17. string ActivityLevel = xn.SelectSingleNode("ActivityLevel").InnerText;
18. //  Console.WriteLine("ActivityId:" + ActivityId + "/nActivityName:" + ActivityName + "/nActivityLevel:" + ActivityLevel);
19. Console.WriteLine("ActivityId:  {0}/nActivityName:  {1}/nActivityLevel:  {2}", ActivityId, ActivityName, ActivityLevel);
20. }
21. }
22. catch (Exception e)
23. {
24. //显示错误信息
25. Console.WriteLine(e.Message);
26. }
27. }

/// <summary>
/// 读取xml中的指定节点的值，如果有多个同名节点，则全部读取
/// </summary>
public void ReadXmlNodes(string filename)
{
XmlDocument xmlDoc = new XmlDocument();
try
{
xmlDoc.Load(filename);
XmlNodeList xnList = xmlDoc.SelectNodes("//Activity");
Console.WriteLine("共有{0}个节点", xnList.Count);//输出xnList中节点个数。
foreach (XmlNode xn in xnList)
{
//无法使用xn["ActivityId"].InnerText
string ActivityId = (xn.SelectSingleNode("ActivityId")).InnerText;
string ActivityName = xn.SelectSingleNode("ActivityName").InnerText;
string ActivityLevel = xn.SelectSingleNode("ActivityLevel").InnerText;
// Console.WriteLine("ActivityId:" + ActivityId + "/nActivityName:" + ActivityName + "/nActivityLevel:" + ActivityLevel);
Console.WriteLine("ActivityId: {0}/nActivityName: {1}/nActivityLevel: {2}", ActivityId, ActivityName, ActivityLevel);
}
}
catch (Exception e)
{
//显示错误信息
Console.WriteLine(e.Message);
}
}

然后在主函数中调用该方法

1. class Program
2. {
3. static void Main(string[] args)
4. {
5. XMLOperation xmlOpr = new XMLOperation();
6. xmlOpr.ReadXmlNodes("activity.xml");
7. Console.Read();
8. }
9. }

class Program
{
static void Main(string[] args)
{
XMLOperation xmlOpr = new XMLOperation();
xmlOpr.ReadXmlNodes("activity.xml");
Console.Read();
}
}

输出结果为：

共有2个节点 ActivityId:  1 ActivityName:  start ActivityLevel:  1 ActivityId:  2 ActivityName:  pass ActivityLevel:  2

3.通过节点属性查找指定节点

参考http://www.csharp-examples.net/xml-nodes-by-attribute-value/，虽然没有用到参考文章中的方法，不过总觉得以后会用到的。

1. /// <summary>
2. ///通过ActivityLevel获取xmlnode，需要保证ActivityLevel在一个xml文档中是唯一的。
3. /// </summary>
4. public XmlNode getXmlNode(string filename, string activitylevel)
5. {
6. XmlDocument xmlDoc = new XmlDocument();
7. try
8. {
9. xmlDoc.Load(filename);
10. XmlNodeList xnList = xmlDoc.SelectNodes("//Activity");//当节点Workflow带有属性是，使用SelectSingleNode无法读取
11. foreach (XmlNode xn in xnList)
12. {
13. string ActivityLevel = xn.SelectSingleNode("ActivityLevel").InnerText;
14. if(activitylevel==ActivityLevel)
15. {
16. return xn;
17. }
18. }
19. }
20. catch (Exception e)
21. {
22. //显示错误信息
23. Console.WriteLine(e.Message);
24. }
25. return null;
26. }

/// <summary>
///通过ActivityLevel获取xmlnode，需要保证ActivityLevel在一个xml文档中是唯一的。
/// </summary>
public XmlNode getXmlNode(string filename, string activitylevel)
{
XmlDocument xmlDoc = new XmlDocument();
try
{
xmlDoc.Load(filename);
XmlNodeList xnList = xmlDoc.SelectNodes("//Activity");//当节点Workflow带有属性是，使用SelectSingleNode无法读取
foreach (XmlNode xn in xnList)
{
string ActivityLevel = xn.SelectSingleNode("ActivityLevel").InnerText;
if(activitylevel==ActivityLevel)
{
return xn;
}
}
}
catch (Exception e)
{
//显示错误信息
Console.WriteLine(e.Message);
}
return null;
}

然后在主函数中调用该方法

1. class Program
2. {
3. static void Main(string[] args)
4. {
5. XMLOperation xmlOpr = new XMLOperation();
6. XmlNode xn=xmlOpr.getXmlNode("activity.xml", "2");
7. string ActivityId = (xn.SelectSingleNode("ActivityId")).InnerText;
8. string ActivityName = (xn.SelectSingleNode("ActivityName ")).InnerText;
9. string ActivityLevel = xn.SelectSingleNode("ActivityLevel").InnerText;
10. Console.WriteLine("ActivityId:" + ActivityId + "/nActivityName:" + ActivityName + "/nActivityLevel:" + ActivityLevel);
11. Console.Read();
12. }
13. }

class Program
{
static void Main(string[] args)
{
XMLOperation xmlOpr = new XMLOperation();
XmlNode xn=xmlOpr.getXmlNode("activity.xml", "2");
string ActivityId = (xn.SelectSingleNode("ActivityId")).InnerText;
string ActivityName = (xn.SelectSingleNode("ActivityName ")).InnerText;
string ActivityLevel = xn.SelectSingleNode("ActivityLevel").InnerText;
Console.WriteLine("ActivityId:" + ActivityId + "/nActivityName:" + ActivityName + "/nActivityLevel:" + ActivityLevel);
Console.Read();
}
}

输出结果为：

ActivityId:2 ActivityName:pass ActivityLevel:2