C#Xpath解析HtmlDocument的使用方法与递归取得页面所有标签xpath值（附源码）

最新推荐文章于 2021-06-15 14:28:52 发布

转载最新推荐文章于 2021-06-15 14:28:52 发布 · 787 阅读

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原文链接：http://www.cnblogs.com/wangchuang/archive/2013/03/11/2953638.html

文章标签：

#c# #runtime #json

在学习HTML Xpath之前呢我们先来下载一下Dll文件
下载地址：http://htmlagilitypack.codeplex.com/
大家下载单击如下图片下载就行了
<ignore_js_op>

接下来就是在程序中引用一下，
<ignore_js_op>
然后就可以直接调用了，大家看看
代码吧

普通浏览复制代码

//htmlDcoument对象用来访问Html文档s
HtmlAgilityPack.HtmlDocument hd = new HtmlAgilityPack.HtmlDocument ( ) ;
//加载Html文档
hd.LoadHtml (strhtml ) ;
string str = hd.DocumentNode.SelectSingleNode ( "//*[@id='e_font']" ).OuterHtml ;

这样就可以得到一个标签的HTml代码了
OuterHtml是取包含本身的Html如果是InnerHtml就是取的包含在这个标签之内的所有Html代码了
这点大家要注意了
如果大家想获取Html代码的Xpath路径就是这部分

//*[@id='e_font']

复制代码

这个其实很简单只在大家安装一个Firbug就行了，
看下图片
<ignore_js_op>
大家只要进入选择模式，然后选择你要的内容，然后右键复制一下就行了。
然后放在SelectSingleNode（）方法里就OK了
下面我说说几个方法和属性的意思吧、
方法

SelectNodes 获取的是一个集合
SelectSingleNode 获取一个标签
SetAttributeValue 设置标签的属性值例如：SetAttributeValue("name","xpath-89");这说明把name属性的值修改为xpath-89
属性

OuterHtml 是取包含本身的Html
InnerHtml 取的包含在这个标签之内的所有Html代码了
XPath 获取相对应的Xpath值
Attributes 获取一个属性的值例如：Attributes("name")
也可以进行添加属性例如：

普通浏览复制代码

hd.DocumentNode.SelectSingleNode (item.Key ).Attributes.Add ( "xpathid", "xpath_1" ) ;

下面我写了一个递归获取Html页面所有Xpath值的方法大家看一下吧

普通浏览复制代码

//key（Xpath）,value（整个节点）
public List<ObjXpath> XpathList = new List<ObjXpath> ( ) ;
public string strhtml = "" ; //这里就是你的Html代码具体怎么获取请参考我的<a href=\"http://www.sufeinet.com/thread-3-1-1.html\" target=\"_blank\">HttpHelper</a>类吧
private int Index = 0 ;
//开始处理Node
private void SartNode ( )
{
//htmlDcoument对象用来访问Html文档s
HtmlAgilityPack.HtmlDocument hd = new HtmlAgilityPack.HtmlDocument ( ) ;
//加载Html文档
hd.LoadHtml (strhtml ) ;
HtmlNodeCollection htmllist = hd.DocumentNode.ChildNodes ;
Index = 0 ;
XpathList.Clear ( ) ;
foreach (HtmlNode em in htmllist )
{
Setxpath (em ) ;
}
}
/// <summary>
/// 递归获取Html Dom
/// </summary>
/// <param name="node">要处理的节点</param>
private void Setxpath (HtmlNode node )
{
foreach (HtmlNode item in node.ChildNodes )
{
if (item. XPath.Contains ( "#" ) )
{
continue ;
}
if (item.ChildNodes.Count > 0 )
{
XpathList.Add ( new ObjXpath ( ) { id = Index.ToString ( ), Key = item. XPath, Value = "" } ) ;
Index++ ;
Setxpath (item ) ;
}
else
{
XpathList.Add ( new ObjXpath ( ) { id = Index.ToString ( ), Key = item. XPath, Value = "" } ) ;
Index++ ;
}
}
}
public class ObjXpath
{
public string id { get ; set ; }
public string Key { get ; set ; }
public string Value { get ; set ; }
}

XpathList 就是获取的所有Xpath值了，大家有兴趣的话可以试试
我们先来看看效果吧
<ignore_js_op>
好了下面放出所有代码给大家

普通浏览复制代码

using System ;
using System. Collections. Generic ;
using System. ComponentModel ;
using System. Data ;
using System. Drawing ;
using System.Linq ;
using System. Text ;
using System.Windows.Forms ;
using System. Text. RegularExpressions ;
using System. Threading ;
using HtmlAgilityPack ;
using System. IO ;
using System. Runtime. Serialization.Json ;
namespace AutoXpathTools
{
public partial class Form1 : Form
{
public Form1 ( )
{
InitializeComponent ( ) ;
}
#region 私有变量和方法
//委托传入一个字符串
private delegate void SetListBox ( string str ) ;
//key（Xpath）,value（整个节点）
List<ObjXpath> XpathList = new List<ObjXpath> ( ) ;
private int Index = 0 ;
//htmlDcoument对象用来访问Html文档
HtmlAgilityPack.HtmlDocument hd = new HtmlAgilityPack.HtmlDocument ( ) ;
#endregion
//分析Xpath的所有代码
private void btnGetXpath_Click ( object sender, EventArgs e )
{
try
{
HttpHelper http = new HttpHelper ( ) ;
HttpItem item = new HttpItem ( ) { URL = textBox1. Text.Trim ( ), IsToLower = false, Encoding = "gbk" } ;
txtXml. Text = http.GetHtml (item ) ;
if (! string.IsNullOrWhiteSpace (txtXml. Text ) && txtXml. Text.Trim ( ).ToLower ( ) != "error" )
{
//加载Html文档
hd.LoadHtml (txtXml. Text ) ;
Thread pingTask = new Thread ( new ThreadStart ( delegate
{
//代码,线程要执行的代码
SartNode (txtXml. Text ) ;
} ) ) ;
pingTask.Start ( ) ;
}
else
{
txtXml. Text = "根据您的的ULR：" + textBox1. Text.Trim ( ) + "无法得到任何内容" ;
}
}
catch (Exception ex )
{
txtXml. Text = ex.Message.Trim ( ) ;
}
}
//开始处理Node
private void SartNode ( string strhtml )
{
//htmlDcoument对象用来访问Html文档s
HtmlAgilityPack.HtmlDocument hd = new HtmlAgilityPack.HtmlDocument ( ) ;
//加载Html文档
hd.LoadHtml (strhtml ) ;
HtmlNodeCollection htmllist = hd.DocumentNode.ChildNodes ;
Index = 0 ;
XpathList.Clear ( ) ;
foreach (HtmlNode em in htmllist )
{
Setxpath (em ) ;
}
}
/// <summary>
/// 递归获取Html Dom
/// </summary>
/// <param name="node">要处理的节点</param>
private void Setxpath (HtmlNode node )
{
foreach (HtmlNode item in node.ChildNodes )
{
if (item. XPath.Contains ( "#" ) )
{
continue ;
}
if (item.ChildNodes.Count > 0 )
{
XpathList.Add ( new ObjXpath ( ) { id = Index.ToString ( ), Key = item. XPath, Value = "" } ) ;
UIContorol (item. XPath ) ;
Index++ ;
Setxpath (item ) ;
}
else
{
XpathList.Add ( new ObjXpath ( ) { id = Index.ToString ( ), Key = item. XPath, Value = "" } ) ;
UIContorol (item. XPath ) ;
Index++ ;
}
}
}
//使用委托给控件赋值
private void UIContorol ( string str )
{
listBox1.Items.Add (str ) ;
toolStripStatusLabel1. Text = str ;
}
private void listBox1_SelectedValueChanged ( object sender, EventArgs e )
{
if (listBox1.SelectedItem != null )
{
txtPath. Text = listBox1.SelectedItem.ToString ( ).Trim ( ) ;
}
}
private void button3_Click ( object sender, EventArgs e )
{
txtContents. Text = hd.DocumentNode.SelectSingleNode (txtPath. Text.Trim ( ) ).OuterHtml ;
}
private void Form1_Load ( object sender, EventArgs e )
{
//HttpItem item = new HttpItem()
//{
// URL = "http://www.diandian.com/login",
// Method = "post",
// Cookie = "dtid=ZfXUVo1IsplHR4mHW1HYmgKbY4GJa003; kvf=1358855337188; alf=1; dru=1356356040; _l5=y",
// ContentType = "application/x-www-form-urlencoded",
// Postdata = "account=xinsuilie1998@163.com&password=wjlove520&nextUrl=&lcallback=&persistent=1",
// Referer = "http://www.diandian.com/logout?formKey=e4714d863c862a84fafd83d98e5ecb22"
//};
//HttpHelper http = new HttpHelper();
//string html = http.GetHtml(item);
//string cookie = item.Cookie;
//item = new HttpItem() { URL = "http://www.diandian.com/home", Cookie = cookie };
//html = http.GetHtml(item);
}
}
public class ObjXpath
{
public string id { get ; set ; }
public string Key { get ; set ; }
public string Value { get ; set ; }
}
}