课题_C#Xpath解析HtmlDocument的使用方法与递归取得页面所有标签xpath值

C#Xpath解析HtmlDocument的使用方法与递归取得页面所有标签xpath值在学习HTML Xpath之前呢我们先来下载一下Dll文件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1. //htmlDcoument对象用来访问Html文档s2. HtmlAgilityPack.HtmlDocument hd = new HtmlAgilityPack.HtmlDocument();3. //加载Html文档4. hd.LoadHtml(strhtml);5. 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1.//*[@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HtmlInnerHtml 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1.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1. //key（Xpath）,value（整个节点）2. public List<ObjXpath> XpathList = new List<ObjXpath>();3. 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=\"/thread-3-1-1.html\" target=\"_blank\">HttpHelper</a>类吧4. private int Index = 0;5.//开始处理Node6. private void SartNode()7. {8. //htmlDcoument对象用来访问Html文档s9. HtmlAgilityPack.HtmlDocument hd = new HtmlAgilityPack.HtmlDocument();10. //加载Html文档11. hd.LoadHtml(strhtml);12. HtmlNodeCollection htmllist = hd.DocumentNode.ChildNodes;13. Index = 0;14. XpathList.Clear();15. foreach (HtmlNode em in htmllist)16. {17. Setxpath(em);18. }19. }20. /// <summary>21. /// 递归获取Html Dom22. /// </summary>23. /// <param name="node">要处理的节点</param>24. private void Setxpath(HtmlNode node)25. {26. foreach (HtmlNode item in node.ChildNodes)27. {28. if (item.XPath.Contains("#"))29. {30. continue;31. }32. if (item.ChildNodes.Count > 0)33. {34. XpathList.Add(new ObjXpath() { id = Index.ToString(),Key = item.XPath, Value = "" });35. Index++;36. Setxpath(item);37. }38. else39. {40. XpathList.Add(new ObjXpath() { id = Index.ToString(),Key = item.XPath, Value = "" });41. Index++;42. }43. }44. }45. public class ObjXpath46. {47. public string id { get; set; }48. public string Key { get; set; }49. public string Value { get; set; }50. }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ing System;ing System.Collections.Generic;ing ponentModel;ing System.Data;ing System.Drawing;ing System.Linq;ing System.Text;ing System.Windows.Forms;ing System.Text.RegularExpressions;ing System.Threading;ing HtmlAgilityPack;ing System.IO;ing System.Runtime.Serialization.Json;14.space AutoXpathTools16.{17. public partial class Form1 : Form18. {19. public Form1()20. {21. InitializeComponent();22. }23.24. #region 私有变量和方法25.26. //委托传入一个字符串27. private delegate void SetListBox(string str);28.29. //key（Xpath）,value（整个节点）30. List<ObjXpath> XpathList = new List<ObjXpath>();31. private int Index = 0;32. //htmlDcoument对象用来访问Html文档33. HtmlAgilityPack.HtmlDocument hd = new HtmlAgilityPack.HtmlDocument();34.35. #endregion36.37. //分析Xpath的所有代码38. private void btnGetXpath_Click(object sender, EventArgs e)39. {40. try41. {42. HttpHelper http = new HttpHelper();43. HttpItem item = new HttpItem() { URL = textBox1.Text.Trim(), IsToLower = false, Encoding = "gbk" };44. txtXml.Text = http.GetHtml(item);45. if (!string.IsNullOrWhiteSpace(txtXml.Text) && txtXml.Text.Trim().ToLower() != "error")46. {47. //加载Html文档48. hd.LoadHtml(txtXml.Text);49.50.51. Thread pingTask = new Thread(new ThreadStart(delegate52. {53. //代码,线程要执行的代码54. SartNode(txtXml.Text);55. }));56. pingTask.Start();57.58. }59. else60. {61. txtXml.Text = "根据您的的ULR：" + textBox1.Text.Trim() + "无法得到任何内容";62. }63. }64. catch (Exception ex)65. {66. txtXml.Text = ex.Message.Trim();67. }68. }69.70.71. //开始处理Node72. private void SartNode(string strhtml)73. {74. //htmlDcoument对象用来访问Html文档s75. HtmlAgilityPack.HtmlDocument hd = new HtmlAgilityPack.HtmlDocument();76. //加载Html文档77. hd.LoadHtml(strhtml);78. HtmlNodeCollection htmllist = hd.DocumentNode.ChildNodes;79. Index = 0;80. XpathList.Clear();81. foreach (HtmlNode em in htmllist)82. {83. Setxpath(em);84. }85. }86. /// <summary>87. /// 递归获取Html Dom88. /// </summary>89. /// <param name="node">要处理的节点</param>90. private void Setxpath(HtmlNode node)91. {92. foreach (HtmlNode item in node.ChildNodes)93. {94. if (item.XPath.Contains("#"))95. {96. continue;97. }98. if (item.ChildNodes.Count > 0)99. {100. XpathList.Add(new ObjXpath() { id = Index.ToString() , Key = item.XPath, Value = "" });101. UIContorol(item.XPath);102. Index++;103. Setxpath(item);104. }105. else106. {107. XpathList.Add(new ObjXpath() { id = Index.ToString() , Key = item.XPath, Value = "" });108. UIContorol(item.XPath);109. Index++;110. }111. }112. }113.114. //使用委托给控件赋值115. private void UIContorol(string str)116. {117. listBox1.Items.Add(str);118. toolStripStatusLabel1.Text = str;119. }120.121. private void listBox1_SelectedValueChanged(object sender, Ev entArgs e)122. {123. if (listBox1.SelectedItem != null)124. {125. txtPath.Text = listBox1.SelectedItem.ToString().Trim();126. }127. }128.129. private void button3_Click(object sender, EventArgs e)130. {131. txtContents.Text = hd.DocumentNode.SelectSingleNode(txt Path.Text.Trim()).OuterHtml;132. }133.134. private void Form1_Load(object sender, EventArgs e)135. {136. //HttpItem item = new HttpItem()137. //{138. // URL = "/login",139. // Method = "post",140. // Cookie = "dtid=ZfXUVo1IsplHR4mHW1HYmgKbY4GJa00 3; kvf=1358855337188; alf=1; dru=1356356040; _l5=y",141. // ContentType = "application/x-www-form-urlencoded",142. // Postdata = "account=xinsuilie1998@&passwor d=wjlove520&nextUrl=&lcallback=&persistent=1",143. // Referer = "/logout?formKey= e4714d863c862a84fafd83d98e5ecb22"144. //};145. //HttpHelper http = new HttpHelper();146. //string html = http.GetHtml(item);147. //string cookie = item.Cookie;148. //item = new HttpItem() { URL = "http://www.diandian.co m/home", Cookie = cookie };149. //html = http.GetHtml(item);150. }151. }152. public class ObjXpath153. {154. public string id { get; set; }155. public string Key { get; set; }156. public string Value { get; set; } 157. }158.}就到这里吧。