Asp.net parses HTML and uses XPath to analyze and extract content

There are many types of HTML Parser, the most commonly used is htmlagilitypack and sgmlreader (http://sourceforge.net/projects/dekiwiki/files/SgmlReader ).

Here we useHtmlagilitypack:

: Http://htmlagilitypack.codeplex.com

At the same time, the official website provides a tool to automatically generate the XPath path, namely, the URL of the tool.

For more information about XPath expressions and relevant tutorials, see:Selection of XPath expressions [updating...]

There are many ways to obtain HTML:

1. Simulate logon and obtain page information through the httpwebrequest class

2. Simulate logon with a third-party control. For details, refer to: migrating resumes.

Usage:

First, reference the DLL file of htmlagilitypack.UsingHtmlagilitypack;

Functions that extract content based on XPath: 

 
 ///     <Summary>  

  ///  Obtain filtered strings Based on xpath

  ///     </Summary>  

  ///     <Param name = "content">  HTML content to be extracted  </Param>  

 ///     <Param name = "XPath">  XPath expressions  </Param>  

  ///     <Param name = "separ">  Delimiter  </Param>  

  ///     <Returns>  Extracted content </Returns>  
  
  Public     Static     String  Getstrbyxpath (  String  Content,  String  XPath,  String  Separ)

{

Htmldocument doc1  =    New  Htmldocument ();

Doc1.loadhtml (content );

Htmlnodecollection repeatnodes  =  Doc1.documentnode. selectnodes (XPath );

  String  Text  =     ""  ;

  //  Cyclic nodes  
  
 Foreach  (Htmlnode Node  In  Repeatnodes)

{

Text  + =  Node. innertext  +  Separ;

}

  Return  Text;

}