How to use HTML Agility pack

Question

I want to know how to use the HTML Agility Pack as I am totally new to it. My XHTML document is not completely valid. Thats why i wanted to use it. Can any one tell me how to use it in my project? My project is in C#.

Answer 1

if you're just trying to parse your document into something easy to process this is a handy extension method that uses HTML Agility pakc under the hood:

http://vijay.screamingpens.com/archive/2008/05/26/linq-amp-lambda-part-3-html-agility-pack-to-linq.aspx

Answer 2

1. Download and build the HTMLAgilityPack solution.

2. In your application, add a reference to HTMLAgilityPack.dll in the HTMLAgilityPack\Debug (or Realease) \bin folder.

Then, as an example:

    HtmlAgilityPack.HtmlDocument htmlDoc = new HtmlAgilityPack.HtmlDocument();

    // There are various options, set as needed
    htmlDoc.OptionFixNestedTags=true;

    // filePath is a path to a file containing the html
    htmlDoc.Load(filePath);

    // Use:  htmlDoc.LoadXML(xmlString);  to load from a string

   // ParseErrors is an ArrayList containing any errors from the Load statement
   if (htmlDoc.ParseErrors!=null && htmlDoc.ParseErrors.Count>0)
   {
       // Handle any parse errors as required

   }
   else
   {

        if (htmlDoc.DocumentNode != null)
        {
            HtmlNode bodyNode = htmlDoc.DocumentNode.SelectSingleNode("//body");

            if (bodyNode != null)
            {
                // Do something with bodyNode
            }
        }
    }

(NB: This code is an example only and not necessarily the best/only approach. Do not use it blindly in your own application.)

The HtmlDocument.Load() method also accepts a stream which is very useful in integrating with other stream oriented classes in the .NET framework. While HtmlEntity.DeEntitize() is another useful method for processing html entities correctly. (thanks Matthew)

HtmlDocument and HtmlNode are the classes you'll use most. Similar to an XML parser, it provides the selectSingleNode and selectNodes methods that accept XPath expressions.

Pay attention to the HtmlDocument.Option?????? boolean properties. These control how the Load and LoadXML methods will process your HTML/XHTML.

There is also a compiled help file called HtmlAgilityPack.chm that has a complete reference for each of the objects. This is normally in the base folder of the solution.

Answer 3

I dont know if this will be of any help to you but I have written a couple of articles which introduce the basics.

• http://runtingsproper.blogspot.com/2009/09/htmlagilitypack-article-series.html
• http://runtingsproper.blogspot.com/2009/09/introduction-to-htmlagilitypack-library.html
• http://runtingsproper.blogspot.com/2009/11/easily-extracting-links-from-snippet-of.html

The next article is 95% complete, I just have to write up explanations of the last few parts of the code I have written. If you are interested then I will try to remember to post here when I publish it.

Answer 4

I've posted a sample code on my blog. http://www.fairnet.com/post/2010/08/28/Html-screen-scraping-with-HtmlAgilityPack-Library.aspx