Reputation: 33
I want to from a xhtml string to extract everything inside heading tags (i.e h1,h2,h3 etc) to then use in a sidemenu.
The xhtml string will have numbered headings so a h2 will be something like "1.1 Heading", and under that a h3 with "1.1.1 Heading" and 1.1.2 and so on.
<div class="main-body">
<h2>1.1 Heading</h2>
<h3>1.1.1 Subheading</h3>
<p>Lorem ipsum</p>
<h3>1.1.2 Another Subheading</h3>
<p>Lorem ipsum</p>
<h2>2.1 Heading</h2>
<h3>2.1.1 Subheading</h3>
<p>Lorem ipsum</p>
<h4>2.1.1.1 SubSubHeading</h4>
</div>
Above is an example of how the html will look like, so I want to group togheter the parent (h2) with it's children (h3, h4) and when a new h2 is found in the DOM I want to make a new group containing it's "children".
Upvotes: 2
Views: 2851
Reputation: 9771
You have two ways to retrieve all text inside <h1>
to <h6>
tag
So your input html is:
string input = @"<div class='main - body'>
<h2> 1.1 Heading </h2>
<h3> 1.1.1 Subheading </h3>
<p> Lorem ipsum </ p >
<h3> 1.1.2 Another Subheading</h3>
<p> Lorem ipsum </p>
<h2> 2.1 Heading </h2>
<h3> 2.1.1 Subheading </h3>
<p> Lorem ipsum </p>
<h4> 2.1.1.1 SubSubHeading </h4>
</div> ";
1) By using Regex:
Use this regex to get all text inside heading tag from <h1>
to <h6>
<h[1-6][^>]*?>(?<TagText>.*?)</h[1-6]>
Usage:
string pattern = @"<h[1-6][^>]*?>(?<TagText>.*?)</h[1-6]>";
MatchCollection matches = Regex.Matches(input, pattern);
var heading_matches = matches.Cast<Match>().Select(x => x.Groups["TagText"].Value);
To neglect h1
then use
string pattern = @"<h[2-6][^>]*?>(?<TagText>.*?)</h[2-6]>";
2) By using HtmlAgilityPack:
Use HtmlAgilityPack pack to retrieve all text inside <h1>
to <h6>
.
You need to install this package from NuGet Package Manager Console.
Install-Package HtmlAgilityPack -Version 1.8.14
Usage:
var htmlDocument = new HtmlDocument();
htmlDocument.LoadHtml(input);
string xpathQuery = "//*[starts-with(name(),'h') and string-length(name()) = 2 and number(substring(name(), 2)) <= 6]";
var texts = htmlDocument.
DocumentNode
.SelectNodes(xpathQuery)
.Select(x => x.InnerText)
.ToList();
To neglect h1
then use
string xpathQuery = "//*[starts-with(name(),'h') and string-length(name()) = 2 and number(substring(name(), 2)) > 1 and number(substring(name(), 2)) <= 6]";
Output: (From Debugger)
Upvotes: 4