如何使用正则表达式C＃避免在自定义HTML标签之间插入HTML标签

Question

I have a requirement, in which the

'<H3></H3>'

HTML Tag count needs to be found using RegEx C#.

The following code finds the H3 Tag count correctly, provided, if there is no custom HTML Tags in between(ie, contains text or string alone).

 var regexHeading = new Regex(@"<h3>(.*?)</h3>"); 

Whereas, if the Heading Tag contains any custom HTML Tag, then the above RegEx is not working as expected. [Ex: <h3><a></a></h3>].

Can anyone suggest, which is the best method to find HTML Tag count using Regular expression c#(even if it contains any custom tags in between).

Partial Solution(maybe helpful for someone): I wrote one custom tag, but it is not working in all the scenarios

Answer 1

Parsing html using regex is not recommended, there are many answer about it in stackoverflow.

Use HtmlAgilityPack instead.

Example: Try this: HtmlDocument doc = new HtmlDocument(); doc.Load("file.htm"); var h3nodes = doc.DocumentElement.SelectNodes("//body//h3"]; HtmlDocument doc = new HtmlDocument(); doc.Load("file.htm"); var h3nodes = doc.DocumentElement.SelectNodes("//body//h3"];

or var h3nodes = doc.DocumentElement.Descendants("h3");

h3nodes is a node list of html elements with tag "h3".

For "SelectNodes" method parameters, please read about XPath.

Answer 2

If you are just looking to count the number of matches of <H3> elements then you will only need to match the opening element.

If you need to ensure that the element is well formed and has a matching close tag then your current RegEx should work. If you can tell us what you are expecting and the results you are getting then it will help us give you a better answer.

Answer 3

Thanks Ethan Brown :-) The hint you had given resolved my issue.

The Regex is not able to find the

 

 
 


  
 
  
  
 
   
<H3>/n</H3>
 
  

 

 
 

So, I tried replacing the New line tag with empty string as shown below

publishingPageContent = publishingPageContent.Replace("\n", string.Empty);
var regexHeading = new Regex(@"<h3>(.*?)</h3>");
//Find matching                                        
var matchHeadings = regexHeading.Matches(publishingPageContent);

Thanks guyz for helping me in figuring out this issue. !:)