read HTML tag text

Question

Hi All,

I would like to get the following output from htm ot html files:

1. MY WEBSITE (Means to get text between TITLE tags)

2. left (Means to align values of "p" tag)

3. boat.gif (Means to src values of "img" tag)

<!DOCTYPE html>

<html>

<HEAD>

<TITLE>MY WEBSITE</TITLE>

<7HEAD>

<body>

<h1>My First Heading</h1>

<p align="left">My first paragraph.</p>

</body>

</html>

Thanks Allot in Advance

Darma

Vulpes · Answer

If you have multiple tags, you can do: string regExp3 = @" MatchCollection mc = Regex.Matches(html, regExp3); foreach(Match m in mc) Console.WriteLine(m.Groups[1].Value);

darma teja · Answer

Hi Vulpes, If i have more than one image, how can get all images with their path. Thanks, Darma

Raj Bandi · Answer

Hi,

Im not sure why it wasn't working for you. HtmlAgilityPack is well tested and is fast.

Here is the code

static void Main(string[] args)
{

var doc = new HtmlDocument();
doc.Load("e:\\temp\\dharma.html");

string align = string.Empty,src = string.Empty,title = string.Empty;

var titleNode = doc.DocumentNode.SelectSingleNode("//title");
if(titleNode != null)
{
title = titleNode.InnerText;
}

var p = doc.DocumentNode.SelectSingleNode("//p[@align]");
if(p != null)
{
align = p.Attributes["align"].Value;
}
var img = doc.DocumentNode.SelectSingleNode("//img[@src]");
if(img != null)
{
src = img.Attributes["src"].Value;
}

Console.WriteLine(title);
Console.WriteLine(align);
Console.WriteLine(src);
}

darma teja · Answer

Hi Vulpes and Raj, Thanks for the replies. @Vulpes: Perfectly, It is working. @ Raj: First I tried with " HtmlAgilityPack", Unfortunately it was not working. Thanks, Darma

Raj Bandi · Answer

Hmm,

Sorry my bad incorrectly interpreted, I thought it was on the client side in browser, so you want read this in C#,

Use HtmlAgilityPack http://htmlagilitypack.codeplex.com/, add references to your project.

var doc = new HtmlDocment();
doc.load("yourfile.htm");

Use xpath queries something like this
var p = doc.DocumentElement.SelectNodes("//p[@align]");

Vulpes · Answer

Here's a different approach using regular expressions.

As I don't know what type of application you're writing, I've used a console application for illustration:

using System;

using System.IO;

using System.Text.RegularExpressions;

class Test

{

static void Main()

{

string html = File.ReadAllText("darma.html");

string regExp1 = "<TITLE>(.*?)</TITLE>";

string title = Regex.Match(html, regExp1).Groups[1].Value;

Console.WriteLine(title);

string regExp2 = @"<p align=""(.*?)"">";

string align = Regex.Match(html, regExp2).Groups[1].Value;

Console.WriteLine(align);

string regExp3 = @"<img src=""(.*?)""";

string img = Regex.Match(html, regExp3).Groups[1].Value;

Console.WriteLine(img);

Console.ReadKey();

}

}

The output, as expected, is:

MY WEBSITE

left

boat.gif

darma teja · Answer

Hi Raj, Thanks for the reply. Which class I should use to load my html file by giving file path. Thanks Darma

Raj Bandi · Answer

//MY WEBSITE

var title = document.title;

//left value, Note: without an id, get p first element, with id use document.getElementById
var align = document.getElementsByTagName("p")[0].getAttribute("align");

//boat.gif
var src = document.getElementsByTagName("img")[0].getAttribute("src");

Call above scripts when dom is ready i,e. either call a function on body load or include above script between </body> and </html> tags(when all the dom elements are processed).

Hope this helps,

Cheers,
Raj