从HTML页面提取特定文本

Question

Html page is look like this

<tr>
<th rowspan="4" scope="row">General</th>
<td class="ttl"><a href="network-bands.php3">2G Network</a></td>
<td class="nfo">GSM 850 / 900 / 1800 / 1900 </td>
</tr><tr>
<td class="ttl"><a href="network-bands.php3">3G Network</a></td>
<td class="nfo">HSDPA 900 / 1900 / 2100 </td>
</tr>

for that i am try to use

var text = document.getElementsByClassName("nfo")[0].innerHTML;

Provided By Alex

But i am getting this error Error 2 The name 'document' does not exist in the current context C:\\Users\\Nabi Javid\\Documents\\Visual Studio 2008\\Projects\\WpfApplication2\\WpfApplication2\\Window1.xaml.cs 30 22 WpfApplication2

Am i missing some Libary or something

Currently my code is like that

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApplication1
{
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            HtmlAgilityPack.HtmlDocument htmlDoc = new HtmlAgilityPack.HtmlDocument();
            htmlDoc.Load("nokia_c5_03-3578.html");
             var text = document.getElementsByClassName("nfo")[0].innerHTML;

        } 
    }

}

Answer 1

You are mixing C# code with javascript code.

Instead of this:

var text = document.getElementsByClassName("nfo")[0].innerHTML;

type this:

var text = htmlDoc.DocumentNode.SelectNodes("//td[@class='nfo']")[0].InnerHtml;

To keep it simple, I have refrained from checking exceptions.

Answer 2

I'm not very deep into .net but it looks like you are trying to mix JavaScript-code

var text = document.getElementsByClassName("nfo")[0].innerHTML;

with your .net code...?

Answer 3

You can get elements by class name using next method which return elements where are several classes defined in one class attribute:

private HtmlNodeCollection GetElementsByClassName(HtmlDocument htmlDocument, string className)
{
    string xpath =
        String.Format(
            "//*[contains(concat(' ', normalize-space(@class), ' '), ' {0} ')]",
            className);
    return htmlDocument.DocumentNode.SelectNodes(xpath);
}

Answer 4

You must use the htmlDoc variable to call methods in your case. By the way the HtmlDocument class does not have a method with that name. Try to see if you can find another match for your needs in this list .

As the error says, the document variable does not exits in your code.

Answer 5

do you want

var text = htmlDoc.getElementsByClassName("nfo")[0].innerHTML;

? Not familiar with HTML Agility Pack, but that would seem to make sense