Can I use HttpClient (C#) to parse HTML pages?

HttpClient in C# is primarily used for sending HTTP requests and receiving HTTP responses from a web service or a web page. It doesn't have built-in capabilities to parse HTML content. However, you can use HttpClient to fetch the HTML content as a string, and then you can use another library like HtmlAgilityPack to parse and manipulate the HTML.

Here's a basic example of how you can use HttpClient to fetch HTML content and then parse it with HtmlAgilityPack:

using System;
using System.Net.Http;
using System.Threading.Tasks;
using HtmlAgilityPack;

class Program
{
    static async Task Main(string[] args)
    {
        var url = "http://example.com"; // Replace with your target URL

        using (var httpClient = new HttpClient())
        {
            try
            {
                // Fetch the HTML content from the URL
                var html = await httpClient.GetStringAsync(url);

                // Load HTML into HtmlDocument
                var htmlDoc = new HtmlDocument();
                htmlDoc.LoadHtml(html);

                // Now you can use HtmlAgilityPack to query the document
                foreach (var node in htmlDoc.DocumentNode.SelectNodes("//a[@href]"))
                {
                    // Extract the href attribute from each <a> tag
                    Console.WriteLine($"Link: {node.Attributes["href"].Value}");
                }
            }
            catch (HttpRequestException e)
            {
                // Handle any web request exceptions if they occur
                Console.WriteLine("\nException Caught!");
                Console.WriteLine("Message :{0} ", e.Message);
            }
        }
    }
}

In this example, HttpClient.GetStringAsync is used to asynchronously fetch the HTML content from a web page as a string. The HtmlDocument instance from HtmlAgilityPack is then used to load the HTML content. Once loaded, you can use various methods provided by HtmlAgilityPack to query and manipulate the HTML DOM.

To use HtmlAgilityPack, you need to add it to your project. You can do this via NuGet Package Manager with the following command:

Install-Package HtmlAgilityPack

Please note that web scraping could be against the terms of service of some websites. Always check the website's terms of service and /robots.txt to ensure that you are allowed to scrape it, and be respectful of the website's resources.