HttpResponse

You can use HttpWebRequest class to open HTTP connection to a specific URL and to get response in form of HttpWebResponse instance.

After that you can inspect HTTP response status, headers and response body using HttpWebResponse.

Here is a sample code regarding these classes that I've written for another thread today:
using System.Net;
using System;
using System.IO;

namespace ExceptionTest
{

    class Program
    {

        static void Main(string[] args)
        {

            try
            {

                HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create("http://www.google.com/search?hl=en&source=hp&biw=1680&bih=917&q=search+something&oq=search+something&aq=f&aqi=g7g-v3&aql=&gs_sm=e&gs_upl=2820l4595l0l4723l16l11l0l3l3l1l231l1188l2.4.2l8l0");
                HttpWebResponse resp = (HttpWebResponse)req.GetResponse();

                string html = null;

                if (resp.StatusCode == HttpStatusCode.OK)
                {
                    using (StreamReader reader = new StreamReader(resp.GetResponseStream()))
                        html = reader.ReadToEnd();
                }

                Console.WriteLine(html);

            }
            catch (System.Exception ex)
            {
                Console.WriteLine(ex.Message);
            }

            Console.WriteLine("Press ENTER to continue...");
            Console.ReadLine();
        }

    }
}

The original thread is:
http://www.c-sharpcorner.com/Forums/Thread/135011/find-text-in-web-page.aspx

Zoran