Simple Web Crawler in C# to get Html content

 WebRequest request = WebRequest.Create("http://google.com/");//Type url here
        using (WebResponse response = request.GetResponse())
        {
            using (StreamReader responseReader =
              new StreamReader(response.GetResponseStream()))
            {
                string responseData = responseReader.ReadToEnd();
              string path=  Server.MapPath(".");
                if(!File.Exists(path+"//Asptrick.html"))
                File.Create(path+"//Asptrick.html");
                using (StreamWriter writer =
                  new StreamWriter(path + "//Asptrick.html")) //Where You Want to save Content
                {
                    writer.Write(responseData);
                }
            }
        }

use namespace for this as following:
using System.IO;
using System.Net;