using System.Net.WebRequest;

WebRequest request = WebRequest.Create("http://www.yahoo.co.jp");
WebResponse response = request.GetResponse();

Stream ReceiveStream = response.GetResponseStream();

StreamReader readStream = new StreamReader(ReceiveStream, Encoding.UTF8);

Byte[] buffer = new Byte[response.ContentLength];
readStream.Read(buffer, 0, response.ContentLength);

response.Close();