WebClient client = new WebClient();
            Stream stream = client.OpenRead("http://www.vchome.net/dotnet/dotnetdocs/dotnet37.htm");
            FileStream fs = File.Open("a.html", FileMode.Create);
            using (fs)
            {
                using (stream)
                {
                    while (true)
                    {
                        byte[] b = new byte[100];
                        int r = stream.Read(b, 0, b.Length);
                        fs.Write(b, 0, r);
                        if (r < b.Length)
                        {
                            break;
                        }
                    }
                }

            }
            Console.WriteLine("ok");