HttpWebRequest Login

        private void button1_Click(object sender, EventArgs e)
        {
            CookieContainer cookieCon = new CookieContainer();
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://www.elitepvpers.com/forum/login.php?do=login");
            request.Method = "POST";
            request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; rv:8.0) Gecko/20100101 Firefox/8.0";
            request.ContentType = "application/x-www-form-urlencoded";
            string post = "vb_login_username=EPVP_USERNAME&vb_login_password=EPVP_PASSWORT&cookieuser=1&s=&securitytoken=guest&do=login&vb_login_md5password=&vb_login_md5password_utf=";
            ASCIIEncoding encoding = new ASCIIEncoding();
            byte[] byteArr = Encoding.UTF8.GetBytes(post);
            request.ContentLength = byteArr.Length;
            Stream dataStream = request.GetRequestStream();
            dataStream.Write(byteArr, 0, byteArr.Length);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            StreamReader reader = new StreamReader(response.GetResponseStream());
            string Quelltext = reader.ReadToEnd();
            if (Quelltext.Contains("Logout"))
            {
                MessageBox.Show("Eingeloggt!", "Login Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            else
            {
                MessageBox.Show("Nicht eingeloggt!", "Login Message", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }