private void Ws_RegisterCompleted(object sender, selling.RegisterCompletedEventArgs e)
        {
            var callDialog = new AlertDialog.Builder(this);
            callDialog.SetTitle("Notify");
            callDialog.SetMessage(e.Result.Message);
            callDialog.SetNeutralButton("Ok", delegate {

            });
             callDialog.Show();
        }
        private void Ws_LoginCompleted(object sender, selling.LoginCompletedEventArgs e)
        {
            string msg = "";
             if (e.Result.UserID.ToString().Equals("0"))
            {
                msg = e.Result.Message;

            }
            else
            {
                msg = "You login with id:" + e.Result.UserID;
            }
            var callDialog = new AlertDialog.Builder(this);
            callDialog.SetTitle("Notify");
            callDialog.SetMessage(msg);
            callDialog.SetNeutralButton("Ok", delegate {

            });
            callDialog.Show();
        }