partial void btnOne(NSObject sender)
        {
            if (connection != null && connection.State == TCConnectionState.Connected)
            {
                connection.SendDigits("1");

                Console.WriteLine("send digits: 1");
            }
        }
 partial void UIButton7_TouchUpInside(UIButton sender)
 {
     if (_connection != null && _connection.State == TCConnectionState.Connected)
     {
         _connection.SendDigits("1");
     }
 }