void _port_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            StringBuilder sb = new StringBuilder();

            if (_asciimode)
            {
                for (int i = 0; i < _port.BytesToRead; i++)
                {
                    sb.Append((char)_port.ReadChar());
                }
            }
            else
            {
                for (int i = 0; i < _port.BytesToRead; i++)
                {
                    sb.Append(_port.ReadByte());
                    sb.Append(" ");
                }
            }

            Dispatcher.BeginInvoke(new Action(delegate
            {
                TbRecieve.AppendText(sb.ToString());
                TbRecieve.ScrollToEnd();
            }));
        }
 private void BtnClearRec_Click(object sender, RoutedEventArgs e)
 {
     TbRecieve.Clear();
 }