Reading ftdi to show string

Question

I use this code to read the RFID chip SN through ftdi usb reader. I want to use the RFID SN (0DBFFC21) later in SQL queries.

My problem is that I get the SN many times splited in two rows... How should I put there a delay or something, so I can get full string everytime?

    #region Namespace Inclusions
using System;
using System.IO.Ports;
using System.Windows.Forms;
#endregion

namespace SerialPortExample
{
  class SerialPortProgram
  {
    // Create the serial port with basic settings
    private SerialPort port = new SerialPort("COM1",
      9600, Parity.None, 8, StopBits.One);

    [STAThread]
    static void Main(string[] args)
    { 
      // Instatiate this class
      new SerialPortProgram();
    }

    private SerialPortProgram()
    {
      Console.WriteLine("Incoming Data:");

      // Attach a method to be called when there
      // is data waiting in the port's buffer
      port.DataReceived += new 
        SerialDataReceivedEventHandler(port_DataReceived);

      // Begin communications
      port.Open();

      // Enter an application loop to keep this thread alive
      Application.Run();
    }

    private void port_DataReceived(object sender,
      SerialDataReceivedEventArgs e)
    {
      // Show all the incoming data in the port's buffer
      Console.WriteLine(port.ReadExisting());
    }
  }
}

Answer 1

The correct approach may vary, but here is one simple to read data of known size:

string _buffer;

void port_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    _buffer += port.ReadExisting(); // read into buffer
    if (_buffer.Length > 7) // wait until at least 8 characters are received
    {
        Console.WriteLine(_buffer.Substring(0, 8)); // display
        _buffer = _buffer.Substring(8, _buffer.Length - 8); // remove from buffer
    }
}

if delay between packets is big enough following code may be sufficient:

    _buffer += port.ReadExisting();
    if (_buffer.Length >= 8)
    {
        Console.WriteLine(_buffer);
        _buffer = null;
    }