how to write and read to serialPort in same time?

Question

I have some device that i need to make a connection using SerialPort. This device receiving commands from my side and also sending data to me. I doing all the send/receive in same class => same thread.

I have been connected to this device and i succeed to send/receive command and data from/to this device.

One of the command that i need to send every 25 milliseconds is 'give me your status' - that mean that i asking the device to send be back some struct with data.

In case i missing some receiving data ... when i doing 'serialPortStream.BytesToRead' ( test if there are some data to get ) will i find on my ByteReading the older buffer that i did not rad yet ? how many packages i will have there in case i missed the last package that i needed to read or maybe the new data received will delete the old data that alread received before ?

Answer 1

Use an OnRecieveData handler that saves the data to a ConcurrentQueue or something similar.

namespace Test
{   class Program
    {
        const int bufSize = 2048;
        static void Main(string[] args)
        {

            Byte[] buf = new Byte[bufSize]; 
            SerialPort sp = new SerialPort("COM1", 115200);
            sp.DataReceived += port_OnReceiveData; // Add DataReceived Event Handler

            sp.Open();

            // Wait for data or user input to continue.
            Console.ReadLine();


            sp.Close();
        }

        private static void port_OnReceiveData(object sender,  SerialDataReceivedEventArgs e)
        {
            SerialPort port = (SerialPort) sender;
            switch(e.EventType)
            {
                case SerialData.Chars:
                {
                    Byte[] buf = new Byte[bufSize];
                    port.Read(buf, 0, bufSize)
                    Console.WriteLine("Recieved data! " + buf.ToString());
                    break;
                }
                case SerialData.Eof:
                {
                    // means receiving ended
                    break;
                }
            }
        }
    }
}