Example: Protocol configuration in event mode

An example of a NetLogic contained in the serial

Port

object that uses the event mode to read data sent asynchronously from a device. The

OnClick

method, linked to the button pressing event, enables you to stop the current reading and start a new reading.

To use the event mode, you must set the

Timeout

property to

. This way,

ReadBytes

will be blocking as long as the requested data do not arrive on the serial port.

You can stop the reading with the

CancelRead

method, or the

method. In both cases, a

ReadCanceledException

exception is generated. To carry out a clean close of the NetLogic, you must terminate any pending read operations by calling the

method in the NetLogic

Stop

You can download a sample project from SerialPortDemoEventMode.zip.

public class RuntimeNetlogic1 : BaseNetLogic
{
    private SerialPort serialPort;
    private LongRunningTask task;
    public override void Start()
    {
        serialPort = (SerialPort)Owner;
        serialPort.Timeout = TimeSpan.FromMilliseconds(0.0);
        task = new LongRunningTask(Run, Owner);
        task.Start();
    }
    [ExportMethod]
    public void OnClick()
    {
        // Cancel current read
        serialPort.CancelRead();
        task.Cancel();
        // Start new read
        task = new LongRunningTask(Run, Owner);
        task.Start();
    }
    private void Run()
    {
        while(!task.IsCancellationRequested)
        {
            try
            {
                // Block until 3 bytes arrive on serial
                var result = serialPort.ReadBytes(3);
                foreach (var b in result)
                    Log.Info(String.Format("0x{0:x2}", b));
            }
            catch (ReadCanceledException ex)
            {
                // In case of read canceled, exit from the loop
                Log.Info(ex.Message);
                return;
            }
            catch (Exception e)
            {
                Log.Error(e.Message);
            }
        }
    }
    public override void Stop()
    {
        // Explicit call to Close to cancel pending read (if any)
        serialPort.Close();
        task.Cancel();
    }
}

Serial Port API

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