在插入和输出C＃中自动检测Arduino状态

Question

I am trying to create an application that communicates with the arduino and want to cover for issues like plugging out and in of the arduino device when the application is running. I would like it to continue receiving data from the arduino as soon it is plugged back in.

This is the error i get: An unhandled exception of type 'System.IO.IOException' occurred in System.dll

Additional information: The I/O operation has been aborted because of either a thread exit or an application request.

This is the code from which i have tried but it

  private bool AutoDetectArduino()
    {
        ManagementScope connectionscope = new ManagementScope();

        SelectQuery serialQuery = new SelectQuery("SELECT * FROM Win32_SerialPort");

        ManagementObjectSearcher searcher = new ManagementObjectSearcher(connectionscope, serialQuery);

        bool weturn = false;

        try
        {

            foreach (ManagementObject item in searcher.Get())
            {
                string desc = item["Description"].ToString();
                string deviceid = item["DeviceID"].ToString();

                if (desc.Contains("USB Serial Device"))
                {
                    sp.Close();
                    sp.PortName = deviceid;

                    weturn = true;
                }
                else
                {
                    weturn = false;
                }
            }

        }
        catch (ManagementException e)
        {

        }

        return weturn;
    }

    string[] generalarray = new string[3];

    public void readArduinoLightData()
    {
        AutoDetectArduino();
        try
        {
            if (!sp.IsOpen)
            {
                sp.Open();
            }

            sp.Parity = Parity.None;
            sp.StopBits = StopBits.One;
            sp.Handshake = Handshake.None;

            sp.ReadTimeout = 10000;

            sp.DataReceived += new SerialDataReceivedEventHandler(datareceive);
        }
        catch
        {

        }
    }


    private void datareceive(object sender, SerialDataReceivedEventArgs e)
    {

            for (count = 0; count < generalarray.Length; count++)
            {
                generalarray[count] = sp.ReadLine();
            }

            temperature =Convert.ToDouble(generalarray[0]);
            light = Convert.ToDouble(generalarray[1]);
            currentvolt = Convert.ToDouble(generalarray[2]);
        }

// I have created a timer that keeps on checking if the ports from the Auto Detect method but can't get it right. Does any one have a clue on this, Thank You !!

Answer 1

You are entirely at the mercy of the driver that sits between your application and the hardware connection. Some drivers handle the sudden removal better than others. For the drivers that do not fail gracefully, there is no amount of try/catching you can do to catch this reliably.

The issue occurs when data is being read while the underlying basestream is still open. There are workarounds for this particular issue but again, you will still be at the mercy of the driver.

If you are interested in capturing USB insertion and removal events without polling, checkout my project here https://github.com/corytodd/porty . This listens to messages on the process message pump and handles them accordingly.