两个 .NET 线程和硬件访问的问题

我正在创建一个通过 FT2232H USB/RS232 转换器与设备通信的应用程序。为了进行通信，我使用 FTDI 网站上的 FTD2XX_NET.dll 库。
我正在使用两个线程：

接收者线程

        private void receiverLoop()
        {
            if (this.DataReceivedHandler == null)
            {
                throw new BackendException("dataReceived delegate is not set");
            }

            FTDI.FT_STATUS ftStatus = FTDI.FT_STATUS.FT_OK;
            byte[] readBytes = new byte[this.ReadBufferSize];

            while (true)
            {
                lock (FtdiPort.threadLocker)
                {
                    UInt32 numBytesRead = 0;

                    ftStatus = ftdiDevice.Read(readBytes, this.ReadBufferSize, ref numBytesRead);

                    if (ftStatus == FTDI.FT_STATUS.FT_OK)
                    {
                        this.DataReceivedHandler(readBytes, numBytesRead);
                    }
                    else
                    {
                        Trace.WriteLine(String.Format("Couldn't read data from ftdi: status {0}", ftStatus));
                        Thread.Sleep(10);
                    }                    
                }
                Thread.Sleep(this.RXThreadDelay);

            }
        }

编写从主线程调用的函数

    public void Write(byte[] data, int length)
    {
        if (this.IsOpened)
        {
            uint i = 0;

            lock (FtdiPort.threadLocker)
            {
                this.ftdiDevice.Write(data, length, ref i);
            }

            Thread.Sleep(1);
            if (i != (int)length)
            {
                throw new BackendException("Couldnt send all data");
            }
        }
        else
        {
            throw new BackendException("Port is closed");
        }
    }

另一种方法是使用 FTDI 的事件通知机制，这样您就不需要阻塞线程来读取数据：

public FTDISample()
{
    private AutoResetEvent receivedDataEvent;
    private BackgroundWorker dataReceivedHandler;
    private FTDI ftdi;

    public FTDISample(string serialNumber){
        ftdi = new FTDI();
        FTDI.FT_STATUS status = ftdi.OpenBySerialNumber(serialNumber);
        receivedDataEvent = new AutoResetEvent(false);
        status = mFTDI.SetEventNotification(FTDI.FT_EVENTS.FT_EVENT_RXCHAR, receivedDataEvent);
        dataReceivedHandler = new BackgroundWorker();
        dataReceivedHandler.DoWork += ReadData;
        if (!dataReceivedHandler.IsBusy)
        {
            dataReceivedHandler.RunWorkerAsync();
        }
    }

    private void ReadData(object pSender, DoWorkEventArgs pEventArgs)
    {
        UInt32 nrOfBytesAvailable = 0;
        while (true)
        {
            // wait until event is fired
            this.receivedDataEvent.WaitOne();

            // try to recieve data now
            FTDI.FT_STATUS status = ftdi.GetRxBytesAvailable(ref nrOfBytesAvailable);
            if (status != FTDI.FT_STATUS.FT_OK)
            {
                break;
            }
            if (nrOfBytesAvailable > 0)
            {
                byte[] readData = new byte[nrOfBytesAvailable];
                UInt32 numBytesRead = 0;
                status = mFTDI.Read(readData, nrOfBytesAvailable, ref numBytesRead);

                // invoke your own event handler for data received...
                //InvokeCharacterReceivedEvent(fParsedData);
            }
        }
    }

    public bool Write(string data)
    {
        UInt32 numBytesWritten = 0;
        ASCIIEncoding enconding = new ASCIIEncoding();
        byte[] bytes = enconding.GetBytes(data);
        FTDI.FT_STATUS status = ftdi.Write(bytes, bytes.Length, ref numBytesWritten);
        if (status != FTDI.FT_STATUS.FT_OK)
        {
            Debug.WriteLine("FTDI Write Status ERROR: " + status);
            return false;
        }
        if (numBytesWritten < data.Length)
        {
            Debug.WriteLine("FTDI Write Length ERROR: " + status + " length " + data.Length +
                            " written " + numBytesWritten);
            return false;
        }
        return true;
    }