关闭.Net 2.0中的SerialPort时出现ObjectDisposedException

我有一个C#windows窗体应用程序，它通过COM端口与USB加密狗通信。我使用.Net 2.0中的SerialPort类进行通信，串行端口对象在应用程序的整个生命周期内都是打开的。应用程序向设备发送命令，还可以从设备接收未经请求的数据。

我的问题发生在表单关闭时-不幸的是，我在试图关闭COM端口时（随机地）得到了一个ObjectDisposedException

System.ObjectDisposedException was unhandled

Message=Safe handle has been closed
  Source=System
  ObjectName=""
  StackTrace:
       at Microsoft.Win32.UnsafeNativeMethods.SetCommMask(SafeFileHandle hFile, Int32 dwEvtMask)
       at System.IO.Ports.SerialStream.Dispose(Boolean disposing)
       at System.IO.Ports.SerialStream.Finalize()
  InnerException: 

我发现了有类似问题的人发来的帖子，并尝试了变通方法[此处][1]

[1] ：http://zachsaw.blogspot.com/2010/07/net-serialport-woes.html尽管这是针对IOException的，并且没有停止问题。

我的Close（）代码如下：

        public void Close()
    {
        try
        {
            Console.WriteLine("******ComPort.Close - baseStream.Close*******");
            baseStream.Close();
        }
        catch (Exception ex)
        {
            Console.WriteLine("******ComPort.Close baseStream.Close raised exception: " + ex + "*******");
        }
        try
        {
            _onDataReceived = null;
            Console.WriteLine("******ComPort.Close - _serialPort.Close*******");
            _serialPort.Close();
        }
        catch (Exception ex)
        {
            Console.WriteLine("******ComPort.Close - _serialPort.Close raised exception: " + ex + "*******");
        }            
    }

我的日志记录显示，执行从未超过尝试关闭SerialPort的BaseStream（这是在第一个try块中），所以我尝试删除这一行，但异常仍然会定期抛出——第二个try块中的日志记录出现，然后异常发生。两个catch块都没有捕获异常。

有什么想法吗？

更新-添加完整类：

    namespace My.Utilities
{
    public interface ISerialPortObserver
    {
        void SerialPortWriteException();
    }
    internal class ComPort : ISerialPort
    {
        private readonly ISerialPortObserver _observer;
        readonly SerialPort _serialPort;
        private DataReceivedDelegate _onDataReceived;
        public event DataReceivedDelegate OnDataReceived
        {
            add { lock (_dataReceivedLocker) { _onDataReceived += value; } }
            remove { lock (_dataReceivedLocker) { _onDataReceived -= value; } }            
        }
        private readonly object _dataReceivedLocker = new object();
        private readonly object _locker = new object();
        internal ComPort()
        {         
            _serialPort = new SerialPort { ReadTimeout = 10, WriteTimeout = 100, DtrEnable = true };
            _serialPort.DataReceived += DataReceived;
        }
        internal ComPort(ISerialPortObserver observer) : this()
        {
            _observer = observer;         
        }
        private void DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            DataReceivedDelegate temp = null;
            lock (_locker)
            {
                lock (_dataReceivedLocker)
                {
                    temp = _onDataReceived;
                }
                string dataReceived = string.Empty;
                var sp = (SerialPort) sender;
                try
                {
                    dataReceived = sp.ReadExisting();
                }
                catch (Exception ex)
                {
                    Logger.Log(TraceLevel.Error, "ComPort.DataReceived raised exception: " + ex);
                }
                if (null != temp && string.Empty != dataReceived)
                {
                    try
                    {
                        temp(dataReceived, TickProvider.GetTickCount());
                    }
                    catch (Exception ex)
                    {
                        Logger.Log(TraceLevel.Error, "ComPort.DataReceived raised exception calling handler: " + ex);
                    }
                }
            }
        }
        public string Port
        {
            set
            {
                try
                {
                    _serialPort.PortName = value;
                }
                catch (Exception ex)
                {
                    Logger.Log(TraceLevel.Error, "ComPort.Port raised exception: " + ex);
                }
            }
        }
        private System.IO.Stream comPortStream = null;
        public bool Open()
        {
            SetupSerialPortWithWorkaround();
            try
            {
                _serialPort.Open();
                comPortStream = _serialPort.BaseStream;
                return true;
            }
            catch (Exception ex)
            {
                Logger.Log(TraceLevel.Warning, "ComPort.Open raised exception: " + ex);
                return false;
            }
        }
        public bool IsOpen
        {
            get
            {
                SetupSerialPortWithWorkaround();
                try
                {
                    return _serialPort.IsOpen;
                }
                catch(Exception ex)
                {
                    Logger.Log(TraceLevel.Error, "ComPort.IsOpen raised exception: " + ex);
                }
                return false;
            }
        }
        internal virtual void SetupSerialPortWithWorkaround()
        {
            try
            {
                //http://zachsaw.blogspot.com/2010/07/net-serialport-woes.html
                // This class is meant to fix the problem in .Net that is causing the ObjectDisposedException.
                SerialPortFixer.Execute(_serialPort.PortName);
            }
            catch (Exception e)
            {
                Logger.Log(TraceLevel.Info, "Work around for .Net SerialPort object disposed exception failed with : " + e + " Will still attempt open port as normal");
            }
        }
        public void Close()
        {
            try
            {
                comPortStream.Close();
            }
            catch (Exception ex)
            {
                Logger.Log(TraceLevel.Error, "ComPortStream.Close raised exception: " + ex);
            }
            try
            {
                _onDataReceived = null;
                _serialPort.Close();
            }
            catch (Exception ex)
            {
                Logger.Log(TraceLevel.Error, "ComPort.Close raised exception: " + ex);
            }            
        }
        public void WriteData(string aData, DataReceivedDelegate handler)
        {
            try
            {
                OnDataReceived += handler;
                _serialPort.Write(aData + "'r'n");
            }
            catch (Exception ex)
            {
                Logger.Log(TraceLevel.Error, "ComPort.WriteData raised exception: " + ex);                
                if (null != _observer)
                {
                    _observer.SerialPortWriteException();
                }
            }
        }
    }    
}