Close串口后再重新Open串口，报出“对端口的访问被拒绝”，这显然是之前关串口没有关掉，重复打开了，为什么会这样？解决思路

Close串口后再重新Open串口，报出“对端口的访问被拒绝”，这显然是之前关串口没有关掉，重复打开了，为什么会这样？
在软件中，在串口的Data_Received事件中若发生了异常，将相应操作杆线程关闭，关掉串口，再重新打开串口，再重新打开。在打开串口的时候会报异常“对端口的访问被拒绝”。这显然是之前关串口没有关掉，重复打开了，为什么会这样？

  private void CloseJoystickerRightport()

        {

            try

            {

                while (JoystickerLexium23dPort.IsOpen)

                {

                    joyStickRightPortKeepReading = false;

                    JoystickerLexium23dPort.DataReceived -= new SerialDataReceivedEventHandler(JoystickerRightport_DataReceived);

                    JoystickerLexium23dPort.DiscardOutBuffer();

                    JoystickerLexium23dPort.DiscardInBuffer();

                    JoystickerLexium23dPort.Close();  

                }

            }

            catch (System.Exception ex)

            {

                writeExceptionToLogFile("CloseXYZJoystickRightport", ex.Message);

            }

        }

private void OpenJoystickRightPot()

{

            try

            {

                //if (JoystickerLexium23dPort.IsOpen)

                //{

                while (JoystickerLexium23dPort.IsOpen) JoystickerLexium23dPort.Close();

                if (!JoystickerLexium23dPort.IsOpen) JoystickerLexium23dPort.Open();

                //}

                //else

                //{

                //    JoystickerLexium23dPort.Open();

                //}

                JoystickerLexium23dPort.DiscardOutBuffer();

                JoystickerLexium23dPort.DiscardInBuffer();

                JoystickerLexium23dPort.WriteTimeout = 100;

                JoystickerLexium23dPort.ReadTimeout = 100;  //**操作杆一发送命令,即使没有动操作杆,也会返回值  //MJ

                JoystickerLexium23dPort.DataReceived += new SerialDataReceivedEventHandler(JoystickerRightport_DataReceived);

}

}

catch(Exception ex)

{

   writeExceptionToLogFile("OpenXYZJoystickRightport", ex.Message);

}

------解决方案--------------------
private void OpenJoystickRightPot()
{
            try
            {
                //if (JoystickerLexium23dPort.IsOpen)
                //{
                while (JoystickerLexium23dPort.IsOpen) JoystickerLexium23dPort.Close();
                if (!JoystickerLexium23dPort.IsOpen) JoystickerLexium23dPort.Open();
                //}
                //else
                //{
                //    JoystickerLexium23dPort.Open();