为什么这个错误捕捉不到呀？ApplicationException

private static bool InitCom(string m_port, int m_baudrate)
        {
            ss_port.PortNum = m_port;
            ss_port.BaudRate = m_baudrate;
            ss_port.ByteSize = 8;
            ss_port.Parity = 0;
            ss_port.StopBits = 1;
            ss_port.ReadTimeout = 1000;
            try
            {
                if (ss_port.Opened)
                {
                    ss_port.Close();
                    ss_port.Open();
                }
                else
                {
                  ss_port.Open();//打开串口
                }
                return true;
            }
            catch (Exception e)
            {
                ClassMain.writeLog("错误：" + e.Message, 0);
                return false;
            }        }
提示：在 System.ApplicationException 中第一次偶然出现的“123321.exe”类型的异常弄得我到程序老自动退出去，急啊！