.Net Com口通信编程例子

        private string _sComPortNumber;
        private bool _bFoundPortNumber;
        private System.Windows.Forms.Control _oStaticShow;
        private System.IO.Ports.SerialPort _oCIMControler;

        /// <summary>
        /// COM口名
        /// </summary>
        public string ComPortName { get { return _sComPortNumber; } }
        /// <summary>
        /// 编码
        /// </summary>
        public Encoding StringEncoding { get; set; }
        /// <summary>
        /// 比特率
        /// </summary>
        public int BaudRate { get; set; }
        /// <summary>
        /// 数据位
        /// </summary>
        public int DataBits { get; set; }
        /// <summary>
        /// 奇偶检验
        /// </summary>
        public System.IO.Ports.Parity Parity { get; set; }
        /// <summary>
        /// 停止位
        /// </summary>
        public System.IO.Ports.StopBits StopBits { get; set; }

        private bool OpenPortAndSendMsg()
        {
            foreach (string tmpName in System.IO.Ports.SerialPort.GetPortNames())
            {
                foreach (string sCurrentMachinePortNumber in System.IO.Ports.SerialPort.GetPortNames())
                {
                    try
                    {
                        if (_bFoundPortNumber == false)
                        {
                            System.IO.Ports.SerialPort otmpsp = new System.IO.Ports.SerialPort();
                            otmpsp.DataReceived += new System.IO.Ports.SerialDataReceivedEventHandler(otmpsp_DataReceived);
                            otmpsp.PortName = sCurrentMachinePortNumber;
                            otmpsp.BaudRate = this.BaudRate;
                            otmpsp.DataBits = this.DataBits;
                            otmpsp.Parity = this.Parity;
                            otmpsp.StopBits = this.StopBits;
                            otmpsp.Open();

                            //写数据************************
                            otmpsp.Write(new byte[] { 2 }, 0, 1);
                            string Command = "ST";
                            otmpsp.Write(Command);
                            otmpsp.Write(new byte[] { 3 }, 0, 1);
                            otmpsp.Write(new byte[] { 6 }, 0, 1);
                            otmpsp.Write(new byte[] { 5 }, 0, 1);
                            //****************************

                            System.Threading.Thread.Sleep(500);

                            otmpsp.Close();
                        }
                        else
                        {
                            return true;
                        }
                    }
                    catch (Exception ex)
                    {
                    }
                }
            }
            return false;
        }

        void otmpsp_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
        {
            System.IO.Ports.SerialPort oSenderObject = sender as System.IO.Ports.SerialPort;
            if (oSenderObject.BytesToWrite > 0)
            {
                oSenderObject.BaseStream.Flush();
            }
            int iReadFlag = oSenderObject.BytesToRead;
            while (iReadFlag > 0)
            {
                string sReturn = oSenderObject.ReadExisting();
                if (sReturn.Contains(""))
                {
                    _bFoundPortNumber = true;
                    _sComPortNumber = oSenderObject.PortName;
                }
                iReadFlag = oSenderObject.BytesToRead;
            }
        }