SerialPort类

微软在.NET中对串口通讯进行了封装，我们可以在.net2.0及以上版本开发时直接使用SerialPort类对串口进行读写操作。
为操作方便，本文对SerialPort类做了一些封装，暂时取名为SerialPortClient。

SerialPort类的属性主要包括：

串口名称（PortName）
波特率（BaudRate）
数据位 DataBits
停止位 StopBits
奇偶校验 Parity

SerialPort类的事件主要包括：

DataReceived：用于异步接收串口数据事件
ErrorReceived：错误处理事件

SerialPort类的方法主要包括：Open();Close();Read();Write()、DiscardInBuffer()、DiscardOutBuffer()等

参数封装

波特率、数据位这些参数不是系统内置的枚举类型，为方便实际操作需构造波特率、数据位这两个枚举对象。

    #region 波特率、数据位的枚举
    /// <summary>
    /// 串口数据位列表（5,6,7,8）
    /// </summary>
    public enum DataBits : int
    {        
        Five = 5,        
        Six = 6,        
        Sevent = 7,        
        Eight = 8
    }

    /// <summary>
    /// 串口波特率列表。
    /// 75,110,150,300,600,1200,2400,4800,9600,14400,19200,28800,38400,56000,57600,
    /// 115200,128000,230400,256000
    /// </summary>
    public enum BaudRates : int
    {
        BR_75 = 75,
        BR_110 = 110,
        BR_150 = 150,
        BR_300 = 300,
        BR_600 = 600,
        BR_1200 = 1200,
        BR_2400 = 2400,
        BR_4800 = 4800,
        BR_9600 = 9600,
        BR_14400 = 14400,
        BR_19200 = 19200,
        BR_28800 = 28800,
        BR_38400 = 38400,
        BR_56000 = 56000,
        BR_57600 = 57600,
        BR_115200 = 115200,
        BR_128000 = 128000,
        BR_230400 = 230400,
        BR_256000 = 256000
    } 
    #endregion

控件操作封装

对常用的参数下拉列表绑定做一个封装，该操作为封装类的静态方法。
为兼容第三方控件使用IList接口，不直接使用ComboBox类型作为参数。

        #region 静态方法
        /// <summary>
        /// 设置串口号
        /// </summary>
        /// <param name="obj">需要绑定的项的集合（如：ComboBox中项的集合ComboBox.Items）</param>
        public static void SetPortNameValues(IList obj)
        {
            obj.Clear();            
            try
            {                
                foreach (string str in SerialPort.GetPortNames())
                {
                    obj.Add(str);
                }
            }
            catch (Exception e)
            {
                Console.WriteLine("未能查询到串口名称——"+e.ToString());                
            }
            
        }

        /// <summary>
        /// 设置波特率
        /// </summary>
        /// <param name="obj">需要绑定的项的集合（如：ComboBox中项的集合ComboBox.Items）</param>
        public static void SetBauRateValues(IList obj)
        {
            obj.Clear();
            foreach (BaudRates rate in Enum.GetValues(typeof(BaudRates)))
            {
                obj.Add(((int)rate).ToString());
            }
        }

        /// <summary>
        /// 设置数据位
        /// </summary>
        /// <param name="obj">需要绑定的项的集合（如：ComboBox中项的集合ComboBox.Items）</param>
        public static void SetDataBitsValues(IList obj)
        {
            obj.Clear();
            foreach (DataBits databit in Enum.GetValues(typeof(DataBits)))
            {
                obj.Add(((int)databit).ToString());
            }
        }

        /// <summary>
        /// 设置校验位列表
        /// </summary>
        /// <param name="obj">需要绑定的项的集合（如：ComboBox中项的集合ComboBox.Items）</param>
        public static void SetParityValues(IList obj)
        {
            obj.Clear();
            foreach (string str in Enum.GetNames(typeof(Parity)))
            {
                obj.Add(str);
            }
        }

        /// <summary>
        /// 设置停止位
        /// </summary>
        /// <param name="obj">需要绑定的项的集合（如：ComboBox中项的集合ComboBox.Items）</param>
        public static void SetStopBitValues(IList obj)
        {
            obj.Clear();
            foreach (string str in Enum.GetNames(typeof(StopBits)))
            {
                obj.Add(str);
            }
        }
        #endregion

SerialPortClient类实现

该部分代码是SerialPortClient类非静态操作部分的实现，完整的类实现需要加上上面的控件操作封装的实现代码，具体请参照Demo源码。

        #region 变量属性
        public event Action<List<byte>> DataReceived;
        public event SerialErrorReceivedEventHandler ErrorReceived; 

        private SerialPort comPort = new SerialPort();
        private string portName = "COM1";//串口号，默认COM1
        private BaudRates baudRate = BaudRates.BR_9600;//波特率
        private Parity parity = Parity.None;//校验位
        private StopBits stopBits = StopBits.One;//停止位
        private DataBits dataBits = DataBits.Eight;//数据位        

        /// <summary>
        /// 串口号
        /// </summary>
        public string PortName
        {
            get { return portName; }
            set { portName = value; }
        }

        /// <summary>
        /// 波特率
        /// </summary>
        public BaudRates BaudRate
        {
            get { return baudRate; }
            set { baudRate = value; }
        }

        /// <summary>
        /// 奇偶校验位
        /// </summary>
        public Parity Parity
        {
            get { return parity; }
            set { parity = value; }
        }

        /// <summary>
        /// 数据位
        /// </summary>
        public DataBits DataBits
        {
            get { return dataBits; }
            set { dataBits = value; }
        }

        /// <summary>
        /// 停止位
        /// </summary>
        public StopBits StopBits
        {
            get { return stopBits; }
            set { stopBits = value; }
        }             
        #endregion

        #region 构造函数
        /// <summary>
        /// 无参构造函数
        /// </summary>
        public SerialPortClient()
        {
            BoundEvents();
        }

        void BoundEvents()
        {
            comPort.DataReceived += new SerialDataReceivedEventHandler(comPort_DataReceived);
            comPort.ErrorReceived += new SerialErrorReceivedEventHandler(comPort_ErrorReceived);
        }

        /// <summary>
        /// 参数构造函数（使用枚举参数构造）
        /// </summary>
        /// <param name="baud">波特率</param>
        /// <param name="par">奇偶校验位</param>
        /// <param name="sBits">停止位</param>
        /// <param name="dBits">数据位</param>
        /// <param name="name">串口号</param>
        public SerialPortClient(string name, BaudRates baud, Parity par, DataBits dBits, StopBits sBits)
        {
            this.portName = name;
            this.baudRate = baud;
            this.parity = par;
            this.dataBits = dBits;
            this.stopBits = sBits;
            BoundEvents();
        }

        /// <summary>
        /// 参数构造函数（使用字符串参数构造）
        /// </summary>
        /// <param name="baud">波特率</param>
        /// <param name="par">奇偶校验位</param>
        /// <param name="sBits">停止位</param>
        /// <param name="dBits">数据位</param>
        /// <param name="name">串口号</param>
        public SerialPortClient(string name, string baud, string par, string dBits, string sBits)
        {
            this.portName = name;
            this.baudRate = (BaudRates)Enum.Parse(typeof(BaudRates), baud);
            this.parity = (Parity)Enum.Parse(typeof(Parity), par);
            this.dataBits = (DataBits)Enum.Parse(typeof(DataBits), dBits);
            this.stopBits = (StopBits)Enum.Parse(typeof(StopBits), sBits);
            BoundEvents();
       }
        #endregion

        #region 事件处理函数
        /// <summary>
        /// 数据仓库
        /// </summary>
        List<byte> datapool = new List<byte>();//存放接收的所有字节
        /// <summary>
        /// 数据接收处理
        /// </summary>
        void comPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            if (comPort.IsOpen)     //判断是否打开串口
            {

                Byte[] receivedData = new Byte[comPort.BytesToRead];        //创建接收字节数组
                comPort.Read(receivedData, 0, receivedData.Length);         //读取数据

                //触发整条记录的处理
                if (DataReceived != null)
                {
                    datapool.AddRange(receivedData);                
                    DataReceived(datapool);
                }
                
            }
            else
            {
                Console.WriteLine("请打开某个串口", "Error");
            } 
        }
        /// <summary>
        /// 错误处理函数
        /// </summary>
        void comPort_ErrorReceived(object sender, SerialErrorReceivedEventArgs e)
        {
            if (ErrorReceived != null)
            {
                ErrorReceived(sender, e);
            }
        }
        #endregion

        #region 串口关闭/打开
        /// <summary>
        /// 端口是否已经打开
        /// </summary>
        public bool IsOpen
        {
            get
            {
                return comPort.IsOpen;
            }
        }

        /// <summary>
        /// 打开端口
        /// </summary>
        /// <returns></returns>
        public void Open()
        {
            if (comPort.IsOpen) comPort.Close();

            comPort.PortName = portName;
            comPort.BaudRate = (int)baudRate;
            comPort.Parity = parity;
            comPort.DataBits = (int)dataBits;
            comPort.StopBits = stopBits;

            comPort.Open();
        }

        /// <summary>
        /// 关闭端口
        /// </summary>
        public void Close()
        {
            if (comPort.IsOpen) comPort.Close();
        }

        /// <summary>
        /// 丢弃来自串行驱动程序的接收和发送缓冲区的数据
        /// </summary>
        public void DiscardBuffer()
        {
            comPort.DiscardInBuffer();
            comPort.DiscardOutBuffer();
        }
        #endregion

        #region 写入数据
        /// <summary>
        /// 写入数据
        /// </summary>
        /// <param name="buffer"></param>
        public void Write(byte[] buffer, int offset, int count) 
        {
            if (!(comPort.IsOpen)) comPort.Open();
            comPort.Write(buffer,offset, count);
        }

        /// <summary>
        /// 写入数据
        /// </summary>
        /// <param name="buffer">写入端口的字节数组</param>
        public void Write(byte[] buffer)
        {
            if (!(comPort.IsOpen)) comPort.Open();
            comPort.Write(buffer, 0, buffer.Length);
        }
        #endregion

SerialPortClient类使用

SerialPortClient类使用很简单，主要分为初始化下拉列表、初始化串口（绑定数据接收、错误处理事件）两步，在窗体加载事件中调用即可。代码如下：

        //全局变量
        SerialPortClient portClient = new SerialPortClient();
        private void InitPort() 
        {
            portClient.DataReceived+=new Action<List<byte>>(datapool=>
            {
                //匹配数据帧，此处以0xea 0xeb为帧头、0xfa 0xfb为帧尾
                //实际通讯协议应该更复杂
                while (true)
                {
                    if (datapool.Count <4) break;
                    if ((datapool[0] == 0xea) && (datapool[0] == 0xeb)) 
                    {
                        datapool.RemoveAt(0);
                        continue;
                    }
                    int index = -1;//正确作法是记住上次最末尾的索引，避免重复匹配
                    for (int i = 0; i < datapool.Count-1; i++)
                    {
                        if (datapool[i] == 0xfa && datapool[i + 1] == 0xfb) 
                        { 
                            index = i;
                            break;
                        }
                    }
                    if (index != -1)
                    {
                        byte[] data = datapool.GetRange(0, index + 2).ToArray();
                        datapool.RemoveRange(0, index + 2);
                        string msg = Encoding.UTF8.GetString(data,2,data.Length-4);
                        this.BeginInvoke(new Action(() => { textBox_Recive.Text = msg; }));
                    }
                    else break;
                }

            });
        }
        private void InitCmb()
        {
            //绑定端口号
            SerialPortClient.SetPortNameValues(comboBox_Com.Items);
            comboBox_Com.DropDownStyle = ComboBoxStyle.DropDownList;
            comboBox_Com.SelectedIndexChanged += new EventHandler((obj, e) => 
            { 
                if (comboBox_Com.SelectedItem!=null) 
                {
                    portClient.PortName = comboBox_Com.SelectedItem.ToString(); 
                }
            });
            comboBox_Com.SelectedIndex = 0;

            //波特率
            SerialPortClient.SetBauRateValues(comboBox_BaudRates.Items);
            comboBox_BaudRates.DropDownStyle = ComboBoxStyle.DropDownList;
            comboBox_BaudRates.SelectedIndexChanged += new EventHandler((obj, e) => 
            {
                if (comboBox_BaudRates.SelectedItem != null)
                {
                    portClient.BaudRate = (BaudRates)Enum.Parse(typeof(BaudRates), comboBox_BaudRates.SelectedItem.ToString());                    
                }
            });
            comboBox_BaudRates.SelectedIndex = 9;

            //数据位
            SerialPortClient.SetDataBitsValues(comboBox_DataBits.Items);
            comboBox_DataBits.DropDownStyle = ComboBoxStyle.DropDownList;
            comboBox_DataBits.SelectedIndexChanged += new EventHandler((obj, e) =>
            {
                if (comboBox_DataBits.SelectedItem != null)
                {
                    portClient.DataBits = (DataBits)Enum.Parse(typeof(DataBits), comboBox_DataBits.SelectedItem.ToString());
                }
            });
            comboBox_DataBits.SelectedIndex = 3;

            //校验位
            SerialPortClient.SetParityValues(comboBox_Parity.Items);
            comboBox_Parity.DropDownStyle = ComboBoxStyle.DropDownList;
            comboBox_Parity.SelectedIndexChanged += new EventHandler((obj, e) =>
            {
                if (comboBox_Parity.SelectedItem != null)
                {
                    portClient.Parity = (Parity)Enum.Parse(typeof(Parity), comboBox_Parity.SelectedItem.ToString());
                }
            });
            comboBox_Parity.SelectedIndex = 0;

            //停止位
            SerialPortClient.SetStopBitValues(comboBox_StopBits.Items);
            comboBox_StopBits.DropDownStyle = ComboBoxStyle.DropDownList;
            comboBox_StopBits.SelectedIndexChanged += new EventHandler((obj, e) =>
            {
                if (comboBox_StopBits.SelectedItem != null)
                {
                    portClient.StopBits = (StopBits)Enum.Parse(typeof(StopBits), comboBox_StopBits.SelectedItem.ToString());
                }
            });
            comboBox_StopBits.SelectedIndex = 1;
        }

串口的打开、关闭、状态显示等操作请查看文章末尾的Demo源码。