C#串口通信—向串口发送数据，同步接收返回数据

最近写C#串口通信程序，系统是B/S架构。SerialPort类有一个DataReceived事件，用来接收串口返回的数据，但这种方式在C/S架构下很好用，但B/S就不好处理了。所以写了一个同步模式接收返回数据的方法，不使用DataReceived事件。经过测试，可以正常使用。

一、MachineFactory类

为什么使用工厂类：售货机由不止一个厂家提供，接口协议都不一样。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;
using System.IO;
using System.IO.Ports;

namespace IMachineDll
{
    /// <summary>
    /// 售货机工厂类
    /// </summary>
    public class MachineFactory
    {
        /// <summary>
        /// 货机接口缓存
        /// </summary>
        private static Dictionary<string, IMachine> dicMachine = new Dictionary<string, IMachine>();
        /// <summary>
        /// 锁变量
        /// </summary>
        public static object _lock = new object();

        /// <summary>
        /// 创建售货机类
        /// </summary>
        /// <param name="path">DLL物理路径</param>
        /// <param name="dllName">DLL名称(不含扩展名)，命名空间必须为DLL名称加“Dll”后缀，类名必须和DLL名称相同</param>
        ///  <param name="com">串口名称，如：COM1</param>
        public static IMachine Create(string path, string dllName, string com)
        {
            if (!dicMachine.ContainsKey(dllName)
                || dicMachine[dllName] == null)
            {
                using (FileStream fs = new FileStream(path + dllName + ".dll", FileMode.Open, FileAccess.Read))
                {
                    using (MemoryStream ms = new MemoryStream())
                    {
                        byte[] byteArray = new byte[];
                        while (fs.Read(byteArray, , byteArray.Length) > )
                        {
                            ms.Write(byteArray, , byteArray.Length);
                        }

                        Assembly assembly = Assembly.Load(ms.ToArray());
                        dicMachine[dllName] = (IMachine)assembly.CreateInstance(dllName + "Dll." + dllName, false, BindingFlags.Default, null, new object[] { com }, null, null);
                    }
                }
            }

            return dicMachine[dllName];
        }
    }
}

二、Machine类

1、变量与构造函数

/// <summary>
/// 串口资源
/// </summary>
private SerialPort serialPort = null;

public Machine(string com)
{
    serialPort = new SerialPort(com, , Parity.None, , StopBits.One);
    serialPort.ReadBufferSize = ;
    serialPort.WriteBufferSize = ;
}

2、向串口发送数据，同步接收返回数据的方法：

/// <summary>
/// 向串口发送数据，读取返回数据
/// </summary>
/// <param name="sendData">发送的数据</param>
/// <returns>返回的数据</returns>
private byte[] ReadPort(byte[] sendData)
{
    lock (MachineFactory._lock)
    {
        //打开连接
        if (!serialPort.IsOpen) serialPort.Open();

        //发送数据
        serialPort.Write(sendData, , sendData.Length);

        //读取返回数据
        DateTime dt = DateTime.Now;
        while (serialPort.BytesToRead == )
        {
            Thread.Sleep();

            if (DateTime.Now.Subtract(dt).TotalMilliseconds > ) //如果5秒后仍然无数据返回，则视为超时
            {
                throw new Exception("主版无响应");
            }
        }
        Thread.Sleep();
        byte[] recData = new byte[serialPort.BytesToRead];
        serialPort.Read(recData, , recData.Length);

        //关闭连接
        if (serialPort.IsOpen) serialPort.Close();

        return recData;
    }
}

优化版：

/// <summary>
/// 向串口发送数据，读取返回数据
/// </summary>
/// <param name="sendData">发送的数据</param>
/// <returns>返回的数据</returns>
private byte[] ReadPort(byte[] sendData)
{
    lock (MachineFactory._lock)
    {
        //打开连接
        if (!serialPort.IsOpen) serialPort.Open();

        //发送数据
        serialPort.Write(sendData, , sendData.Length);

        //读取返回数据
        DateTime dt = DateTime.Now;
        while (serialPort.BytesToRead < )
        {
            Thread.Sleep();

            if (DateTime.Now.Subtract(dt).TotalMilliseconds > ) //如果5秒后仍然无数据返回，则视为超时
            {
                throw new Exception("主版无响应");
            }
        }
        List<byte> recList = new List<byte>();
        byte[] recData = new byte[serialPort.BytesToRead];
        serialPort.Read(recData, , recData.Length);
        recList.AddRange(recData);
        int length = recData[] + ; //报文数据总长度
        while (recList.Count < length)
        {
            if (serialPort.BytesToRead > )
            {
                recData = new byte[serialPort.BytesToRead];
                serialPort.Read(recData, , recData.Length);
                recList.AddRange(recData);
            }
            Thread.Sleep();
        }

        //关闭连接
        if (serialPort.IsOpen) serialPort.Close();

        return recList.ToArray();
    }
}

3、发送联机指令：

/// <summary>
/// 联机
/// </summary>
/// <param name="msg">传出错误信息</param>
/// <returns>联机是否成功</returns>
public bool Connect(out string msg)
{
    byte[] sendData = new byte[] { 0x01, 0x01, 0x00, 0x00 };
    CommonUtil.CalCheckCode(sendData);
    byte[] recData = ReadPort(sendData);

    if (recData.Length >=
        && recData[] == 0x01
        && recData[] == 0x02
        && recData[] == 0x00
        && CommonUtil.ValidCheckCode(recData))
    {
        switch (recData[])
        {
            case 0x00:
                msg = "控制主板正在重启";
                return false;
            case 0x01:
                msg = "联机成功";
                return true;
            case 0x02:
                msg = "控制主板正在维护";
                return false;
            case 0x03:
                msg = "控制主板收到的数据格式不正确";
                return false;
            default:
                msg = "未知状态";
                return false;
        }
    }
    else if (IsRunning(recData, out msg) || !IsConnected(recData, out msg))
    {
        return false;
    }
    else
    {
        throw new Exception("货机返回的数据格式不正确");
    }
}

三、如何使用

1、Controller层代码(还不完善，仅测试，真实情况是根据硬件信息，确定调用哪个Dll使用哪个串口)：

#region 创建售货机接口
/// <summary>
/// 创建售货机接口
/// </summary>
private IMachine CreateMachine()
{
    //return MachineFactory.Create(Request.PhysicalApplicationPath + @"\bin\", "Machine", "COM1");
    return MachineFactory.Create(@"D:\售药机代码\Reception\Machine\bin\Debug\", "Machine", "COM1");
}
#endregion

#region 联机
/// <summary>
/// 联机
/// </summary>
/// <param name="msg">错误信息</param>
/// <returns>联机是否成功</returns>
private bool Connect(out string msg)
{
    try
    {
        IMachine machine = CreateMachine();
        DateTime dt1 = DateTime.Now;
        while (!machine.Connect(out msg))  //联机
        {
            if (DateTime.Now.Subtract(dt1).TotalMilliseconds > )
            {
                msg = "联机超时";
                return false;
            }
            Thread.Sleep();
        }

        return true;
    }
    catch (Exception ex)
    {
        msg = ex.Message;
        return false;
    }
}
#endregion

#region 单次联机
/// <summary>
/// 单次联机
/// </summary>
public ActionResult Conn()
{
    string msg = null;
    Dictionary<string, object> dic = null;

    try
    {
        IMachine machine = CreateMachine();

        if (machine.Connect(out msg)) //联机成功
        {
            dic = new Dictionary<string, object>();
            dic["ok"] = true;
            dic["msg"] = "成功";
            return Content(JsonConvert.SerializeObject(dic));
        }
        else
        {
            dic = new Dictionary<string, object>();
            dic["ok"] = false;
            dic["msg"] = "联机失败：" + msg;
            return Content(JsonConvert.SerializeObject(dic));
        }
    }
    catch (Exception ex)
    {
        dic = new Dictionary<string, object>();
        dic["ok"] = false;
        dic["msg"] = "错误：" + ex.Message;
        return Content(JsonConvert.SerializeObject(dic));
    }
}
#endregion

#region 联机并使能硬纸币器
/// <summary>
/// 联机并使能硬纸币器
/// </summary>
public ActionResult ConnectEnable()
{
    string msg = null;
    Dictionary<string, object> dic = null;

    try
    {
        IMachine machine = CreateMachine();

        if (Connect(out msg) && machine.CoinEnable(out msg) && machine.PaperMoneyEnable(out msg)) //联机并使能硬纸币器成功
        {
            dic = new Dictionary<string, object>();
            dic["ok"] = true;
            dic["msg"] = "成功";
            return Content(JsonConvert.SerializeObject(dic));
        }
        else
        {
            dic = new Dictionary<string, object>();
            dic["ok"] = false;
            dic["msg"] = "硬币器使能失败：" + msg;
            return Content(JsonConvert.SerializeObject(dic));
        }
    }
    catch (Exception ex)
    {
        dic = new Dictionary<string, object>();
        dic["ok"] = false;
        dic["msg"] = "错误：" + ex.Message;
        return Content(JsonConvert.SerializeObject(dic));
    }
}
#endregion

2、前台代码：

@{
    ViewBag.Title = "货机接口测试";
    Layout = null;
}

<!DOCTYPE html>
<html>
<head>
    <title>@ViewBag.Title</title>
    <script type="text/javascript" src="~/Scripts/jquery-1.8.2.min.js"></script>
    <script type="text/javascript" src="~/Scripts/LongPolling.js"></script>
</head>
<body>
    <div style="padding: 20px;">
        <input type="button" value="联机" onclick="connect()" />
        <div style="font-size: 20px; line-height: 30px;">
            <div style="padding: 20px;">
                <span id="msg">&nbsp;</span>
            </div>
        </div>
    </div>
</body>
</html>
<script type="text/javascript">
    //联机
    function connect() {
        commonAjax({
            url: "@Url.Content("/MachineInterface/Conn")",
            callback: function (data) {
                if (data.ok) {
                    var html = "联机成功";
                    $("#msg").html(html);
                }
                else {
                    alert(data.msg);
                }
            }
        });
    }
</script>