Serial Port.Datareceived 未触发（.net 4.5）

Question

我正在使用 .net 4.5，因为我了解到一些互联网上关于 .net 对 rad 串行数据的代码实现错误的讨论，所以我使用了下面的代码。

问题是，尽管我可以看到我创建了一个 COM 端口连接（到正确的 COM 端口号），但它永远不会在收到数据时触发。 数据接收基于一个简单的 Arduino 应用程序（Arduino 监视器确实显示数据通过串行发送），但 .net 永远不会在串行事件时触发。

我在 eventread 上设置了断点，它永远不会被命中

我在这里查看过其他讨论，例如.NET SerialPort DataReceived event not firing，但到目前为止，他们还没有解决我遇到的问题。我尝试了串行线设置的各种组合，并相信以下是正确的。 至于 Arduino 部分，该行设置为：

Serial.begin(9600);

我将我的班级称为：`InfraredSensor mySens = new InfraredSensor("COM4",9600);'

class InfraredSensor
{
    private string Eventlogapp = "IRlogging"; 
    private SerialPort Port;
    public InfraredSensor(string COMport, int baudrate) //constructor
    {
        if (applicationlog != "") this.EventlogSapec = applicationlog;
        WriteEventLog(EventlogSapec, EventSource, "Initializing-IR:" + COMport, info, EventIRStarted);

        // I found that the .net standard implementation for com port reading is not OK (.net doesnt follow win32 api).
        // There are numerous readings about it, but a good way to read seams to be to use Serial BaseStream.ReadAsync
        // code below is based upon : http://www.c-sharpcorner.com/code/2880/serial-port-with-efficient-data-reading-in-c-sharp.aspx

        this.comport = COMport;
        SerialPort Port = new SerialPort(comport);

        Port.BaudRate = baudrate;
        Port.DataBits = 8;
        Port.Parity = Parity.None;
        Port.StopBits = StopBits.One;
        Port.Handshake = Handshake.None;

        Port.NewLine = Environment.NewLine;
        Port.ReceivedBytesThreshold = 2; // + linefeed 
        Port.DataReceived += ReadEvent;
        Port.Open();
        Port.DtrEnable = true;
       // i've tested from here i do have an open connection
       // its just dat ReadEvent never fires...
    }


      private void ReadEvent(object sender, SerialDataReceivedEventArgs e)
    {
        byte[] buffer = new byte[2];//todo i only send "A" or "B", for the debug moment 
        Action kickoffRead = null;

        kickoffRead = (Action)(() => Port.BaseStream.BeginRead(buffer, 0, buffer.Length, delegate (IAsyncResult ar)
        {
            try
            {
                int count = Port.BaseStream.EndRead(ar);
                byte[] dst = new byte[count];
                Buffer.BlockCopy(buffer, 0, dst, 0, count);
                RaiseAppSerialDataEvent(dst);
            }
            catch (Exception ex)
            {
                WriteEventLog(Eventlogapp, "IR", "Failure-IR:" + ex.Message, info, 204);
            }
            kickoffRead();
        }, null)); kickoffRead();
    }

    private void RaiseAppSerialDataEvent(byte[] Data)
    {
    // code never gets to here
        string msg = Encoding.Default.GetString(Data);
    int breakpointhere = 0;

        if (msg.Contains('A')) WriteEventLog(Eventlogapp, "IR", "Sensor A", info, 213);

        if (msg.Contains('B')) WriteEventLog(Eventlogapp, "IR", "Sensor B", info, 214);


    }
}

我的想法已经用完了（头发让我发疯了）是什么导致了这种行为？

Answer 1

最后这花了我 2 天的时间......

在我现在使用的 arduino 代码中

serial.print("Mytext\n");  // using \n to be sure of escape character

对于我现在使用的串行线路配置

this.comport = COMport;
this.Port = new SerialPort(comport);
this.Port.BaudRate = baudrate;
this.Port.DataBits = 8;
this.Port.Parity = Parity.None;
this.Port.StopBits = StopBits.One;
this.Port.Handshake = Handshake.None;
this.Port.RtsEnable = true;
      //  Port.NewLine = "\n";
       //   Port.ReceivedBytesThreshold = 2; // + linefeed 
        this.Port.DataReceived += new new SerialDataReceivedEventHandler(ReadEvent);

....
..
SerialDataReceivedEventHandler(ReadEvent);
//code didnt change inside but the method has changed see the +=

Answer 2

DataReceived 事件在有数据通过串行端口时触发，但它可以随机触发。因此，您可以在一个事件中获得部分消息，而在另一个事件中获得另一半消息。你应该有某种密钥来知道你什么时候有完整的消息。所以建立你的字符串，直到你有整个消息然后根据消息做一些事情。

例如，当有换行时，我的设备的消息就完成了。所以我的代码看起来像：

char ESC = (char)27;
char CR = (char)13;
char LF = (char)10;
StringBuilder sb = new StringBuilder();

private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
    string Data = serialPort1.ReadExisting();

    foreach (char c in Data)
    {
        if (c == LF)
        {
            sb.Append(c);

            //we have our message, do something, maybe like
            if (sb.ToString().Contains("A"))
            {
                //print A
            }
            else
            {
                //print B
            }
        }
        else
        {
            sb.Append(c);
        }
    }
}