C# 多次接收到串行端口数据

我正在开发一个winforms应用程序，它可以与FPGA设备通信。由于该设备仍在开发中，我尝试使用com0com（）和另一个winforms应用程序作为模拟器来模拟它

我正在从我的应用程序向模拟器发送一个44字节的字节数组：

CC AA 01 28 09 2A 0C 00 01 FF 00 FA 02 FF 01 5E 03 FF 01 C2 04 FF 02 26 05 FF 02 8A 06 FF 02 EE 07 FF 03 52 08 FF 03 B6 09 FF 04 1A

前4个字节是标头，第4个字节包含要跟随的字节数。在这种情况下，40=0x28。API规范中没有终止值。以下是我如何处理DataReceived事件：

void comPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    int byte_count = 0;
    int read_count = 0;
    while (comPort.BytesToRead > 0)
    {
        byte_count = comPort.BytesToRead;
        byte[] byteTemp = new byte[byte_count];
        read_count = comPort.Read(byteTemp, 0, byte_count);
    }
    byte[] byteBuffer = new byte[read_count];
    int intNumBytes2read = byteBuffer[3];

    // do other stuff
}

我的问题是，当事件触发时，模拟器并不总是接收整个有效负载。事实上，每次我从应用程序向模拟器发送数据时，事件通常会触发不止一次。我对这个问题的研究表明，这是一个常见的问题，我需要创建某种排队机制。以我有限的C#经验，我正在努力理解如何做到这一点

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任何建议都将不胜感激。

您需要一个状态机来跟踪您在接收消息方面取得的进展。可以这样看：

private int state;
private byte[] payload;
private int payloadIndex;

private void comPort_DataReceived(object sender, SerialDataReceivedEventArgs e) {
    while (comPort.BytesToRead > 0) {
        byte b = (byte)comPort.BaseStream.ReadByte();
        switch (state) {
            case 0: 
                if (b == 0xcc) state++;
                else protocolViolation("Bad header, expected 0xcc");
                break;
            case 1:
                if (b == 0xaa) state++;
                else protocolViolation("Bad header, expected 0xaa");
                break;
            case 2:
                if (b == 0x01) state++;
                else protocolViolation("Bad header, expected 0x01");
                break;
            case 3:
                payload = new byte[b];
                payloadIndex = 0;
                state++;
                break;
            case 4:
                payload[payloadIndex++] = b;
                if (payloadIndex == payload.Length) {
                    processPayload(payload);
                    state = 0;
                }
                break;
        }
    }
}

private void protocolViolation(string why) {
    state = 0;
    Debug.WriteLine(why);
}

private void processPayload(byte[] payload) {
    // etc..
}

---

您需要一个状态机来跟踪您在接收消息方面取得的进展。可以这样看：

private int state;
private byte[] payload;
private int payloadIndex;

private void comPort_DataReceived(object sender, SerialDataReceivedEventArgs e) {
    while (comPort.BytesToRead > 0) {
        byte b = (byte)comPort.BaseStream.ReadByte();
        switch (state) {
            case 0: 
                if (b == 0xcc) state++;
                else protocolViolation("Bad header, expected 0xcc");
                break;
            case 1:
                if (b == 0xaa) state++;
                else protocolViolation("Bad header, expected 0xaa");
                break;
            case 2:
                if (b == 0x01) state++;
                else protocolViolation("Bad header, expected 0x01");
                break;
            case 3:
                payload = new byte[b];
                payloadIndex = 0;
                state++;
                break;
            case 4:
                payload[payloadIndex++] = b;
                if (payloadIndex == payload.Length) {
                    processPayload(payload);
                    state = 0;
                }
                break;
        }
    }
}

private void protocolViolation(string why) {
    state = 0;
    Debug.WriteLine(why);
}

private void processPayload(byte[] payload) {
    // etc..
}