c# – 等待来自串行端口的响应,然后发送下一个数据

我正在从.bin文件中读取字节数据并将整个字节数据拆分成16-16字节的帧,所以我希望逐个16字节的帧并等到第一帧完成它的循环.

SerialPort类的回调方法：

private void port_DataReceived(object sender,SerialDataReceivedEventArgs e)
{

    // Read data from serial port:
    byte[] buffer = new byte[serialPort.BytesToRead];
    serialPort.Read(buffer,buffer.Length);
    StringBuilder sb = new StringBuilder();
    List<string> response = new List<string>();
    for (int i = 0; i < buffer.Length; i++)
    {
        string currentByte = string.Format("{0:X2}",buffer[i]);
        response.Add(currentByte);

        sb.AppendFormat("{0:X2}",buffer[i]);
    }

    string responesCode = response[1].ToString();
    if (responesCode == "44")
    {
        // Wait until the first response is not received
        foreach (var packet in packetList.Skip(1))
        {
            // This method which sending the the data
            this.ReadByteDataFromFile(packet);
        }
    }
}

FdbrowseFile_Click按钮单击：

private void FdbrowseFile_Click(object sender,RoutedEventArgs e)
{
    Microsoft.Win32.OpenFileDialog dlg = new Microsoft.Win32.OpenFileDialog();
    Nullable<bool> result = dlg.ShowDialog();
    if (result == true)
    {
        byte[] fileBytes = File.ReadAllBytes(filename);

        foreach (byte[] copySlice in fileBytes.Slices(16))
        {
            var splitedByteArray = copySlice;
            if (splitedByteArray.Length != 16)
            {
                byte[] padd = new byte[16];
                var startAt = 0;
                Array.copy(splitedByteArray,padd,startAt,splitedByteArray.Length);
                packetList.Add(padd);
            }
            else
            {
                packetList.Add(splitedByteArray);
            }
        }
        ReadByteDataFromFile(packetList[0]);
    }
}

ReadByteDataFromFile方法：

public void ReadByteDataFromFile(byte[] packet) {
 try {
  byte[] mBuffer = new byte[24];
  byte[] payload = new byte[16];
  int i = 0;
  foreach(var bytes in packet) {
   payload[i++] = bytes;
  }
  CheckSumHelper checkSumHelper = new CheckSumHelper();
  var ckSum = checkSumHelper.GetCheckSum(payload);
  mBuffer[0] = 0x02;
  mBuffer[1] = 0x10;
  mBuffer[2] = CheckSumHelper.GetBytesFromDecimal(packet[0]);
  mBuffer[3] = CheckSumHelper.GetBytesFromDecimal(packet[1]);
  mBuffer[4] = CheckSumHelper.GetBytesFromDecimal(packet[2]);
  mBuffer[5] = CheckSumHelper.GetBytesFromDecimal(packet[3]);
  mBuffer[6] = CheckSumHelper.GetBytesFromDecimal(packet[4]);
  mBuffer[7] = CheckSumHelper.GetBytesFromDecimal(packet[5]);
  mBuffer[8] = CheckSumHelper.GetBytesFromDecimal(packet[6]);
  mBuffer[9] = CheckSumHelper.GetBytesFromDecimal(packet[7]);
  mBuffer[10] = CheckSumHelper.GetBytesFromDecimal(packet[8]);
  mBuffer[11] = CheckSumHelper.GetBytesFromDecimal(packet[9]);
  mBuffer[12] = CheckSumHelper.GetBytesFromDecimal(packet[10]);
  mBuffer[13] = CheckSumHelper.GetBytesFromDecimal(packet[11]);
  mBuffer[14] = CheckSumHelper.GetBytesFromDecimal(packet[12]);
  mBuffer[15] = CheckSumHelper.GetBytesFromDecimal(packet[13]);
  mBuffer[16] = CheckSumHelper.GetBytesFromDecimal(packet[14]);
  mBuffer[17] = CheckSumHelper.GetBytesFromDecimal(packet[15]);
  mBuffer[18] = 0x17;
  mBuffer[19] = 0x00;
  mBuffer[20] = 0x00;
  mBuffer[21] = 0x00;
  mBuffer[22] = Convert.ToByte(int.Parse(ckSum,System.Globalization.NumberStyles.Hexnumber));
  mBuffer[23] = 0x03;
  serialPort.Write(mBuffer,mBuffer.Length);
 } catch (Exception ex) {
  ExceptionHandler exceptionHandler = new ExceptionHandler();
  exceptionHandler.HandleException(ex);
 }
}

我如何为ReadByteDataFromFile方法添加延迟？

解决方法

在写完第一帧后,在循环中等待完整响应.

// Set read timeout to value recommended in the communication protocol specification 
// so serial port operations don't stuck.
_port.WriteTimeout = 200;
_port.ReadTimeout = 200;

public void OnClick()
{
    // Write first frame.
    _port.Write(...);
    // Now wait for the full response.

    // Expected response length. Look for the constant value from the device communication 
    // protocol specification or extract from the response header (first response bytes) if  
    // there is any specified in the protocol.
    int count = ...; 
    var buffer = new byte[count];
    var offset = 0;
    while (count > 0)
    {
        var readCount = _port.Read(buffer,offset,count);                 
        offset += readCount;
        count -= readCount;
    }
    // Now buffer contains full response or TimeoutException instance is thrown by SerialPort.
    // Check response status code and write other frames.
}

为了不阻止UI线程,您可能仍然需要使用同步API和Task.Run().请参阅有关StackOverflow的C# await event and timeout in serial port communication讨论.

有关更多信息,请查看Kim Hamilton的Top 5 SerialPort Tips文章.