How to send a byte array to a serial device (C#)

Question

I have a serial device which sends me a string of ASCII Hex codes (e.g. 42 33). I then read these in and use them to bit rotate a checksum. Once they have been rotated I need to send them back to the serial device including some control bytes.

I feel my code may be overcomplicated and I am struggling to create a clean way to build a series of bytes to send back to the device.

// Calculate Checksum
private byte[] calcChecksum(string checksum)
{
    // Create a byte array from checksum string
    byte[] byteArray = Encoding.ASCII.GetBytes(checksum);

    // Create Hex Characters from ASCII codes of byte array positions 5, 6.
    string left = ((char)byteArray[5]).ToString();
    string right = ((char)byteArray[6]).ToString();

    // Convert Hex Characters to Integer values used for the shifting
    int numLeft = Convert.ToByte(left, 16);
    int numRight = Convert.ToByte(right, 16);

    // Dummy checksum values to shift
    string cs = ShiftLeft(0x5232, numLeft).ToString("x4");
    string kw = ShiftRight(0xab23, numRight).ToString("x4");

    string cskw = cs + kw;

    byte[] checksumBytes = Encoding.ASCII.GetBytes(cskw);

    return checksumBytes;
}

// Communicate with Serial device
private void bChecksum_Click(object sender, EventArgs e)
{
    // Read string from device. Need a better way to create this
    // instead of using a richtext box. Okay for now but suggestions
    // welcome.
    returnCode = tbOutput.Text;
    byte[] checksumBytes = calcChecksum(returnCode);

    // Bytes I need to send to the device. Here I need to insert all the
    // checksumBytes Array values between 0x1B and 0x03
    byte[] bytesToSend = { 0x04, 0x02, 0x31, 0x30, 0x1B, ...array bytes..., 0x03 };
    _serialPort.Write(bytesToSend, 0, bytestosend.Length);
}

To clarify I need a way to insert the checksumBytes Array into the bytesToSend Array in between the 0x1B and 0x03 positions.

Additionally any code improvements would be most welcome.

What exactly is your question? "Make this code more clean"? — CodeCaster
– CodeCaster, Commented Jun 29, 2016 at 8:19
@CodeCaster Sorry, I have edited the question to clarify what I am after. — PiotrG
– PiotrG, Commented Jun 29, 2016 at 8:44
you want to insert checksumBytes to bytesToSend. Am I right? — sowjanya attaluri
– sowjanya attaluri, Commented Jun 29, 2016 at 8:48

Rhys Jones · Accepted Answer · 2016-06-29 09:04:05Z

1

If I've understood you correctly then you could use the Array.CopyTo method to merge 3 arrays together; byte[] controlStart = { 0x01, 0x02, 0x03 }; byte[] checksumBytes = { 0x04, 0x05, 0x06 }; byte[] controlEnd = { 0x07, 0x08, 0x09 };

        byte[] bytesToSend = new byte[controlStart.Length + checksumBytes.Length + controlEnd.Length];

        controlStart.CopyTo(bytesToSend, 0);
        checksumBytes.CopyTo(bytesToSend, controlStart.Length);
        controlEnd.CopyTo(bytesToSend, controlStart.Length + checksumBytes.Length);

answered Jun 29, 2016 at 9:04

Rhys Jones

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1 Comment

PiotrG Over a year ago

Perfect! Thank you!

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