Send string with non-ascii characters out serial port c#

Question

So, I'm attempting to communicate with a device over a serialport object in C#. The device is looking for a mask value to be sent to it as a part of a command string. For example, one of the strings will be something like "SETMASK:{}", where {} is the unsigned 8-bit mask.

When I use a terminal (such as BRAY) to communicate with the device, I can get the device to work. For example, in BRAY terminal, the string SETMASK:$FF will set the mask to 0xFF. However, I can't for the life of me figure out how to do this in C#.

I've already tried the following function, where Data is the mask value and CMD is the surrounding string ("SETMASK:" in this case"). Where am I going wrong?

public static string EmbedDataInString(string Cmd, byte Data)
    {
        byte[] ConvertedToByteArray = new byte[(Cmd.Length * sizeof(char)) + 2];
        System.Buffer.BlockCopy(Cmd.ToCharArray(), 0, ConvertedToByteArray, 0, ConvertedToByteArray.Length - 2);

        ConvertedToByteArray[ConvertedToByteArray.Length - 2] = Data;

        /*Add on null terminator*/
        ConvertedToByteArray[ConvertedToByteArray.Length - 1] = (byte)0x00;

        Cmd = System.Text.Encoding.Unicode.GetString(ConvertedToByteArray);

        return Cmd;
    }

Answer 1

Can't be certain, but I'll bet your device is expecting 1-byte chars, but the C# char is 2 bytes. Try converting your string into a byte array with Encoding.ASCII.GetBytes(). You'll probably also need to return the byte[] array instead of a string, since you'll end up converting it back to 2 byte chars.

using System.Text;

// ...

public static byte[] EmbedDataInString(string Cmd, byte Data)
{
    byte[] ConvertedToByteArray = new byte[Cmd.Length + 2];
    System.Buffer.BlockCopy(Encoding.ASCII.GetBytes(Cmd), 0, ConvertedToByteArray, 0, ConvertedToByteArray.Length - 2);

    ConvertedToByteArray[ConvertedToByteArray.Length - 2] = Data;

    /*Add on null terminator*/
    ConvertedToByteArray[ConvertedToByteArray.Length - 1] = (byte)0x00;

    return ConvertedToByteArray;
}

If your device accepts some other character encoding, swap out ASCII for the appropriate one.

Answer 2

Problem solved, the System.Buffer.BlockCopy() command was embedding zeroes after each character in the string. This works:

public static byte[] EmbedDataInString(string Cmd, byte Data)
    {
        byte[] ConvertedToByteArray = new byte[(Cmd.Length * sizeof(byte)) + 3];
        char[] Buffer = Cmd.ToCharArray();

        for (int i = 0; i < Buffer.Length; i++)
        {
            ConvertedToByteArray[i] = (byte)Buffer[i];
        }

        ConvertedToByteArray[ConvertedToByteArray.Length - 3] = Data;
        ConvertedToByteArray[ConvertedToByteArray.Length - 2] = (byte)0x0A;
        /*Add on null terminator*/
        ConvertedToByteArray[ConvertedToByteArray.Length - 1] = (byte)0x00;

        return ConvertedToByteArray;
    }