Question

I have a structure in c# with two members:

public int commandID;  
public string MsgData;  

I need to turn both these into a single byte array which then gets sent to a C++ program that will unpack the bytes , it will grab the first `sizeof(int) bytes to get the commandID and then the rest of the MsgData will get used.

What is a good way to do this in c# ?

Answer 1

The following will just return a regular array of bytes, with the first four representing the command ID and the remainder representing the message data, ASCII-encoded and zero-terminated.

static byte[] GetCommandBytes(Command c)
{
    var command = BitConverter.GetBytes(c.commandID);
    var data = Encoding.UTF8.GetBytes(c.MsgData);
    var both = command.Concat(data).Concat(new byte[1]).ToArray();
    return both;
}

You can switch out Encoding.UTF8 for e.g. Encoding.ASCII if you wish – as long as your C++ consumer can interpret the string on the other end.