Problem converting C# code into kernel code for OpenCL

I'm trying to make my C# code a kernel code that can be executed using OpenCL, Here is my current code:

kernel void Execute() {    ulong start;    ulong stop;    start = 1;    stop = 10000000000000000001;    do {        byte[] pass = Encoding.ASCII.GetBytes(start.ToString());        Key key = new Key(pass, 32, true);        BitcoinSecret bs = new BitcoinSecret(key, Network.Main);        PubKey pb = bs.PubKey;        BitcoinAddress bitcoinAddress = pb.GetAddress(ScriptPubKeyType.Legacy,            Network.Main);        Console.WriteLine(start +" | " + bitcoinAddress);        start++;    } while (start != stop);}

But it keeps giving me error that string is not identified (i changed that later to:) and byte is not identified, I don't know what to do and tried searching everywhere.