Question

Assume there is a string hexString = "0x12" or "0x45" etc. How can I convert the string to another byte[] as below. Thanks.

byte[] myByte = new byte[2];
myByte[0] = 0x1;
myByte[1] = 0x2;

or

myByte[0] = 0x4;
myByte[1] = 0x5;

When I try to concatenate the substring as below,

myByte[0] = '0x' + '4'; // Show compile error. It doesn't work.

I don’t know how to fix it. thanks.
etc.

Answer 1

Are looking for something like this?

string hex = "0123456789abcdef";

string input = "0x45";
Debug.Assert(Regex.Match(input, "^0x[0-9a-f]{2}$").Success);

byte[] result = new byte[2];
result[0] = (byte)hex.IndexOf(input[2]);
result[1] = (byte)hex.IndexOf(input[3]);

// result[0] == 0x04
// result[1] == 0x05