using System;

using System.Linq;

public class Program

{

    static String input = "010203040506070809";

    public static void Main()

    {

        byte[] data = StringToByteArray(input);

        foreach (byte b in data) {

            Console.Write("0x{0:X2}, ", b);

        }

    }

​

    public static byte[] StringToByteArray(string hex) {

        return Enumerable.Range(0, hex.Length)

                         .Where(x => x % 2 == 0)

                         .Select(x => Convert.ToByte(hex.Substring(x, 2), 16))

                         .ToArray();

    }

}