using System;

public class Program {

    public static void Main()

    {   

        gerar(81030, 123456);

    }

​

    public static void gerar(int valor, int codigo) {

        char[] arr = new char[8];

​

        int v = Convert.ToInt32(valor); 

​

        arr[0] = (char)(codigo >> 24); 

        arr[1] = (char)((codigo >> 16) & 0xFF);

        arr[2] = (char)((codigo >> 8) & 0xFF);

        arr[3] = (char)((v >> 8) & 0xFF);

        arr[4] = (char)(v & 0xFF);

​

        Console.WriteLine("arr[0]: " + arr[0]);

        Console.WriteLine("arr[1]: " + arr[1]);

        Console.WriteLine("arr[2]: " + arr[2]);

        Console.WriteLine("arr[3]: " + arr[3]);

        Console.WriteLine("arr[4]: " + arr[4]);

    }

}

​