Text.IsValidCardNumber Method

public static bool IsValidCardNumber(string cardNumber)
 {
     cardNumber = cardNumber.Replace(" ", "");
     int[] doubledDigits = new int[cardNumber.Length / 2];
     int k = 0;
     for (int i = cardNumber.Length - 2; i >= 0; i -= 2)
     {
         int digit = int.Parse(cardNumber[i].ToString());
         doubledDigits[k] = digit * 2;
         k++;
     }
     int total = 0;
     foreach (int i in doubledDigits)
     {
         string number = i.ToString();
         for (int j = 0; j < number.Length; j++)
             total += int.Parse(number[j].ToString());
     }
     int total2 = 0;
     for (int i = cardNumber.Length - 1; i >= 0; i -= 2)
     {
         int digit = int.Parse(cardNumber[i].ToString());
         total2 += digit;
     }
     int final = total + total2;
     return final % 10 == 0;
 }