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Credit Card Validator Attribute for ASP.NET MVC 3
/// ASP.NET MVC 3 Credit Card Validator Attribute
/// by Ben Cull - 4 November 2010
///
/// With special thanks to:
/// Thomas @ Orb of Knowledge - http://orb-of-knowledge.blogspot.com/2009/08/extremely-fast-luhn-function-for-c.html
/// For the Extremely fast Luhn algorithm implementation
///
/// And Paul Ingles - http://www.codeproject.com/KB/validation/creditcardvalidator.aspx
/// For a timeless blog post on credit card validation
public class CreditCardAttribute : ValidationAttribute
{
private CardType _cardTypes;
public CardType AcceptedCardTypes
{
get { return _cardTypes; }
set { _cardTypes = value; }
}
public CreditCardAttribute()
{
_cardTypes = CardType.All;
}
public CreditCardAttribute(CardType AcceptedCardTypes)
{
_cardTypes = AcceptedCardTypes;
}
public override bool IsValid(object value)
{
var number = Convert.ToString(value);
if (String.IsNullOrEmpty(number))
return true;
return IsValidType(number, _cardTypes) && IsValidNumber(number);
}
public override string FormatErrorMessage(string name)
{
return "The " + name + " field contains an invalid credit card number.";
}
public enum CardType
{
Unknown = 1,
Visa = 2,
MasterCard = 4,
Amex = 8,
Diners = 16,
All = CardType.Visa | CardType.MasterCard | CardType.Amex | CardType.Diners,
AllOrUnknown = CardType.Unknown | CardType.Visa | CardType.MasterCard | CardType.Amex | CardType.Diners
}
private bool IsValidType(string cardNumber, CardType cardType)
{
// Visa
if (Regex.IsMatch(cardNumber, "^(4)")
&& ((cardType & CardType.Visa) != 0))
return cardNumber.Length == 13 || cardNumber.Length == 16;
// MasterCard
if (Regex.IsMatch(cardNumber, "^(51|52|53|54|55)")
&& ((cardType & CardType.MasterCard) != 0))
return cardNumber.Length == 16;
// Amex
if (Regex.IsMatch(cardNumber, "^(34|37)")
&& ((cardType & CardType.Amex) != 0))
return cardNumber.Length == 15;
// Diners
if (Regex.IsMatch(cardNumber, "^(300|301|302|303|304|305|36|38)")
&& ((cardType & CardType.Diners) != 0))
return cardNumber.Length == 14;
//Unknown
if ((cardType & CardType.Unknown) != 0)
return true;
return false;
}
private bool IsValidNumber(string number)
{
int[] DELTAS = new int[] { 0, 1, 2, 3, 4, -4, -3, -2, -1, 0 };
int checksum = 0;
char[] chars = number.ToCharArray();
for (int i = chars.Length - 1; i > -1; i--)
{
int j = ((int)chars[i]) - 48;
checksum += j;
if (((i - chars.Length) % 2) == 0)
checksum += DELTAS[j];
}
return ((checksum % 10) == 0);
}
}
@bjcull

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bjcull commented Nov 16, 2010

Just added a check to make sure empty values wont fail validation. A required attribute should be used to check for that.

@ruan00151

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ruan00151 commented Jun 16, 2016

Muito bom aprovado

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