/// <summary>Determines whether the specified value of the object is valid.</summary>
/// <param name="value">The value of the object to validate.</param>
/// <returns><see langword="true"/> if the specified value is valid; otherwise, <see langword="false"/>.</returns>
public override bool IsValid(object value)
{
string valueToValidate = value as string;
if (string.IsNullOrWhiteSpace(valueToValidate))
{
/* This may seem strange, but in order to reject empty values the RequiredAttribute should be used */
return(true);
}
/* Then, check if the account number matches the regular expression */
Match match = new IbanValidatorRegex().Match(valueToValidate);
if (!match.Success)
{
return(false);
}
/* If the account number passes the regex check, continue to check the contents */
string countryCode = match.Groups["countrycode"].Value;
int checkDigits = int.Parse(match.Groups["check_digits"].Value, CultureInfo.InvariantCulture);
string accountId = match.Groups["accountid"].Value;
BigInteger working = ConvertToNumeric(accountId + countryCode + checkDigits);
BigInteger remainder = working % 97;
bool isValid = remainder == 1;
return(isValid);
}
/// <summary>Implements the validation logic for the receiver.</summary>
/// <param name="objectToValidate">The object to validate.</param>
/// <param name="currentTarget">The object on the behalf of which the validation is performed.</param>
/// <param name="key">The key that identifies the source of objectToValidate.</param>
/// <param name="validationResults">The validation results to which the outcome of the validation should be stored.</param>
protected override void DoValidate(string objectToValidate, object currentTarget, string key, ValidationResults validationResults)
{
/* First, check if the account number has a value. */
if (string.IsNullOrEmpty(objectToValidate))
{
if (this.Negated)
{
this.LogValidationResult(validationResults, this.GetMessage(objectToValidate, key), currentTarget, key);
}
return;
}
/* Then, check if the account number matches the regular expression */
Match match = new IbanValidatorRegex().Match(objectToValidate);
if (!match.Success && !this.Negated)
{
this.LogValidationResult(validationResults, this.GetMessage(objectToValidate, key), currentTarget, key);
return;
}
else if (!match.Success && this.Negated)
{
return;
}
/* If the account number passes the regex check, continue to check the contents */
string countryCode = match.Groups["countrycode"].Value;
int checkDigits = int.Parse(match.Groups["check_digits"].Value, CultureInfo.InvariantCulture);
string accountId = match.Groups["accountid"].Value;
BigInteger working = ConvertToNumeric(accountId + countryCode + checkDigits);
BigInteger remainder = working % 97;
bool isValid = remainder == 1;
isValid = this.Negated ? !isValid : isValid;
if (!isValid)
{
this.LogValidationResult(validationResults, this.GetMessage(objectToValidate, key), currentTarget, key);
}
}
