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| public bool IsEgnValid(string egn)
{
if (string.IsNullOrEmpty(egn)) return false;
if (egn.Length != 10) { return false; }
double num;
if (!double.TryParse(egn, out num)) { return false; }
int[] weights = { 2, 4, 8, 5, 10, 9, 7, 3, 6 };
string date = string.Empty;
DateTime dt;
int year = Int16.Parse(egn.Substring(0, 2));
int month = Int16.Parse(egn.Substring(2, 2));
int day = Int16.Parse(egn.Substring(4, 2));
if (month > 40)
{
date = (month - 40) + "-" + day + "-" + (year + 2000);
}
else if (month > 20)
{
date = (month - 20) + "-" + day + "-" + (year + 1800);
}
else
{
date = month + "-" + day + "-" + (year + 1900);
}
if (DateTime.TryParse(date, out dt) == false) { return false; }
int checkSum = Int32.Parse(egn.Substring(9, 1));
int egnSum = 0;
int validCheckSum = 0;
for (int i = 0; i < 9; i++)
{
egnSum += int.Parse(egn.Substring(i,1)) * weights[i];
}
validCheckSum = egnSum % 11;
if (validCheckSum == 10) { validCheckSum = 0; }
if (checkSum == validCheckSum) { return true; }
else { return false; }
} |
