public static string ConvertISBNToEAN(this string TargetISBN, string EANPrefix = "978")
{
int nCheckSum;
int nTemp;
string EAN;
string ISBN;
// Initialization
nTemp = 0;
nCheckSum = 0;
EAN = "";
if (TargetISBN.Length < CONST_ISBN_LEN)
{
ISBN = TargetISBN.PadLeft(CONST_ISBN_LEN, '0');
}
else
{
ISBN = TargetISBN;
}
if (!ISBN.IsISBNValid())
{
return("");
}
if (EANPrefix.Length != 3)
{
return("");
}
EAN = EANPrefix + ISBN.Substring(0, (CONST_ISBN_LEN - 1));
nCheckSum = 0;
for (uint i = 0; i < EAN.Length; i++)
{
char cTempVal = EAN.ToCharArray()[i];
// Do not convert the number directly from a char, since we do not want the ASCII value
// nTemp = Convert.ToInt32(cTempVal);
nTemp = Convert.ToInt32(new String(new char[] { cTempVal }));
if (nTemp > 0)
{
if ((i % 2) == 0)
{
nCheckSum += nTemp;
}
else
{
nCheckSum += (3 * nTemp);
}
}
}
nCheckSum = (CONST_ISBN_LEN - (nCheckSum % 10)) % 10;
EAN += Convert.ToString(nCheckSum);
return(EAN);
}
