public static string LongToIP(long longIP)
{
string ip = string.Empty;
for (int i = 0; i < 4; i++)
{
int num = (int)(longIP / Math.Pow(256, (3 - i)));
longIP = longIP - (long)(num * Math.Pow(256, (3 - i)));
if (i == 0)
ip = num.ToString();
else
ip = ip + "." + num.ToString();
}
return ip;
}