C#判断一个给定的IP地址是否在指定的范围内

public static long IP2Long(string ip)
   {
       string[] ipBytes;
       double num = 0;
       if(!string.IsNullOrEmpty(ip))
       {
           ipBytes = ip.Split('.');
           for (int i = ipBytes.Length - 1; i >= 0; i--)
           {
               num += ((int.Parse(ipBytes[i]) % 256) * Math.Pow(256, (3 - i)));
           }
       }
       return (long)num;
   }

long start = IP2Long("127.0.0.1");
long end = IP2Long("127.0.0.255");
long ipAddress = IP2Long("127.0.1.253");
bool inRange = (ipAddress >= start && ipAddress <= end);
if (inRange){
  //IP Address fits within range!
}</pre>