IP地址段遍歷

#region 搜索ftp服務器地址

        /// <summary>

        /// 搜索ftp服務器

        /// </summary>

        public void SearchFtpServer()

        {

var beginIp=""192.168.1.1;

var endIp=""192.168.1.251;

            var currentIp = IPAddress.Parse(beginIp);

            var endIp = IPAddress.Parse(endIp);

            var beginNum = GetIpNumber(currentIp);

            var endNum = GetIpNumber(endIp);

            for (long i = beginNum; i <= endNum; i++)

            {

              //TODO:根據ip地址做事

                currentIp = NextIP(currentIp);

            }

        }

        #region ip地址相關

        /// <summary>

        /// 將ip地址轉換為數字表示

        /// </summary>

        /// <param name="ip"></param>

        /// <returns></returns>

        private long GetIpNumber(IPAddress ip)

        {

            var ipBytes = ip.ToString().Split(new char[] { '.' });

            var num = Convert.ToInt64(ipBytes[0]) * 256 * 256 * 256 +

                Convert.ToInt64(ipBytes[1]) * 256 * 256 +

                Convert.ToInt64(ipBytes[2]) * 256 +

                Convert.ToInt64(ipBytes[3]);

            return num;

        }

        /// <summary>

        /// 從一個IPAddress 獲取它的下一個 IPAddress

        /// </summary>

        /// <param name="theIP"></param>

        /// <returns></returns>

        private IPAddress NextIP(IPAddress theIP)

        {

            byte[] ipBytes = theIP.GetAddressBytes();

            if (ipBytes[3] != 255)

            {

                ipBytes[3] += 1;

            }

            else if (ipBytes[2] != 255)

            {

                ipBytes[2] += 1;

                ipBytes[3] = 1;

            }

            else if (ipBytes[1] != 255)

            {

                ipBytes[1] += 1;

                ipBytes[2] = 1;

                ipBytes[3] = 1;

            }

            else if (ipBytes[0] != 255)

            {

                ipBytes[0] += 1;

                ipBytes[1] = 1;

                ipBytes[2] = 1;

                ipBytes[3] = 1;

            }

            IPAddress ip = new IPAddress(ipBytes);

            return ip;

        }

        #endregion