判断某个IPv4地址是否在指定CIDR格式IPv4地址段中（代码）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace WindowsFormsApp1
{
    public class Ipv4
    {
        #region IPv4 List
        /// <summary>
        /// 这里填写 CIDR格式IP地址段 
        /// https://github.com/LisonFan/china_ip_list/blob/master/china_ipv4_list
        /// https://www.ipaddressguide.com/cidr
        /// </summary>
        static string ipv4List = @""; 
        #endregion
        public static bool CheckIpInList(string ip)
        {
            string[] ipAndMask = ipv4List.Split(new char[] { '\n' });
            List<IPv4Data> ips = new List<IPv4Data>();
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < ipAndMask.Length; i++)
            {
                string[] iNm = ipAndMask[i].Split(new char[] { '/' });
                if (iNm.Length == 2)
                {
                    IPv4Data ipData = new IPv4Data();
                    string ipStr = iNm[0];
                    int mask = int.Parse(iNm[1]);
                    ipData.IP = IpToUint(ipStr);
                    ipData.ShortIp = ipData.IP >> (32 - mask);
                    uint maskUint = uint.MaxValue << (32 - mask);
                    ipData.MaxIp = ipData.IP | ~maskUint;
                    ipData.IpBit = Convert.ToString(ipData.IP, 2);
                    ipData.ShortIpBit = Convert.ToString(ipData.ShortIp, 2);
                    ipData.MaxIpBit = Convert.ToString(ipData.MaxIp, 2);
                    ipData.IpBlock = ipAndMask[i];
                    sb.AppendLine(ipStr);
                    sb.AppendLine(ipData.ShortIpBit);
                    sb.AppendLine(ipData.IpBit);
                    sb.AppendLine(ipData.MaxIpBit);
                    sb.AppendLine();
                    ips.Add(ipData);
                }
            }
            uint checkIp = IpToUint(ip);
            for (int i = 0; i < ips.Count; i++)
            {
                IPv4Data ipData = ips[i];
                if (checkIp > ipData.IP && checkIp < ipData.MaxIp)
                {
                    return true;
                }
            }
            string show = sb.ToString();
            return false;
        }
        public static uint IpToUint(string ip)
        {
            string[] ipByte = ip.Split(new char[] { '.' });
            uint ip1 = uint.Parse(ipByte[0]) << 24;
            uint ip2 = uint.Parse(ipByte[1]) << 16;
            uint ip3 = uint.Parse(ipByte[2]) << 8;
            uint ip4 = uint.Parse(ipByte[3]);
            return ip1 | ip2 | ip3 | ip4;
        }
    }


    public class IPv4Data
    {
        public string IpBlock { get; set; }
        public string MaxIpBit { get; set; }
        public string IpBit { get; set; }
        public string ShortIpBit { get; set; }//右移掩码的补数位
        public uint ShortIp { get; set; }//右移掩码的补数位
        public uint IP { get; set; }
        public uint MaxIp { get; set; }
    }
}