IP段转换为 list

public static List<String> StringToIPList(string strIPs)
        {
            var reg1 = new Regex(@"(((2[0-4]d)|(25[0-5])|([0-1]?d{1,2})).?){4}(-(((2[0-4]d)|(25[0-5])|([0-1]?d{1,2})).?){4})");
            var reg2 = new Regex(@"^(((2[0-4]d)|(25[0-5])|([0-1]?d{1,2})).?){4}$");
            if (string.IsNullOrEmpty(strIPs))
            {
                return new List<string>();
            }
            var ips = strIPs.Split(',');
            var ipList = new List<string>();
            var tempList = new List<string>();
            object a = null;
            foreach (var item in ips)
            {
                if (reg1.IsMatch(item))
                {
                    tempList.Add(item);
                }
                if (reg2.IsMatch(item))
                {
                    a = reg2.Matches(item);
                    ipList.Add(item);
                }
            }
            var ipListList = new List<String>();
            foreach (var item in tempList)
            {
                var tempIps = item.Split('-');
                var tempResult = true;
                foreach (var regItem in tempIps)
                {
                    tempResult &= reg2.IsMatch(regItem);
                }
                if (!tempResult) continue;
                var list = new List<List<int>>();
                foreach (var loopItem in tempIps)
                {
                    var nums = loopItem.Split('.');
                    if (nums.Length != 4) continue;
                    var listPart = new List<int>();
                    foreach (var num in nums)
                    {
                        listPart.Add(int.Parse(num));
                    }
                    list.Add(listPart);
                }
                if (list.Count > 2) continue;
                var listRealPartIps = new List<String>();
                for (int i = 0; i < 4; i++)
                {
                    var tempPartList = new List<String>();
                    if (list[0][i] > list[1][i]) continue;
                    if (list[0][i] == list[1][i])
                    {
                        if (i == 0)
                        {
                            tempPartList.Add(list[0][i].ToString());
                        }
                        else
                        {
                            foreach (var leftNums in listRealPartIps)
                            {
                                tempPartList.Add(leftNums + "." + (list[0][i]).ToString());
                            }
                        }
                    }
                    else
                    {
                        var ipCount = list[1][i] - list[0][i] + 1;
                        for (int k = 0; k < ipCount; k++)
                        {
                            if (i == 0)
                            {
                                tempPartList.Add((list[0][i] + k).ToString());
                            }
                            else
                            {
                                foreach (var leftNums in listRealPartIps)
                                {
                                    tempPartList.Add(leftNums + "." + (list[0][i] + k).ToString());
                                }
                            }
                        }
                    }
                    listRealPartIps = tempPartList;
                }
                ipList.AddRange(listRealPartIps);
            }
            return ipList;
        }