判断一个IP是否在指定IP范围内

public class IPRegion
    {
        public static bool IPInRegion(string beginIP, string endIP, string inputIP)
        {
            IPAddress _beginip;
            IPAddress _endip;
            IPAddress _inputip;
            try
            {
                _beginip = IPAddress.Parse(beginIP);
                _endip = IPAddress.Parse(endIP);
                _inputip = IPAddress.Parse(inputIP);
            }
            catch (Exception ex)
            {
                ErrorHandler.Handle(ex);
                return false;
            }
            if (_beginip == null || _endip == null || _inputip == null) return false;

            byte[] _beginbyte = _beginip.GetAddressBytes();
            Int64 _beginint = ConvertIPToInt(_beginbyte);
            byte[] _endbyte = _endip.GetAddressBytes();
            Int64 _endint = ConvertIPToInt(_endbyte);

            if (_beginint > _endint) return false;

            byte[] _inputtype = _inputip.GetAddressBytes();
            Int64 _inputint = ConvertIPToInt(_inputtype);

            return (_inputint <= _endint && _inputint >= _beginint);
        }

        protected static Int64 ConvertIPToInt(byte[] _bytes)
        {
            if (_bytes.Length != 4) return 0;
            string _intstring = "";
            for (int i = 0; i < _bytes.Length; i++)
            {
                _intstring += FormatIPPart(_bytes[i].ToString());
            }
            Int64 _outputint;
            return !Int64.TryParse(_intstring, out _outputint) ? 0 : _outputint;
        }

        protected static string FormatIPPart(string _ippart)
        {
            Regex _regx = new Regex(@"^\d{1,3}$");
            if (!_regx.IsMatch(_ippart)) return "000";
            while (_ippart.Length < 3)
            {
                _ippart = "0" + _ippart;
            }
            return _ippart;
        }
    }