public static class BaiduConstParams
    {
        public const string PlaceApIv2Search = "http://api.map.baidu.com/place/v2/search";
        public const string PlaceApIv2Detail = "http://api.map.baidu.com/place/v2/detail";
        public const string PlaceApIv2Eventsearch = "http://api.map.baidu.com/place/v2/eventsearch";
        public const string PlaceApIv2Eventdetail = "http://api.map.baidu.com/place/v2/eventdetail";
        public const string GeocodingApIv2 = "http://api.map.baidu.com/geocoder/v2/";
        public const string GeocodingApIv2Reverse = "http://api.map.baidu.com/geocoder/v2/";
        public const string TranslateApi = "http://openapi.baidu.com/public/2.0/bmt/translate";
        public const string GeoconvApi = "http://api.map.baidu.com/geoconv/v1/";
    }

    public static class BaiduErrorMessages
    {
        public const string NotKey = "密鑰不存在";
        public const string LackParam = "缺少必要請求參數";
    }

public enum BaiduLbsType
    {
        PlaceApIv2Search,
        PlaceApIv2Detail,
        PlaceApIv2Eventsearch,
        PlaceApIv2Eventdetail,
        GeocodingApIv2,
        GeocodingApIv2Reverse,
        Translate,
        Geoconv
    }

    public enum Status
    {
        /// <summary>
        /// 正常   
        /// </summary>
        Ok = 0,
        /// <summary>
        /// 請求參數非法   
        /// </summary>
        ParameterInvalid = 2,
        /// <summary>
        /// 權限校驗失敗
        /// </summary>
        VerifyFailure = 3,
        /// <summary>
        /// 配額校驗失敗
        /// </summary>
        QuotaFailure = 4,
        /// <summary>
        /// 不存在或者非法   
        /// </summary>
        AkFailure = 5,
        /// <summary>
        /// Transform 內部錯誤
        /// </summary>
        InternalError = 1,
        /// <summary>
        /// from非法
        /// </summary>
        FromIllegal = 21,
        /// <summary>
        /// to非法
        /// </summary>
        ToIllegal = 22,
        /// <summary>
        /// coords非法
        /// </summary>
        CoordsIllegal = 24,
        /// <summary>
        /// coords個數非法，超過限制
        /// </summary>       
        CoordsCountIllegal = 25

    }

public class BaiduGeocodingResults
    {
        /// <summary>
        /// 返回結果狀態值， 成功返回0，其他值請查看附錄。
        /// </summary>
        [JsonProperty(PropertyName = "status")]
        public Status Status;

        /// <summary>
        /// 返回結果狀態值， 成功返回0，其他值請查看附錄。
        /// </summary>
        [JsonProperty(PropertyName = "result")]
        public BaiduGeocodingResult Result;
    }

    public class BaiduGeocodingResult
    {
        /// <summary>
        /// 經緯度坐標
        /// </summary>
        [JsonProperty(PropertyName = "location")]
        public BaiduGeocodingLoaction Location;
        /// <summary>
        /// 位置的附加信息，是否精確查找。1為精確查找，0為不精確。
        /// </summary>
        [JsonProperty(PropertyName = "precise")]
        public int Precise;
        /// <summary>
        /// 可信度
        /// </summary>
        [JsonProperty(PropertyName = "confidence")]
        public int Confidence;
        /// <summary>
        /// 地址類型
        /// </summary>
        [JsonProperty(PropertyName = "level")]
        public string Level;

        /// <summary>
        /// 結構化地址信息
        /// </summary>
        [JsonProperty(PropertyName = "formatted_address")]
        public string FormattedAddress;

        /// <summary>
        /// 所在商圈信息，如 "人民大學,中關村,蘇州街"
        /// </summary>
        [JsonProperty(PropertyName = "business")]
        public string Business;

        /// <summary>
        /// 具體地址
        /// </summary>
        [JsonProperty(PropertyName = "addressComponent")]
        public BaiduGeocodingAddress AddressComponent;
    }

    public class BaiduGeocodingLoaction
    {
        /// <summary>
        /// 緯度值
        /// </summary>
        [JsonProperty(PropertyName = "lat")]
        public decimal Lat;
        /// <summary>
        /// 經度值
        /// </summary>
        [JsonProperty(PropertyName = "lng")]
        public decimal Lng;
    }

    public class BaiduGeocodingAddress
    {
        /// <summary>
        /// 城市名
        /// </summary>
        [JsonProperty(PropertyName = "city")]
        public string City;
        /// <summary>
        /// 區縣名
        /// </summary>
        [JsonProperty(PropertyName = "district")]
        public string District;
        /// <summary>
        /// 省名
        /// </summary>
        [JsonProperty(PropertyName = "province")]
        public string Province;
        /// <summary>
        /// 街道名
        /// </summary>
        [JsonProperty(PropertyName = "street")]
        public string Street;
        /// <summary>
        /// 街道門牌號
        /// </summary>
        [JsonProperty(PropertyName = "street_number")]
        public string StreetNumber;
    }

public class BaiduLbs
    {
        private readonly string _key;

        public static string CurrentRequest = "";

        public BaiduLbs(string key)
        {
            _key = key;
        }

        /// <summary>
        /// 請求
        /// </summary>
        /// <param name="param"></param>
        /// <param name="baiduLbsType"></param>
        /// <param name="encoding"></param>
        /// <param name="action"></param>
        public void Request(string param, BaiduLbsType baiduLbsType, Encoding encoding, Action<string> action)
        {
            WebClient webClient = new WebClient { Encoding = encoding };
            string url = "";
            switch (baiduLbsType)
            {
                case BaiduLbsType.PlaceApIv2Search:
                    url = string.Format(BaiduConstParams.PlaceApIv2Search + "?{0}", param);
                    break;
                case BaiduLbsType.PlaceApIv2Detail:
                    url = string.Format(BaiduConstParams.PlaceApIv2Detail + "?{0}", param);
                    break;
                case BaiduLbsType.PlaceApIv2Eventsearch:
                    url = string.Format(BaiduConstParams.PlaceApIv2Eventsearch + "?{0}", param);
                    break;
                case BaiduLbsType.PlaceApIv2Eventdetail:
                    url = string.Format(BaiduConstParams.PlaceApIv2Eventdetail + "?{0}", param);
                    break;
                case BaiduLbsType.GeocodingApIv2:
                case BaiduLbsType.GeocodingApIv2Reverse:
                    url = string.Format(BaiduConstParams.GeocodingApIv2 + "?{0}", param);
                    break;
                case BaiduLbsType.Translate:
                    url = string.Format(BaiduConstParams.TranslateApi + "?{0}", param);
                    break;
                case BaiduLbsType.Geoconv:
                    url = string.Format(BaiduConstParams.GeoconvApi + "?{0}", param);
                    break;

            }
            CurrentRequest = url;
            action(webClient.DownloadString(url));
        }

        /// <summary>
        /// 響應
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="param"></param>
        /// <param name="baiduLbsType"></param>
        /// <param name="encoding"></param>
        public T Response<T>(string param, BaiduLbsType baiduLbsType, Encoding encoding)
        {
            T t = default(T);

            Request(param, baiduLbsType, encoding, json =>
                {
                    if (baiduLbsType == BaiduLbsType.GeocodingApIv2 || baiduLbsType == BaiduLbsType.GeocodingApIv2Reverse)
                    {
                        if (json.Contains("/"result/":[]"))
                        {
                            json = json.Replace("/"result/":[]", "/"result/":{}");
                        }
                    }
                    t = (T)JsonConvert.DeserializeObject(json, typeof(T));
                });
            return t;
        }

        public BaiduGeocodingResults BaiduGeocoding(string address, string city)
        {
            address = System.Web.HttpUtility.UrlEncode(address);
            city = System.Web.HttpUtility.UrlEncode(city);
            string request = string.Format("address={0}&output=json&ak={1}&city={2}", address, _key, city);
            var result = Response<BaiduGeocodingResults>(request, BaiduLbsType.GeocodingApIv2, Encoding.UTF8);
            if (result.Status == Status.Ok && result.Result.Location == null)
            {
                request = string.Format("address={0}&output=json&ak={1}&city={2}", city + address, _key, city);
                return Response<BaiduGeocodingResults>(request, BaiduLbsType.GeocodingApIv2, Encoding.UTF8);
            }
            return result;
        }

        public BaiduGeocodingResults BaiduGeocoding(string longitude, string dimensions, string pois)
        {
            var location = longitude + "," + dimensions;
            string request = string.Format("ak={0}&location={1}&pois={2}", _key, location, pois);
            return Response<BaiduGeocodingResults>(request, BaiduLbsType.GeocodingApIv2, Encoding.UTF8);
        }

     
        public GeoconvResults BaiduGeoconv(GeoconvParams geoconvParams, ref List<GeoconvPOI> geoconvPois)
        {
            geoconvParams.Ak = _key;
            return Response<GeoconvResults>(geoconvParams.ToString(ref geoconvPois), BaiduLbsType.Geoconv, Encoding.UTF8);
        }

        public GeoconvResults BaiduGeoconv(GeoconvParams geoconvParams, GeoconvPOI geoconvPoi)
        {
            geoconvParams.Ak = _key;
            List<GeoconvPOI> geoconvPois = new List<GeoconvPOI>
                                               {
                                                   geoconvPoi
                                               };
            return Response<GeoconvResults>(geoconvParams.ToString(ref geoconvPois), BaiduLbsType.Geoconv, Encoding.UTF8);
        }
    }