Kladr api

        public String getFias(String parametrs) {
            String[] param = parametrs.Split(',');
            String url = "http://kladr-api.ru/api.php?regionId=30&limit=5";
            foreach (String p in param) {
                url += "&" + p;
            }
            var json = new System.Net.WebClient().DownloadString(url);
            return json;
        }

        public String getFiasCity(String city) {
            return getFias("contentType=city,query="+city);
        }

        public String getFiasStreet(String city, String street)
        {
            return getFias("contentType=street,cityId="+city+"&query=" + street);
        }

        public String getFiasBuilding(String street, String building)
        {
            return getFias("contentType=building,streetId=" + street + ",query=" + building);
        }