C Gaode map obtains the address according to longitude and latitude

using System;
using System.IO;
using System.Net;
using System.Text;

namespace PhotoHelper
{
    public class AmapUtil
    {
        private const string Key = "3ee6df6847015dec899aa46032226fa0";

        /// <summary>
        ///      Get the address according to latitude and longitude 
        /// </summary>
        /// <param name="lngLatStr"> String of longitude and latitude   for example :"113.692100,34.752853"</param>
        /// <param name="timeout"> Timeout defaults to 10 second </param>
        /// <returns> Failure to return "" </returns>
        public static string GetLocationByLngLat(string lngLatStr, int timeout = 10000)
        {
            var url = $"http://restapi.amap.com/v3/geocode/regeo?key={Key}&location={lngLatStr}";
            return GetLocationByUrl(url, timeout);
        }

        /// <summary>
        ///      Get the address according to latitude and longitude 
        /// </summary>
        /// <param name="lng"> longitude   for example :113.692100</param>
        /// <param name="lat"> dimension   for example :34.752853</param>
        /// <param name="timeout"> Timeout defaults to 10 second </param>
        /// <returns> Failure to return "" </returns>
        public static string GetLocationByLngLat(double lng, double lat, int timeout = 10000)
        {
            var url = $"http://restapi.amap.com/v3/geocode/regeo?key={Key}&location={lng},{lat}";
            return GetLocationByUrl(url, timeout);
        }

        /// <summary>
        ///      according to URL Get address 
        /// </summary>
        /// <param name="url">Get Methodical URL</param>
        /// <param name="timeout"> Timeout defaults to 10 second </param>
        /// <returns></returns>
        private static string GetLocationByUrl(string url, int timeout = 10000)
        {
            var s = "";
            try
            {
                if (WebRequest.Create(url) is HttpWebRequest req)
                {
                    req.ContentType = "multipart/form-data";
                    req.Accept = "*/*"; 
                    req.UserAgent = "";
                    req.Timeout = timeout;
                    req.Method = "GET";
                    req.KeepAlive = true;
                    if (req.GetResponse() is HttpWebResponse response)
                        using (var sr = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
                        {
                            s = sr.ReadToEnd();
                            return s;
                        }
                }
            }
            catch (Exception ex)
            {
                s = ex.ToString();
            }

            return s;
        }
    }
}

Be careful ： In this paper, the Key It's a personal application I applied for , There are times and frequency limits , Please replace the formal environment with your own Key.