C#根据IP地址查询所属地区（调用免费的IP查询接口）

ip-api.com接口（解析 json需要引入Newtonsoft.Json.dll ）：

/// 
  
        /// 根据IP 获取物理地址  
        /// 
  
        /// Ip地址  
        ///   
        public static string GetIpAddress(string ip)
        {
            string url = "http://ip-api.com/json/"+ip+"?lang=zh-CN";
            string result = "";
            WebRequest wrt = null;
            WebResponse wrp = null;
            try
            {
                wrt = WebRequest.Create(url);
                wrt.Credentials = CredentialCache.DefaultCredentials;

                wrp = wrt.GetResponse();
                StreamReader sr = new StreamReader(wrp.GetResponseStream(), Encoding.UTF8);
                //获取到的是Json数据
                string html = sr.ReadToEnd();

                //Newtonsoft.Json读取数据
                JObject obj = JsonConvert.DeserializeObject(html);
                string city = obj["city"].ToString();
                string province = obj["regionName"].ToString();
                result = city.Equals(province) ? city : (province + city);
            }
            catch (Exception)
            {
            }
            finally
            {
                if (wrp != null)
                    wrp.Close();
                if (wrt != null)
                    wrt.Abort();
            }
            return result;
        }

126.net接口： 

/// 
  
        /// 根据IP 获取物理地址  
        /// 
  
        /// Ip地址  
        ///   
        public static string GetstringIpAddress(string ip)
        {
            string url = "http://ip.ws.126.net/ipquery?ip="+ip;
            string result="";
            WebRequest wrt = null;
            WebResponse wrp = null;
            try
            {
                wrt = WebRequest.Create(url);
                wrt.Credentials = CredentialCache.DefaultCredentials;

                wrp = wrt.GetResponse();
                StreamReader sr = new StreamReader(wrp.GetResponseStream(), Encoding.Default);
                //获取到的数据格式：var lo="江苏省", lc="镇江市"; var localAddress={city:"镇江市", province:"江苏省"}
                string html = sr.ReadToEnd();
                string pattern = "{city:\"(?.*?)\", province:\"(?.*?)\"}";
                Regex regex = new Regex(pattern, RegexOptions.None);
                Match match = regex.Match(html);
                string city=match.Groups["key1"].Value;
                string province=match.Groups["key2"].Value;
               result = city.Equals(province) ? city : (province + city);
            }
            catch (Exception)
            {
            }
            finally
            {
                if (wrp != null)
                    wrp.Close();
                if (wrt != null)
                    wrt.Abort();
            }
            return result;
        }