c# 请求api获得json数据

    public class HttpUitls
    {
        public static string Get(string Url)
        {
            //System.GC.Collect();
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);
            request.Proxy = null;
            request.KeepAlive = false;
            request.Method = "GET";
            request.ContentType = "application/json; charset=UTF-8";
            request.AutomaticDecompression = DecompressionMethods.GZip;

            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream myResponseStream = response.GetResponseStream();
            StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.UTF8);
            string retString = myStreamReader.ReadToEnd();

            myStreamReader.Close();
            myResponseStream.Close();

            if (response != null)
            {
                response.Close();
            }
            if (request != null)
            {
                request.Abort();
            }

            return retString;
        }

        public static string Post(string Url, string Data, string Referer)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);
            request.Method = "POST";
            request.Referer = Referer;
            byte[] bytes = Encoding.UTF8.GetBytes(Data);
            request.ContentType = "application/x-www-form-urlencoded";
            request.ContentLength = bytes.Length;
            Stream myResponseStream = request.GetRequestStream();
            myResponseStream.Write(bytes, , bytes.Length);

            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            StreamReader myStreamReader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
            string retString = myStreamReader.ReadToEnd();

            myStreamReader.Close();
            myResponseStream.Close();

            if (response != null)
            {
                response.Close();
            }
            if (request != null)
            {
                request.Abort();
            }
            return retString;
        }
    }

string json = HttpUitls.Post("http://music.163.com/api/search/pc", string.Format("s={0}&offset={1}&limit={2}&type={3}", key, "", "", ""), "http://music.163.com/");