C# 后台模拟前台post发送json数据

 public static string PostMoths(string url, string param)
    {
        string strURL = url;
        System.Net.HttpWebRequest request;
        request = (System.Net.HttpWebRequest)WebRequest.Create(strURL);
        request.Method = "POST";
        request.ContentType = "application/json;charset=UTF-8";
        string paraUrlCoded = param;
        byte[] payload;
        payload = System.Text.Encoding.UTF8.GetBytes(paraUrlCoded);
        request.ContentLength = payload.Length;
        Stream writer = request.GetRequestStream();
        writer.Write(payload, 0, payload.Length);
        writer.Close();
        System.Net.HttpWebResponse response;
        response = (System.Net.HttpWebResponse)request.GetResponse();
        System.IO.Stream s;
        s = response.GetResponseStream();
        string StrDate = "";
        string strValue = "";
        StreamReader Reader = new StreamReader(s, Encoding.UTF8);
        while ((StrDate = Reader.ReadLine()) != null)
        {
            strValue += StrDate + "\r\n";
        }
        return strValue;
    }