c# 调用 友盟api

public static void post5()
        {
            string url = "http://msg.umeng.com/api/send";
            HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
            request.Method = "POST";
            string str = "{\"appKey\":\"***\",\"timestamp\":1415872474403,\"validation_token\":\"***\",\"type\":\"broadcast\",\"payload\":{\"aps\":{ \"alert\":\"xxx\"}},\"policy\":{},\"production_mode\":\"false\",\"description\":\"xxx\"}";
            
            byte[] bs = Encoding.ASCII.GetBytes(str);
            request.ContentLength = bs.Length;
            using (Stream reqStream = request.GetRequestStream())
            {
                reqStream.Write(bs, 0, bs.Length);
                reqStream.Close();
            }
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            HttpStatusCode statusCode = response.StatusCode;
        }