Http 异步请求无响应

Question

我使用HttpWebRequest访问Http请求，使用异步方法时无响应

public async Task<string> PostAsync(string url, string postData, Hashtable headht = null)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "POST";
            request.ContentType = "application/json;charset=UTF-8";
            request.Accept = "application/json";
            request.Timeout = 10000;

            #region headers设置
            if (headht != null)
            {
                foreach (DictionaryEntry item in headht)
                {
                    request.Headers.Add(item.Key.ToString(), item.Value.ToString());
                }
            }
            #endregion

            byte[] paramJsonBytes;
            paramJsonBytes = System.Text.Encoding.UTF8.GetBytes(postData);
            request.ContentLength = paramJsonBytes.Length;

            using (Stream reqStream = request.GetRequestStream())
            {
                reqStream.Write(paramJsonBytes, 0, paramJsonBytes.Length);
                reqStream.Close();
            }

            var response = request.GetResponseAsync() as HttpWebResponse;

            Stream resStream = response.GetResponseStream();
            StreamReader reader = new StreamReader(resStream);
            string text = reader.ReadToEnd();
            return text;
        }

但是我将异步改成同步就没有这个问题

var response = request.GetResponse() as HttpWebResponse;
这需要怎么解决

Answer 1

异步方式的返回，不是通过这种方式获取。因为是异步，结果不会马上给你，给你的只是一个响应，告诉你调用成功了。至于收到结果的时间，取决于这个异步方法后端的执行时间，真实结果的获取方式也取决于所异步的具体实现，查看相关的手册。