c# - 等待 HttpWebRequest.BeginGetRequestStream 结束

Question

我正在尝试使用 HttpWebRequest.BeginGetRequestStream 方法。在我的方法中，我得到了一些 Json。我需要等待这个方法 (HttpWebRequest.BeginGetRequestStream) 结束来分析我的 Json。

这是我的代码:

private string API_Query(string url)
{
    HttpWebRequest requete = (HttpWebRequest)HttpWebRequest.Create(url);
    requete.Method = "POST";
    requete.ContentType = "application/x-www-form-urlencoded";

    requete.BeginGetRequestStream(DebutReponse, requete);//wait the end of this method
    //analyse the json here
    return null;
}

问题是我不知道如何等待方法结束。我尝试了不同的方法，例如任务和线程，但我不确定如何正确执行。

感谢您的帮助。

Answer 1

The problem is that I don't know how to wait the end the method.

有很多方法可以做到这一点。在我看来，您想同步调用请求，我建议只需调用 GetResponseStream:

private string ApiQuery(string url)
{
   HttpWebRequest requete = (HttpWebRequest)HttpWebRequest.Create(url);
   requete.Method = "POST";
   requete.ContentType = "application/x-www-form-urlencoded";

   using (var requestStream = requete.GetRequestStream())
   {
      // Write to request stream
   }

   using (var responseStream = requete.GetResponse())
   {
      // Read the respone stream, parsing out your JSON.
   }
}

编辑:

正如您在评论中提到的，这是一个 Silverlight 项目。这意味着您没有 HttpWebRequest 的同步版本。相反，您可以使用 WebClient:

var webClient = new WebClient()
webClient.OpenReadCompleted += OnUploadCompleted;
webClient.OpenReadAsync(url, data);

private void OnUploadCompleted(object sender, OpenReadCompletedEventArgs e)
{
    if (e.Error != null)
    {
         // Error, do something useful
         return;
    }
    using (var responseStream = e.Result)
    {
           byte[] data = (byte[]) e.UserState;
          // Read response from stream.
    }
}