1

我有类来创建用户并返回用户信息（成功）。

    class POST
{
    public HttpWebRequest objRequest = null;
    //public static string myRequestData = string.Empty;
    public String myRequestData = String.Empty;
    public String urlAddress = "http://hackathon.kimhieu.info/flashcard/index.php/api/user";
    public  String responseString {get;set;}

    public void doSend()
    {
        StringBuilder completeUrl = new StringBuilder(urlAddress);
        objRequest = (HttpWebRequest)WebRequest.Create(urlAddress.ToString());
        objRequest.ContentType ="application/x-www-form-urlencoded";
        objRequest.Method = "POST";
        //Adding headers
        //objRequest.Headers["Header"]= "Your Value";
        //objRequest.Headers["Content-Language"] = "en-US";

        myRequestData = "username=abcdef&password=abcdef";

    //Begins the asynchronous request
    objRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback),objRequest);


    }
    private  void GetRequestStreamCallback(IAsyncResult asyncResult)
      {
                HttpWebRequest objHttpWebRequest = (HttpWebRequest)asyncResult.AsyncState;
                // End the operation
                Stream postStream = objHttpWebRequest.EndGetRequestStream(asyncResult);
                // Convert the string into a byte array.
                byte[] byteArray = Encoding.UTF8.GetBytes(myRequestData);
                // Write to the request stream.
                postStream.Write(byteArray, 0, myRequestData.Length);
                postStream.Close();

                // Start the asynchronous operation to get the response
                objHttpWebRequest.BeginGetResponse(new AsyncCallback(GetResponseCallback), objHttpWebRequest);
       }

    private void GetResponseCallback(IAsyncResult asyncResult)
            {
                HttpWebRequest objHttpWebRequest = (HttpWebRequest)asyncResult.AsyncState;
                HttpWebResponse objHttpWebResponse = (HttpWebResponse)objHttpWebRequest.EndGetResponse(asyncResult);
                Stream objStreamResponse = objHttpWebResponse .GetResponseStream();
                StreamReader objStreamReader = new StreamReader(objStreamResponse );
                responseString = objStreamReader.ReadToEnd();            // Got response here
                myRequestData = "AAA";
                //MessageBox.Show("RESPONSE :" + responseString);
                // Close the stream object
                objStreamResponse .Close();
                objStreamReader.Close();
                objHttpWebResponse.Close();
       }


}

我调用 Main.xaml.cs

POST ab = new POST();
ab.doSend();                
MessageBox.Show(ab.responseString);

但它返回空字符串我试图在 POST myData 类中分配一些字符串，但它没有执行。我认为 GetResponseCallback(IAsyncResult asyncResult) 不正确。我该如何解决。感谢提前！

4

1 回答 1

2

您编写异步代码，但尝试同步读取responseString。只需将新事件添加到您的 Post 类：

public event Action Completed;

并从方法GetResponseCallback的末尾运行它：

if(Completed != null)
   Completed();

并以这种方式重写您的代码：

POST ab = new POST();
ab.Completed += () => { MessageBox.Show(ab.responseString); };
ab.doSend();

它应该工作

于 2012-05-05T10:26:24.907 回答