异步I/O（从异步webrequest读取流）

Question

尝试从异步webrequest进行readToEnd时遇到了一些问题。下面的代码：

public void GetHTTP(string http) 
    { 
     request = (HttpWebRequest)WebRequest.Create(http); 
     RequestState rs = new RequestState(); // Class to hold state. Can ignore... 
     Setup(); // contain statements such as request.Accept =...; 
     rs.Request = request; 
     IAsyncResult r = (IAsyncResult)request.BeginGetResponse(new AsyncCallback ResponseSetup), rs); 
     allDone.WaitOne(); 
     Referer = http; //Can ignore this... 
    } 

    private void ResponseSetup(IAsyncResult ar) 
    { 
     RequestState rs = (RequestState)ar.AsyncState; 
     WebRequest request = rs.Request; 
     WebResponse response = request.EndGetResponse(ar); 
     Stream ResponseStream = response.GetResponseStream(); 
     rs.ResponseStream = ResponseStream; 
     IAsyncResult iarRead = ResponseStream.BeginRead(rs.BufferRead, 0, BUFFER_SIZE, new AsyncCallback(ReadCallBack), rs); 
     StreamReader reader = new StreamReader(ResponseStream); 
     information = reader.ReadToEnd(); 
     //The problem is right here; ReadToEnd. 
    } 

当试图调用ReadToEnd的方法，我得到这个错误信息：该流不支持并发I/O读取或写入操作。

我查过了，但找不到解决这个问题的办法。它如何被修复？

Answer 1

这是因为你试图做两个读取。对BeginRead的调用启动读取操作。然后ReadToEnd在同一个流上启动另一个读取操作。

我想你想要的只是ReadToEnd。取消对ResponseStream.BeginRead的呼叫。