Question

I’m running into a bit of problem when trying to readToEnd from an asynchronous webrequest. Here’s the code:

    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.
    }

When trying to invoke the readToEnd method, I get this error message: The stream does not support concurrent I/O read or write operations.

I’ve searched, but I could not find a solution to this problem. How can it be fixed?

Answer 1

That’s because you’re trying to do two reads. The call to BeginRead initiates a read operation. Then ReadToEnd initiates another read operation on the same stream.

I think what you want is just the ReadToEnd. Remove the call to ResponseStream.BeginRead.