Fetching Result from HTTP Response

Question

I have the following C# class which initiates an HTTP request from a Windows Phone to a server:

public class Request
{
    public string data;
    public string result;

    public Request()
    {

    }

    public void doRequest(string parameters, string URL)
    {
        data = parameters;

        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(URL);
        request.Method = "POST";
        request.ContentType = "application/x-www-form-urlencoded";
        request.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), request);
    }

    public void GetRequestStreamCallback(IAsyncResult callbackResult)
    {
        HttpWebRequest myRequest = (HttpWebRequest)callbackResult.AsyncState;
        Stream postStream = myRequest.EndGetRequestStream(callbackResult);
        byte[] byteArray = Encoding.UTF8.GetBytes(data);

        postStream.Write(byteArray, 0, byteArray.Length);
        postStream.Close();

        myRequest.BeginGetResponse(new AsyncCallback(GetResponsetStreamCallback), myRequest);
    }

    public void GetResponsetStreamCallback(IAsyncResult callbackResult)
    {
        HttpWebRequest request = (HttpWebRequest)callbackResult.AsyncState;
        HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(callbackResult);

        StreamReader httpWebStreamReader = new StreamReader(response.GetResponseStream());
        result = httpWebStreamReader.ReadToEnd();
    }

Now, in my main class, I call the doRequest method to do an HTTP request from the Windows Phone:

Request req = new Request();
req.doRequest("function=LogIn&username=" + username + "&password=" + password, "http://localhost:4000/Handler.ashx");

When calling this method, how can I get the result (the result variable) from the server since it is received in the GetResponsetStreamCallback method and not in the doRequest method?

Answer 1

You have several possibilities. One would be to define property to make the result accessible outside. Define

public class Request
{
    public string Result
    {
      get{ 
           if(result != null && !string.IsNullOrEmpty(result))
                return result;
           return null;
         }
    }
  ...
}

You might create an event and have objects subscribe to it, so you can notice them when the asynchronous request has ended. Or make your calls synchronous, which is a little easier to do, as you don't have synchronize your calls and the requests from other objects.