Ich möchte wissen, welcher Ansatz unter den beiden eine bessere Umsetzung ist? Ich muss eine Webanforderung erstellen, die zwischen 200 ms und 5 Sekunden liegen kann. Ich brauche die HTML-Antwort, um fortzufahren - also muss ich den Haupt-Thread blockieren.

Erste Ansat

string GetResponse()
{

    HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
    IAsyncResult result = request.BeginGetResponse(null, null);    

using (HttpWebResponse httpResponse = (HttpWebResponse)request.EndGetResponse(result))
{
    using (Stream dataStream = httpResponse.GetResponseStream())
    {
        StreamReader reader = new StreamReader(dataStream);
        response = reader.ReadToEnd();
    }
}

Zweiter Ansatz

string response = string.Empty;
AutoResetEvent waitHandle = null;
void GetResponse(string url)
{
    waitHandle = new AutoResetEvent(false);
    try
    {
        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
        IAsyncResult asyncResult = request.BeginGetResponse(Callback, request);

        waitHandle.WaitOne();
    }
    catch { }
    finally
    {
        waitHandle.Close();
    }
}

    void Callback(IAsyncResult asyncResult)      
    {           

HttpWebRequest request = (HttpWebRequest)asyncResult.AsyncState;
            try
            {
                using (HttpWebResponse httpResponse = (HttpWebResponse)request.EndGetResponse(asyncResult))
                {
                    if (httpResponse.StatusCode == HttpStatusCode.OK)
                    {
                        using (Stream dataStream = httpResponse.GetResponseStream())
                        {
                            StreamReader reader = new StreamReader(dataStream);
                            response = reader.ReadToEnd();
                        }
                    }
                }
            }
            catch { }
            finally
            {
                waitHandle.Set();
            }
        }