AsyncHttpWebRequest(网页标题检索程序)

我试图创建一个程序，将检索页面标题给定的url。我写的代码，当我不使用AsyncCallback工作，但当我使用AsyncCallback代码似乎不工作。

public void GetWebPageTitle(string URL)
{
    // make request for web page
    HttpWebRequest myWebRequest = (HttpWebRequest)HttpWebRequest.Create(URL);
    myWebRequest.Method = "GET";
    myWebRequest.BeginGetResponse(new AsyncCallback(FinishWebRequest), myWebRequest);
    zConsole.WriteLine("Beginning HttpWebRequest for: " + URL);
}
void FinishWebRequest(IAsyncResult result)
{
    zConsole.WriteLine("...");
    string title = "Unknown";
    //Code under here doesnt get extcuted
    HttpWebResponse myWebResponse = (HttpWebResponse)((HttpWebRequest)result.AsyncState).EndGetResponse(result);
    StreamReader myWebSource = new StreamReader(myWebResponse.GetResponseStream());
    string source = "";            
    source = myWebSource.ReadToEnd();
    myWebResponse.Close();
    title = Regex.Match(source, @"'<title'b[^>]*'>'s*(?<Title>['s'S]*?)'</title'>", RegexOptions.IgnoreCase).Groups["Title"].Value;
    zConsole.WriteLine(title);
}

谢谢。