private void postTweet()
        {
            IsolatedStorageSettings mysetting = IsolatedStorageSettings.ApplicationSettings;
            try
            {
                mysetting.TryGetValue("twitter_token", out value);
                mysetting.TryGetValue("twitter_tokensecret", out value2);
            }
            catch
            {
            }
            if (value == null)
            {
                NavigationService.Navigate(new Uri("/TwitterAuthPage.xaml", UriKind.Relative));
            }
            else
            {
                service = new TwitterService("consumerkey", "consumersecret", value, value2);

                service.SendTweet(new SendTweetOptions { Status = "Testing..." },
                    (statuses, response) =>
                    {
                        if (response.StatusCode == HttpStatusCode.OK)
                        {
                            dispatcher.BeginInvoke(() =>
                            {
                                MessageBox.Show("Tweet sent!");
                            }
                            );
                        }
                        else
                        {
                            throw new Exception(response.StatusCode.ToString());
                        }
                    });
            }
        }