void LoginCallback(IAsyncResult result) { ICloudStorageAccessToken token = m_dropBox.EndOpenRequest(result); if (token != null) { m_dropBox.BeginGetRootRequest(RootCallback); } else if (m_dropBox.IsOpened) { m_dropBox.BeginGetRootRequest(RootCallback); } else { Deployment.Current.Dispatcher.BeginInvoke(() => { LoadingFileList = false; }); } }