private async void BtnCheckLink_Click(object sender, RoutedEventArgs e)
        {
            string sServer = "";
            string sClient = "";

            sServer = config.FormatIliasUrlToWebServiceLink(txtLoginLink.Text, ref sClient);
            if (sServer != "")
            {
                txtClientId.Text = sClient;

                iconCheck.Visibility    = Visibility.Visible;
                iconFail.Visibility     = Visibility.Hidden;
                iconQuestion.Visibility = Visibility.Hidden;

                config.SetServer(sServer);
                config.SetServerLoginLink(txtLoginLink.Text);
                config.SetClient(sClient);
                config.SetIliasReference(sServer);
            }
            else
            {
                iconCheck.Visibility    = Visibility.Hidden;
                iconQuestion.Visibility = Visibility.Hidden;
                iconFail.Visibility     = Visibility.Visible;

                txtClientId.Text = "";

                var metroWindow = (Application.Current.MainWindow as MetroWindow);
                var result      = await metroWindow.ShowMessageAsync("Error", "Link could not be resolved. Is the correct link specified?", MessageDialogStyle.Affirmative);
            }
        }