private async static void OnSaveXamlCommand(object sender, RoutedEventArgs e) { var fileName = DialogUtil.ShowSaveFileDialog("MyXaml.xaml", "XAML|*.xaml"); if (string.IsNullOrEmpty(fileName)) { return; } var ctrl = sender as LiveXaml; using (var fs = new FileStream(fileName, FileMode.Create, FileAccess.Write, FileShare.Read)) { using (var sw = new StreamWriter(fs, Encoding.UTF8)) { await sw.WriteAsync(ctrl.Text); } } }