private async void _settingVM_Deactivated(object sender, DeactivationEventArgs e) { _settingVM.Deactivated -= _settingVM_Deactivated; bool ok = _settingVM.DialogResult; if (ok) { var config = await JsonHelper.JsonDeserializeFromFileAsync <SettingObject>(AppManager.SettingPath); await AppManager.ApplySetting(config); await _eventAggregator.PublishOnUIThreadAsync(new SettingSaved()); } _settingVM = null; }