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;
}