public SettingsViewModel() { // 由于默认值不是常量,因此需要动态注册 SettingService.Instance.RegisterSetting(this, nameof(PriorSource), null, MediaSources.First()); SettingService.Instance.RegisterSetting(this, nameof(Theme), null, ThemeList.First()); SettingService.Instance.RegisterSetting(this, nameof(ReminderSpanAhead), null, TimeSpan.FromMinutes(5)); SettingService.Instance.ApplySettingAttributes(this); ClearCacheFiles = new DelegateCommand(async() => { await CacheService.ClearCache(); await new MessageDialog("成功清空缓存", "成功").ShowAsync(); CacheFileSize = 0; }, () => CacheFileSize > 0); }