public StartPage() { InitializeComponent(); Lessons = JsonConvert.DeserializeObject <List <Lesson> >(File.ReadAllText("Lessons.json")); DataContext = this; StartLessonCommand = new Command <int>(ChooseLesson); var currentLesson = Lessons.Where(x => x.LessonNr == Settings1.Default.CurrentLesson); Lesson = currentLesson.Any() ? currentLesson.First() : Lessons.First(); }