public ObservableCollection <LessonModel> GetListLesson(TabName tabname)
{
ObservableCollection <LessonModel> result = null;
result = new ObservableCollection <LessonModel>(CommonDAO.GetListLesson(tabname));
foreach (LessonModel lesson in result)
{
if (string.IsNullOrEmpty(lesson.LastLearning))
{
lesson.IsSelected = true;
break;
}
}
return(result);
}