protected override async Task UpdateModels()
{
if (Courses == null)
{
Courses = new MvxObservableCollection <CourseDTO>(await _coursesProvider.GetCoursesAsync(CourseGroupDTO.Id));
}
else
{
Courses.Clear();
Courses.AddRange(await _coursesProvider.GetCoursesAsync(CourseGroupDTO.Id));
}
}
