void RemoveElementHandler() { if (SelectedItem2 != null && Trainings.Any(t => t.Id == SelectedItem2.Id)) { Trainings.Remove(SelectedItem2); } }
void AddElementHandler() { if (SelectedItem != null && !Trainings.Any(t => t.Id == SelectedItem.Training.Id)) { Trainings.Add(SelectedItem.Training); } }