public void ClearDisplayData()
 {
     QualificationList.Clear();
     QualificationOpeningList.Clear();
     QualificationCertificateList.Clear();
     QualificationPrerequisitesList.Clear();
 }
        private void DisplayOpenings(string qualificationId)
        {
            QualificationOpeningList.Clear();

            var openings = new OpeningService(MainWindow.MainContext).GetQualificationOpenings(qualificationId)
                           .Select(c => new QualificationOpeningViewModel(c));

            foreach (var opening in openings)
            {
                QualificationOpeningList.Add(opening);
            }
        }