private void UpdateSubjects()
 {
     SubjectGrid.Items.Clear();
     _subjectsCollection.Clear();
     foreach (var group in InitSubjectsTable())
     {
         var val = new SubjectRow(group.Key);
         SubjectGrid.Items.Add(val);
     }
 }
 private void UpdateSubjects()
 {
     SubjectGrid.Items.Clear();
     _subjectsCollection.Clear();
     foreach (var group in InitSubjectsTable())
     {
         var val = new SubjectRow(group.Key);
         SubjectGrid.Items.Add(val);
     }
 }