private void ExecuteEdit(object p)
        {
            if (p != null && p is Professor)
            {
                var professor = p as Professor;

                AddProfessorView profView = new AddProfessorView(professor);
                profView.ShowDialog();
            }
        }
        private void ExecuteOpening(object p)
        {
            AddProfessorView profView = new AddProfessorView();

            profView.ShowDialog();
        }