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

                    ServiceDataProvider.DeleteProfessor(professor.ProfessorId);
                    Professors.Remove(professor);
                }
                catch (FaultException <DeleteFault> fe)
                {
                    MessageBox.Show(string.Format("{0} {1}", fe.Detail.Message, fe.Detail.Description));
                }
            }
        }