public TeachingGroupService(ReportWriterContext context)
 {
     _context = context;
     TeachingGroupsSelectList = GetAll().Select(tg => new SelectListItem
     {
         Value = tg.Id.ToString(),
         Text  = tg.Name
     }).ToList();
 }
 public StudentService(ReportWriterContext context)
 {
     _context = context;
 }