public BaoCaoDatHangBusiness()
 {
     dbContext         = new SMSEntities();
     _phieuDatHangRepo = new PhieuDatHangRepository(dbContext);
     _nhanVienRepo     = new NhanVienRepository(dbContext);
     _hangHoaRepo      = new HangHoaRepository(dbContext);
     _nhanVienBus      = new NhanVienBusiness();
 }