public CongNoNXB(CONGNONXB congno)
 {
     MaSoSach = congno.masosach;
     MaSoNXB = congno.masonxb;
     SoLuong = congno.soluong;
     DonGia = congno.dongia;
     Thang = congno.thang;
 }
 public static int add(CongNoNXB congno)
 {
     try
     {
         using (EntitiesDataContext db = new EntitiesDataContext())
         {
             CONGNONXB cn;
             cn = (from c in db.CONGNONXBs
                   where c.masonxb.Equals(congno.MaSoNXB)
                   && c.masosach.Equals(congno.MaSoSach)
                   && c.thang.Month.Equals(congno.Thang.Month)
                   && c.thang.Year.Equals(congno.Thang.Year)
                   select c).SingleOrDefault();
             if (cn != null)
             {
                 cn.soluong += congno.SoLuong;
                 db.SubmitChanges();
                 return 1;
             }
             else
             {
                 cn = new CONGNONXB();
                 cn.masonxb = congno.MaSoNXB;
                 cn.masosach = congno.MaSoSach;
                 cn.soluong = congno.SoLuong;
                 cn.dongia = congno.DonGia;
                 cn.thang = congno.Thang;
                 db.CONGNONXBs.InsertOnSubmit(cn);
                 db.SubmitChanges();
                 return 1;
             }
         }
     }
     catch (Exception ex)
     {
         Console.WriteLine(ex.Message);
         return 0;
     }
 }
 partial void DeleteCONGNONXB(CONGNONXB instance);
 partial void UpdateCONGNONXB(CONGNONXB instance);
 partial void InsertCONGNONXB(CONGNONXB instance);
		private void detach_CONGNONXBs(CONGNONXB entity)
		{
			this.SendPropertyChanging();
			entity.SACH = null;
		}
		private void attach_CONGNONXBs(CONGNONXB entity)
		{
			this.SendPropertyChanging();
			entity.SACH = this;
		}
 public CongNoNXB(CONGNONXB congno, NXB nxb, SACH sach)
     : this(congno,nxb)
 {
     Sach = new Sach(sach);
 }
 public CongNoNXB(CONGNONXB congno, NXB nxb)
     : this(congno)
 {
     NXB = new NhaXuatBan(nxb);
 }