//Cap nhat chi tiet hoa don
        public bool UpdateDetailReceipt(string idReceipt, string idStaff, string idItem, string pSaleOff, string pNum, string pPriceOut, string pIntoMoney, string pStatus)
        {
            try
            {
                DetailReceipt check = db.DetailReceipts.Where(t => t.IDRECEIPT == int.Parse(idReceipt) && t.IDSTAFF == int.Parse(idStaff) && t.IDITEM == int.Parse(idItem)).FirstOrDefault();
                if (check != null)
                {
                    //Cap nhat
                    check.SALEOFF   = float.Parse(pSaleOff);
                    check.NUMBER    = int.Parse(pNum);
                    check.PRICEOUT  = float.Parse(pPriceOut);
                    check.INTOMONEY = float.Parse(pIntoMoney);
                    check.STATUS    = int.Parse(pStatus);

                    db.SubmitChanges();
                    return(true);
                }
                else
                {
                    return(false);
                }
            }
            catch
            {
                return(false);
            }
        }
 //Xoa mot chi tiet hoa don
 public bool DeleteDetailReceipt(string idReceipt, string idStaff, string idItem)
 {
     try
     {
         DetailReceipt check = db.DetailReceipts.Where(t => t.IDRECEIPT == int.Parse(idReceipt) && t.IDSTAFF == int.Parse(idStaff) && t.IDITEM == int.Parse(idItem)).FirstOrDefault();
         if (check != null)
         {
             db.DetailReceipts.DeleteOnSubmit(check);
             db.SubmitChanges();
             return(true);
         }
         else
         {
             return(false);
         }
     }
     catch
     {
         return(false);
     }
 }
        //Them mot chi tiet hoa don
        public bool AddDetailReceipt(string idReceipt, string idStaff, string idItem, string pSaleOff, string pNum, string pPriceOut, string pIntoMoney, string pStatus)
        {
            try
            {
                DetailReceipt add = new DetailReceipt();
                add.IDRECEIPT = int.Parse(idReceipt);
                add.IDSTAFF   = int.Parse(idStaff);
                add.IDITEM    = int.Parse(idItem);
                add.NUMBER    = int.Parse(pNum);
                add.PRICEOUT  = float.Parse(pPriceOut);
                add.INTOMONEY = float.Parse(pIntoMoney);
                add.SALEOFF   = float.Parse(pSaleOff);
                add.STATUS    = int.Parse(pStatus);

                db.DetailReceipts.InsertOnSubmit(add);
                db.SubmitChanges();
                return(true);
            }
            catch
            {
                return(false);
            }
        }