public ActionResult OnPost(List <ExternalBillItems> Bi)
        {
            Customer Customer = _db.Customer.FirstOrDefault(c => c.CompanyName == CustomerName);

            ExternalBillHeader.CustId = Customer.Id;
            StatusMessage             = _SalesTrans.CreateExternalBill(ExternalBillHeader, Bi, SelectedWh, "New", null).GetAwaiter().GetResult();

            ModelState.Clear();

            return(RedirectToPage("/Sales/ExternalBillings/Details", new { BhId = ExternalBillHeader.Id }));
            // return Page();
        }
        public ActionResult OnPost(List <ExternalBillItems> Bi, int CustomerId, int WhId)
        {
            ExternalBillHeader.CustId = CustomerId;
            int BhId = ExternalBillHeader.Id;

            // creating new bill (will create a new bill similar to the older one, after that the old one will be deleted)
            StatusMessage = _SalesTrans.CreateExternalBill(ExternalBillHeader, Bi, WhId, "Edit", BhId).GetAwaiter().GetResult();


            ModelState.Clear();

            if (ExternalBillHeader.Id != 0)
            {
                return(RedirectToPage("/Sales/ExternalBillings/Details", new { BhId = ExternalBillHeader.Id }));
            }
            else
            {
                return(RedirectToPage("/Sales/ExternalBillings/Create"));
            }
        }