public async Task <IActionResult> Create([Bind("Id,ProductCode,Name,Description,Price")] Product product)
        {
            if (ModelState.IsValid)
            {
                _context.Add(product);
                await _context.SaveChangesAsync();

                return(RedirectToAction(nameof(Index)));
            }
            return(View(product));
        }
        public async Task <IActionResult> Create([Bind("Id,CustomerCode,CustomerType,Name,Web,Email,PhoneNumber")] Customer customer)
        {
            if (ModelState.IsValid)
            {
                _context.Add(customer);
                await _context.SaveChangesAsync();

                return(RedirectToAction(nameof(Index)));
            }
            return(View(customer));
        }
        public async Task <IActionResult> Create([Bind("SerialNumber,InvoiceNumber,InvoiceDate,SelectedCustomerId")] Invoice invoice)
        {
            ModelState.Clear();
            var customer = await _context.Customer.FirstOrDefaultAsync(c => c.Id == invoice.SelectedCustomerId);

            if (customer is null)
            {
                ModelState.AddModelError("SelectedCustomerId", "Unable to find customer");
                return(View(invoice));
            }

            invoice.Customer = customer;

            if (ModelState.IsValid)
            {
                invoice.DueDate = invoice.InvoiceDate.AddDays(DueDays);

                _context.Add(invoice);
                await _context.SaveChangesAsync();

                return(RedirectToAction(nameof(Index)));
            }
            return(View(invoice));
        }