private string GetInvoiceNumber()
        {
            var    purchaseLastEntry = context.PurchaseProduct.GetLastOrDefault();
            string invoiceNumber     = AutoGeneratedNumber.GetStockNumber(purchaseLastEntry == null ? "1" : purchaseLastEntry.InvoiceNumber);

            return(invoiceNumber);
        }
        private string InvoiceNumber()
        {
            var    lastSalesInvoice = context.SalesInvoice.GetLastOrDefault();
            string invoiceNumber    = AutoGeneratedNumber.GetInvoiceNumber(lastSalesInvoice == null ? "1": lastSalesInvoice.InvoiceNumber);

            return(invoiceNumber);
        }