使用django上相同型号的信号保存

我想在图1上合并这些方法，这样我就可以得到图2，并使用信号将结果保存在同一个模型上。出现问题，因此结果未保存在模型上

图1：

class Invoice(models.Model):

    date = models.DateField(default=timezone.now)
    amount_gtotal = models.DecimalField(max_digits=20, decimal_places=2, default=0)
    amount_gtax = models.DecimalField(max_digits=20, decimal_places=2, default=0)
    amount_gamount = models.DecimalField(max_digits=20, decimal_places=2, default=0)

    def amount_gtotal(self):
        items = self.invoiceitem_set.all()
        amount_gtotal = 0.00
        for item in items:
            amount_gtotal += item.price * item.quantity
        return amount_gtotal

    def amount_gtax(self):
        items = self.invoiceitem_set.all()
        amount_gtax = 0
        for item in items:
            amount_gtax += item.price_sell * item.quantity * item.vat
        return amount_gtax

    def amount_gamount(self):
        amount_gamount = self.amount_gtotal() + self.amount_gtax()
        return amount_gamount

图2：

    def calculate(self):

        invoiceitems = self.invoiceitem_set.all()

        amount_gtotal = 0
        amount_gtax = 0
        amount_gamount = 0

        for invoiceitem in invoiceitems:
            amount_gtotal += item.price * item.quantity
            amount_gtax += item.price_sell * item.quantity * item.vat
            amount_gamount += amount_gtotal + amount_gtax

        totals = {
            'amount_gtotal': amount_gtotal,
            'amount_gtax': amount_gtax,
            'amount_gamount': amount_gamount,
        }

        for k,v in totals.items():
            setattr(self, k, v)
            if save == True:
                self.save()
        return totals

def invoice_pre_save(sender, instance, *args, **kwargs):
    instance.calculate()

pre_save.connect(invoice_pre_save, sender=Invoice)


class InvoiceItem(models.Model):
    invoice = models.ForeignKey('Invoice', on_delete=models.CASCADE)
    product = models.ForeignKey(Product, on_delete=models.PROTECT)
    price_sell = models.DecimalField(max_digits=20, decimal_places=2)
    quantity = models.DecimalField(max_digits=20, decimal_places=2)
    vat = models.DecimalField(max_digits=5, decimal_places=2)

---

我想在图1上合并这些方法，这样我就可以得到图2，并使用信号将结果保存在同一个模型上。出现问题，因此结果未保存在模型上

我认为您需要在calculate func中为save变量传递一个默认参数，如下所示：

def calculate(self, save=False):

def invoice_pre_save(sender, instance, *args, **kwargs):
    instance.calculate(save=False)

pre_save.connect(invoice_pre_save, sender=Order)

然后在信号函数中，您可以再次通过保存，如下所示：

def calculate(self, save=False):

def invoice_pre_save(sender, instance, *args, **kwargs):
    instance.calculate(save=False)

pre_save.connect(invoice_pre_save, sender=Order)

---

现在，您应该能够调用calulate（save=True）

我尝试过，但一半的解决方案是，当我创建发票时，它不会保存其字段上的值，但我会更新发票而不做任何更改，它会更新发票，表上的值也会更新为。也许您需要尝试更改calculate func中的var，并改用它。事实上，calculate func应重新运行未定义的变量我已发布了可能的解决方案，请检查！