Django ModelForm 继承、子类化和传入实例

Question

我有一个地址模型:

class Address(models.Model):
  line1 = models.CharField(max_length=100)
  ....

和地址表单:

class AddressForm(forms.ModelForm):
  class Meta:
    model = Address

一些模型将有一个地址字段，因此我不想复制+粘贴 AddressForm 中的所有字段，而是想扩展 AddressForm 以便可以重用它。具体来说，我想避免将所有表单字段复制+粘贴到其他应用程序的表单中，并且只有一个 AddressForm.is_valid() 函数。

例如，订单将有一个地址，所以我的计划是这样做:

class Order:
  address = models.ForeignKey(Address, on_delete=models.CASCADE)

class OrderForm(AddressForm):
  class Meta:
    model = Order

但是，当我从 order/views.py 向 OrderForm 传递一个实例时，我传递的是 Order 的实例，并且所有 AddressForm 字段都显示为空白:

form = OrderForm(instance=order)

如何从 order.address 字段初始化 AddressForm 字段？

我试过这个:

class OrderForm(AddressForm):
    def __init__(self, *args, **kwargs):
        kwargs['instance'] = kwargs['instance'].address
        super(OrderForm, self).__init__(*args, **kwargs)

但是这不起作用。

有办法做到这一点吗？或者重用 AddressForm 的更好方法？或者只有当 Order 是 Address 的子类时这才有效？

干杯，

Answer 1

如果您不想子类化 Address，那么您应该在 View 中使用两个表单，而不是尝试在订单表单中包含地址字段。

if request.method = "POST":
    address_form = AddressForm(request.POST, instance=order.address)
    order_form = OrderForm(request.POST, instance=order)
    if address_form.is_valid() and order_form.is_valid():
        address = address_form.save()
        order = order_form.save()

您的订单表格应排除地址的外键。

class OrderForm(AddressForm):
    class Meta:
    model = Order
    exclude = ['address']

当您创建新实例时，您应该使用 commit=False 保存订单，设置地址，然后保存订单:

if request.method = "POST":
    address_form = AddressForm(request.POST)
    order_form = OrderForm(request.POST)
    if address_form.is_valid() and order_form.is_valid():
        address = address_form.save()
        order = order_form.save(commit=False)
        order.address = address
        order.save()