Django ModelForm 继承和 Meta 继承

Question

我有这个 ModelForm：

class Event(forms.ModelForm):

    def __init__(self, *args, **kwargs):
        super(Event, self).__init__(*args, **kwargs)
        ##Here make some changes such as:
        self.helper = FormHelper()
        self.helper.form_method = 'POST'
        ##Many settings here which **i don't want to rewrite in 10 child classes**

    class Meta:
        model = Event
        exclude = something...
        widgets = some settings here also.

还有这个子 ModelForm：

class UpgradedEvent(Event):

    def __init__(self, *args, **kwargs):
        super(UpgradedEvent,self).__init__(*args,**kwargs)

    class Meta(Event.Meta):
        model = UpgradedEvent

UpgradedEvent 是Event model 的子级，但有一些额外的字段。 如何将Event FORM 中的所有设置继承到UpgradedEvent FORM 中？

运行上述代码时，它会呈现Event 表单。有没有办法只继承__init__ 中的设置？

编辑

查看答案，效果很好，但请记住： 您需要在您的子类中创建另一个 FormHelper 实例，否则它将不起作用。所以子类应该是这样的：

class UpgradedEvent(Event):

    def __init__(self, *args, **kwargs):
        super(UpgradedEvent,self).__init__(*args,**kwargs)
        self.helper = FormHelper()

    class Meta(Event.Meta):
        model = UpgradedEvent

Answer 1

可以获取上面Meta的字段，扩展列表等：

class UpgradedEventForm(EventForm):

    def __init__(self, *args, **kwargs):
        super(UpgradedEventForm,self).__init__(*args,**kwargs)
        # some extra settings
        # ...
        # for example
        self.fields['extra_field'].initial = 'initial value of extra field'

    class Meta(EventForm.Meta):
        model = UpgradedEvent
        exclude = EventForm.Meta.exclude + ['extra_exclude1', 'extra_exclude2']
        fields = EventForm.Meta.fields + ['extra_field']

因此，通过使用继承，我们可以通过在super(UpgradedEventForm, self) 调用之后执行一些额外的操作来为__init__ 函数添加额外的过程，并且我们可以访问父级的属性并扩展这些属性。

请注意，您最好使用Form 后缀命名您的表单，因为现在您的模型与您的表单发生冲突。因此，您的 Form 似乎具有对 Form 本身的引用作为模型。通过使用正确的“命名法”，您可以避免很多错误。

Answer 2

创建FormWithSettings，它将为您的表单类保存通用设置并继承它

class FormWithSettings(forms.ModelForm):

    def __init__(self, *args, **kwargs):
        super(FormWithSettings, self).__init__(*args, **kwargs)
        ##Here make some changes such as:
        self.helper = FormHelper()
        self.helper.form_method = 'POST'
        ##Many settings here which **i don't want to rewrite in 10 child classes**

    class Meta:
        exclude = something...
        widgets = some settings here also.

class EventForm(FormWithSettings):

    def __init__(self, *args, **kwargs):
        super(EventForm, self).__init__(*args,**kwargs)

    class Meta(FormWithSettings.Meta):
        model = Event

class UpgradedEventForm(FormWithSettings):

    def __init__(self, *args, **kwargs):
        super(UpgradedEventForm, self).__init__(*args,**kwargs)

    class Meta(FormWithSettings.Meta):
        model = UpgradedEvent