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.

而这个子 ModelForm：

class UpgradedEvent(Event):

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

    class Meta(Event.Meta):
        model = UpgradedEvent

UpgradedEvent是Event 模型的孩子，但有一些额外的字段。如何将EventFORM 中的所有设置继承到UpgradedEventFORM 中？

运行上面的代码时，它会呈现Event表单。有没有办法只继承里面的设置__init__？

编辑

查看答案，它很好用，但请记住：您需要FormHelper在子类中创建另一个实例，否则将无法工作。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

您可以获取上述字段Meta，并扩展列表等：

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__init__通过在super(UpgradedEventForm, self)调用后执行一些额外的操作来为函数添加额外的过程，并且我们可以访问我们父级的属性，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。结果，您Form似乎有一个对Form自身的引用作为模型。通过使用正确的“命名法”，您可以避免很多错误。

Answer 2

创建FormWithSettings将为您保存通用设置的表单类并继承它

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