Django模型形式继承和元继承

Question

我有这个模型：

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.

这个子模型：

^{pr2}$

UpgradedEvent是Event模型的子级，但是有一些额外的字段。 如何将Event窗体中的所有设置继承到UpgradedEvent窗体中？在

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

EDIT

看看答案，它很有用，但请记住： 您需要在子类中创建FormHelper的另一个实例，否则它将无法工作。所以儿童班应该看起来像：

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

创建FormWithSettings，它将保存窗体类的公共设置并继承它

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

Answer 2

您可以获得上面的Meta字段，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，我们可以通过在super(UpgradedEventForm, self)调用之后执行一些额外的操作，向__init__函数添加额外的过程，wwe可以访问父级的属性，并扩展这些属性。在

注意，最好用Form后缀命名表单，因为现在模型与表单冲突。因此，您的Form似乎有一个对Form本身的引用作为模型。通过使用正确的“命名法”，可以避免很多错误。在