Question

我有一些带有用户字段的模型。

为此，我想创建一个表单mixin，它将添加self.user实例（在视图中提供给表单）。有可能吗？

这是示例

class UserFormMixin(object):
    """Removes user instance from kwargs and adding it to object"""
    def __init__(self, *args, **kwargs):
        super(UserFormMixin, self).__init__(*args, **kwargs)
        self.user = kwargs.pop('user')

    def save(self, **kwargs):
        obj = super(UserFormMixin, self).save(commit=False)
        obj.user = self.user
        if kwargs['commit']:
            return obj.save()
        else:
            return obj

我想要实现的目标：

class SomeFormWithUserField(UserFormMixin, ModelForm):
    class Meta:
        model = SomeModelWithUserField
        fields = ['fields without user']

    def save(self, **kwargs):
        data = super(SomeFormWithUserField, sefl).save(commit=False)
        #data already with user prepended
        #do some other stuff with data
        if kwargs['commit']:
            return data.save()
        else
            return data

class SomeOtherFormWithUser(UserFormMixin, ModelForm):
    class Meta:
        model = SomeOtherModel
        fields = ['some fields without user']

# no need to save here.. standard model form with user prepended on save()

问题是UserFormMixin不了解模型实例？或者我错在这里？我遇到了一些问题..比如'commit'kwargs key error ..或者对象没有保存..

Answer 1

你很接近，你只是有一些逻辑错误。首先，为了覆盖ModelForm方法，您的mixin需要从ModelForm继承。

class UserFormMixin(forms.ModelForm):
    ...

然后，从中继承的任何表单都会继承UserFormMixin，而不是ModelForm。

class SomeOtherFormWithUser(UserFormMixin):
    ...

其次，您的__init__方法覆盖不正确。你需要接受传递给它的任何和所有的args和kwargs。

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

最后，不要在子类中再次覆盖save方法。我想它在技术上不会伤害任何东西，但是如果你要重复代码，那么继承的重点是什么呢？如果user不可为空，则在将其添加到模型之前，您始终可以添加if块以检查self.user is not None是否为user。当然，如果self.user不可为空，那么无论如何都不会在没有{{1}}的情况下保存您的模型。

Answer 2

这个似乎工作得很好。谢谢克里斯！如果这可以更好地编码，请告诉我。

class UserFormMixin(forms.ModelForm):
    """Removes user instance from kwargs and adding it to object"""
    def __init__(self, *args, **kwargs):
        super(UserFormMixin, self).__init__(*args, **kwargs)
        self.user = kwargs.pop('user')

    def save(self, commit=True):
        obj = super(UserFormMixin, self).save(commit=False)
        obj.user = self.user
        if commit:
            return obj.save()
        else:
            return obj


class SomeFormWithUserField(UserFormMixin):
    class Meta:
        model = SomeModelWithUserField
        fields = ['fields without user']

    def save(self, **kwargs):
        data = super(SomeFormWithUserField, sefl).save(commit=False)
        #data already with user prepended
        #do some other stuff with data
        # self.send_mail() f.e.
        return data.save()

class SomeOtherFormWithUser(UserFormMixin):
    class Meta:
        model = SomeOtherModel
        fields = ['some fields without user']
# this will work too

ModelForm用户Mixin

2 个答案: