如何在 Django ModelAdmin 中创建和保存动态字段？

Posted 2023-02-17

【中文标题】如何在 Django ModelAdmin 中创建和保存动态字段？

【英文标题】：How do I create and save dynamic fields in Django ModelAdmin?

【发布时间】：2015-09-01 15:21:08

【问题描述】：

我有一些模型：

class GroupType(models.Model):
    name = models.CharField(max_length=255)

class Group(models.Model):
    name = models.CharField(max_length=255)
    group_type = models.ForeignKey(GroupType)

class Person(models.Model):
    name = models.CharField(max_length=255)
    groups = models.ManyToManyField(Group, related_name="+")

但在 ModelAdmin 中，我想为每个组类型动态添加字段。因此，如果我有两个组类型public、private，我希望管理表单显示两个字段public_groups 和private_groups，而不是实际的数据库字段groups。

更多信息

我尝试创建自定义表单来动态添加字段：

class PersonAdminForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(PersonAdminForm, self).__init__(*args, **kwargs)
        new_fields = 
        for group_type in GroupType.objects.all():
            field_name = "0_groups".format(group_type.name.lower())
            qs = Group.objects.filter(group_type=group_type)
            field_field = forms.ModelMultipleChoiceField(queryset=qs)
            new_fields[field_name] = field_field
        self.fields.update(new_fields)

    class Meta:
        model = Person
        fields = '__all__'

就将字段添加到表单而言，这似乎起到了作用。但是保存这些字段并将它们添加到PersonAdmin 不起作用。如果我将字段显式添加到PersonAdmin 上的fields 属性，我会得到：

FieldError: Unknown field(s) (public_groups, private_groups) specified for Person. Check fields/fieldsets/exclude attributes of class PersonAdmin.

在尝试通过自定义 get_formsets 方法“动态”添加它们时，我也得到了同样的结果：

def get_fieldsets(self, request, obj=None):
    fieldsets = super(PersonAdmin, self).get_fieldsets(request, obj)
    print(self.form.fields)
    fieldsets[0][1]['fields'].extend(['public_groups', 'private_groups'])
    return fieldsets

【参考方案1】：

以下代码完美运行。 ModelForm 上重写的 __init__ 和 clean 方法添加了动态字段并定义了值的保存方式。

覆盖的get_form 和get_fieldsets 以及AdminModel 上的fieldsets 属性确保动态表单字段显示在管理员中。

class PersonAdminForm(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(PersonAdminForm, self).__init__(*args, **kwargs)
        new_fields = 
        initial = self.instance.groups.all()
        for group_type in GroupType.objects.all():
            field_name = '0_groups'.format(group_type.name.lower())
            qs = Group.objects.filter(group_type=group_type)
            field = forms.ModelMultipleChoiceField(
                queryset=qs,
                required=False,
                initial=initial,
            )
            new_fields[field_name] = field
        self.fields.update(new_fields)

    def clean(self):
        cleaned_data = super(PersonAdminForm, self).clean()
        groups = []
        for group_type in GroupType.objects.all():
            gt_name = '0_groups'.format(group_type.name.lower())
            groups.extend(cleaned_data.get(gt_name))
        self.instance.groups.clear()
        self.instance.groups.add(*groups)
        return cleaned_data

    class Meta:
        model = Person
        fields = '__all__'


@admin.register(Person)
class PersonAdmin(admin.ModelAdmin):
    form = PersonAdminForm

    # using the fieldsets attribute instead of fields in order to dynamically
    # add group type fields later.
    fieldsets = (
        (None, 
            'fields': (
                'name',
            ),
        ),
    )

    def get_form(self, request, obj=None, **kwargs):
        kwargs['fields'] = flatten_fieldsets(self.declared_fieldsets)
        return super(PersonAdmin, self).get_form(request, obj, **kwargs)

    def get_fieldsets(self, request, obj=None):
        fieldsets = super(PersonAdmin, self).get_fieldsets(request, obj)
        newfieldsets = list(fieldsets)
        fields = []
        for group_type in GroupType.objects.all():
            fields.append('0_groups'.format(group_type.name.lower()))
        newfieldsets.append(['Groups', 'fields': fields])
        return newfieldsets