You need to set a RelatedFieldWidgetWrapper wrapper in your model form:
The RelatedFieldWidgetWrapper (found in django.contrib.admin.widgets) is used in the Admin pages to include the capability on a Foreign Key control to add a new related record. (In English: puts the little green plus sign to the right of the control.)

class MyCustomUserCreationForm(models.ModelForm)
    ...
    location = forms.ModelChoiceField(queryset=Location.objects.all())

    def __init__(self, *args, **kwargs):
        super(MyCustomUserCreationForm, self).__init__(*args, **kwargs)
        rel = ManyToOneRel(self.instance.location.model, 'id') 
        self.fields['location'].widget = RelatedFieldWidgetWrapper(self.fields['location'].widget, rel, self.admin_site)

I could make a mistake in the example code, so see these posts and examples:

• RelatedFieldWidgetWrapper
• More RelatedFieldWidgetWrapper – My Very Own Popup
• Django admin - How can I add the green plus sign for Many-to-many Field in custom admin form
• How can I manually use RelatedFieldWidgetWrapper around a custom widget?
• Django: override RelatedFieldWidgetWrapper

我已经根据上面的答案创建了方法：

def add_related_field_wrapper(form, col_name):
    rel_model = form.Meta.model
    rel = rel_model._meta.get_field(col_name).rel
    form.fields[col_name].widget = 
    RelatedFieldWidgetWrapper(form.fields[col_name].widget, rel, 
    admin.site, can_add_related=True, can_change_related=True)

然后从我的窗体调用这个方法：

class FeatureForm(forms.ModelForm):
    offer = forms.ModelChoiceField(queryset=Offer.objects.all(), required=False)
    package = forms.ModelChoiceField(queryset=Package.objects.all(), required=False)
    def __init__(self, *args, **kwargs):
        super(FeatureForm, self).__init__(*args, **kwargs)
        add_related_field_wrapper(self, 'offer')
        add_related_field_wrapper(self, 'package')

这在Django 1.8.2上运行良好。

Google在搜索如何在具有外键关系的自定义表单中的字段旁边获得“+”图标时向我指出了这个页面，所以我想我应该添加。
对我来说，使用django-autocomplete-light很好地完成了这个任务，使用了“添加另一个”功能。

你甚至不需要走那么远，此外，这些答案可能是过时的，因为他们没有为我工作的任何能力。
我解决这个问题的方法是，只要您的模型中已经有了ForeignKey字段，那么您就可以创建自定义ModelChoiceField：

class LocationModelChoiceField(forms.ModelChoiceField):
    def label_from_instance(self, obj):
        return "%" % (obj.name)

接下来的关键是NOT为ModelForm中的ModelChoiceField创建自定义字段（即 location = forms.ModelChoiceField（Location.objects.all（）））
换句话说，把它去掉，在ModelForm中有这样的内容：

class UserAdminForm(forms.ModelForm):

    class Meta:
        model = User
        fields = '__all__'

最后，在ModelAdmin中：

class UserAdmin(admin.ModelAdmin):
    model = User
    form = UserAdminForm

    def formfield_for_foreignkey(self, db_field, request, **kwargs):
        if db_field.name == 'location':
        return LocationModelChoiceField(queryset=Location.objects.order_by('name')) # if you want to alphabetize your query
    return super().formfield_for_foreignkey(db_field, request, **kwargs)

替代方法：使用**.remote_field**代替rel

def add_related_field_wrapper(self,form, col_name):
    rel_model = form.Meta.model
    rel = rel_model._meta.get_field(col_name).remote_field
    form.fields[col_name].widget = RelatedFieldWidgetWrapper(form.fields[col_name].widget, rel, admin.site, can_add_related=True, can_change_related=True)

def __init__(self, *args, **kwargs):
    super(CustomerAdminForm, self).__init__(*args, **kwargs)
    self.add_related_field_wrapper(self, 'offer')
    self.add_related_field_wrapper(self, 'package')

谢谢你，