Use raw_id_fields widget in custom ModelForm

raw_id_fields_widget_in_custom_ModelForm.py

from django.contrib.admin import widgets
from django import forms
from django.contrib import admin

# create wrappers for overriding the queryset

class ToWrapper(object):
    def __init__(self, to, manager):
        self.to = to
        self._default_manager = manager

    def __getattr__(self, name):
        return getattr(self.to, name)

class RelWrapper(object):
    def __init__(self, rel, manager):
        self.rel = rel
        self.to = ToWrapper(rel.to, manager)

    def __getattr__(self, name):
        return getattr(self.rel, name)

class FooForm(forms.ModelForm):
    bar = forms.ModelChoiceField(queryset=Bar.all_objects,
            label=_("Bar"),
            widget=widgets.ForeignKeyRawIdWidget(
                RelWrapper(Foo._meta.get_field('bar').rel,
                    Bar.all_objects)))

    class Meta:
        model = Foo

class FooAdmin(admin.ModelAdmin):
    form = FooForm

Thanks a lot!

This is a very nice piece of code, but it does not work on Django 1.5. With which versions of Django does it work?

In Django 1.5 I see a few problems:

• first, the widget=widgets.ForeignKeyRawIdWidget(...) should receive a reference to a third argument admin.site
• second, the ForeignKeyRawIdWidget(...) uses the _default_manager only for rendering the current value, not for limiting the model queryset
• third, the ForeignKeyRawIdWidget(...) has an if ... block to check whether .rel.to is registered within the passed admin.site (which is not the case, because we instantiate .rel.to to the class ToWrapper

It would be great if it were possible to amend the code for Django 1.5, but I couldn't find an acceptable solution, so far

I'm using Django 1.6 and the follow seems to work fine:

class MyCustomForm(ModelForm):
    class Meta:
        model = MyModel
        widgets = {
            'field': ForeignKeyRawIdWidget(MyModel._meta.get_field("field_to_rel").rel, admin.site),
        }

And my ModelAdmin get_form returns MyCustomForm.

For Django>=2.0 you should use remote_field instead of rel.

Since Django 1.5 +, the ForeignKeyRawIdWidget require a site variable, which site should I pass to this object (foo or bar) and do you know if it's possible to use ForeignKeyRawIdWidget in a regular forms.Form?