django admin - populate field with callable

I can't find a single example of anyone doing this apart from this example, which doesn't help me other than to know where the code needs to sit.

How to prepopulate UserProfile fields in the Django admin?

so this is my code

class QuoteMaterial(models.Model):
    name = models.CharField(_('name'), max_length=255)
    content = models.TextField(_('content'),
                           help_text=_('A static priced item used when doing a job. Selectable when creating a quote. '))
    price = models.DecimalField(_('price'), max_digits=6, help_text="not sure if this is before or after VAT yet", decimal_places=2, default="0.00")

    def get_companies():
        return CompanyProfile.objects.filter(user=request.user)

    company = models.ForeignKey(CompanyProfile, default=get_companies) 

If its not obvious, im trying in the admin section to populate a 开发者_开发百科dropdown with the available companies that belong to the user that is logged in.

my problem is that i dont know how to pass the request object to "get_companies". anyone know of any examples.

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You will have to do this overriding in your admin class that extends the ModelAdmin, not in your class that extends models.Model. Specifically, you need to override formfield_for_foreignkey.

From the docs:

class MyModelAdmin(admin.ModelAdmin):
    def formfield_for_foreignkey(self, db_field, request, **kwargs):
        if db_field.name == "car":
            kwargs["queryset"] = Car.objects.filter(owner=request.user)
    return super(MyModelAdmin, self).formfield_for_foreignkey(db_field, request, **kwargs)

For your case, it would seem like:

if db_field.name == "company":
    kwargs['queryset'] = request.user.company_set.all()

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You're mixing up terms.

"Prepopulating" means to fill in a field from another field. It's not how you filter things for the admin popups, since you aren't actually setting the field, but simply limiting choices and letting the user set the field from those.

Aditionally, the default value for a field needs to be a constant, since this is passed down to the database, which can't use a query to set a default.

What you really want is something like the limit_choices_to (docs) parameter for your ForeignKey, but even then, you can't use request for this; it has to work using fields in the model. The reason for this is that, if you based it on the user, then some users would be unable to select the current value set by another user. You don't want company changing itself when the user just wants to change content, for example, just because user doesn't yield the current company in the filter.