filter foreignkey field in django admin

Question

I have these models:

class Entity(models.Model):
       name=models.CharField(max_length=100)
      
class Theme(models.Model):
   name=models.CharField(max_l         


        

Answer 1

A bit unrelated, but similar to this so I'll post this here.

I was looking for a way to remove the NULL choice selection on a ModelForm foreignkey field. I first thought I could filter the queryset as is done in other answers here, but that didn't work.

I found that I can filter the entry where the pk value is NULL like this in the get_form method:

class CompanyAdmin(admin.ModelAdmin):
    def get_form(self, request, obj=None, **kwargs):
        form = super().get_form(request, obj, **kwargs)
        # remove null choice
        form.base_fields["theme"].choices = ((pk, display) for pk, display in form.base_fields["theme"].choices if pk)
        return form