Question

I try to display and add comment using Django admin, but Comment model use GenericForeignKey reference.

# in model.py
class Comment(models.Model):
    type      = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    object    = generic.GenericForeignKey('type')
    text      = models.TextField()

# in admin.py
class CommentAdmin(admin.ModelAdmin):
    list_display = ('type', 'object', 'text')
    fields = ('type', 'object', 'text')

admin.site.register(Comment, CommentAdmin)

But Django generate error:

‘CommentAdmin.fields’ refers to field ‘object’ that is missing from
the form.

How to fix it?

Answer 1

The GenericForeignKey isn’t a field in the database; it’s a helper to enable you with an api for the object you have defined through setting object_id and type, therefore you don’t need it in your form.

To fix it, simply take it out and put in object_id:

fields = ('type', 'object_id', 'text')