How is this possible to call OneToOneField values in admin using list_display=[]

Question

my model

    class user_profile(models.Model):

    user = models.OneToOneField(User, on_delete=models.CASCADE)
    age = models.IntegerField()

    profile_created = models.DateTimeField(auto_now_add=True, auto_now=False)
    timestamp = models.DateTimeField(auto_now=True, auto_now_add=False)

admin.py

class UserProfileAdmin(admin.ModelAdmin):
list_display = ['user','user.username','profile_created', 'timestamp']
admin.site.register(user_profile, UserProfileAdmin)

It show the following error(s):

ERRORS: <class 'testapp.admin.UserProfileAdmin'>: (admin.E108) The value of 'list_display[1]' refers to 'user.username', which is not a call able, an attribute of 'UserProfileAdmin', or an attribute or method on 'testapp.user_profile'.

How can I fetch another table values in admin.py?

Answer 1

As per the PEP8, class names should normally use the CapWords convention.

class UserProfile(models.Model):
    # your code

also, to show the username in DjangoAdmin, you should define a method as,

from django.core.exceptions import ObjectDoesNotExist


class UserProfileAdmin(admin.ModelAdmin):
    list_display = ['user', 'username', 'profile_created', 'timestamp']

    def username(self, instance): # name of the method should be same as the field given in `list_display`
        try:
            return instance.user.username
        except ObjectDoesNotExist:
            return 'ERROR!!'

admin.site.register(UserProfile, UserProfileAdmin)