Display created/modified fields of django_extensions in admin interface

Question

I have a class based on TimeStampedModel from django-extentions:

from model_utils.models import TimeStampedModel


class MyClass(TimeStampedModel):
    pass

By default in the admin interface the created and modified fields are not displayed in the edition page my_app/myclass/id.

I tried this hack to force the display of the created and modified fields in the edit admin page for MyClass:

from django.contrib import admin

from my_app.models import MyClass


class MyClassAdmin(admin.ModelAdmin):
    fields = MyClass._meta.get_all_field_names()

admin.site.register(MyClass, MyClassAdmin)

But this raised the following exception:

Exception Type:     FieldError
Exception Value:    Unknown field(s) (modified, created) specified for MyClass. Check fields/fieldsets/exclude attributes of class MyClassAdmin.

Any idea how can I display the created and modified fields in the MyClass edition admin interface?

Note 1: MyClass is a model with a lot of fields including ManyToMany fields. I can display all the fields except the created and modified fields from the base class TimeStampedModel.

Note 2: The admin page in reference is the edition page of a row: my_app/myclass/id

Answer 1

The solution is to use the readonly_fields attribute:

from django.contrib import admin

from my_app.models import MyClass


class MyClassAdmin(admin.ModelAdmin):
    readonly_fields = ('created', 'modified', )

admin.site.register(MyClass, MyClassAdmin)

Answer 2

Created and Modified are self-managed fields. I think that "hack" the functionality is not good idea. You can display these fields in list display as follow:

For many to many problem:

def <funcname>(self, obj):
    return ', '.join([object.<object_field_you_want_to_display> for object in obj.<manyTomanyField>.all()])

<funcname>.short_description = 'Wanted name for column'

Then in list_display:

list_display = (...., '<funcname>')

And then you want to display all fields you want (created and modified too)

list_display(...all fields you want ..., '<funcname>', 'created', 'modified')

But if you still think that it's good idea you should add these fields in your template (/includes/fieldset.html). But you should first write context processor and/or template tag to get the write value ... and so on...