Django disable editing (but allow adding) in TabularInline view

Question

I want to disable editing ALL objects within a particular TabularInline instance, while still allowing additions and while still allowing editing of the parent model.

I

Answer 1

You can try creating a separate inline class (see the InlineModelAdmin docs) that uses a custom ModelForm where you can customise the the clean method to throw an error when trying to update:

from django.contrib import admin
from django.core.exceptions import ValidationError
from django.forms import ModelForm

from myapp.models import Supervisee


class SuperviseeModelForm(ModelForm):
    class Meta(object):
        model = Supervisee
        # other options ...

    def clean(self):
        if self.instance.pk:
            # instance already exists
            raise ValidationError('Update not allowed')
        # instance doesn't exist yet, continue
        return super(SuperviseeModelForm, self).clean()


class SuperviseeInline(admin.TabularInline):
    model = Supervisee
    form = SuperviseeModelForm


class SuperviseeAdmin(admin.ModelAdmin):
    inlines = [SuperviseeInline]