You can do this very easily by tweaking your model as follows: 1. Override __init__() and store the value of that field in a temporary value, such as self.old_status.
2. Override save() and before you call the super() save, check if self.pk (meaning the instance is not new). If so, and self.old_status != self.current_status, you can raise an exception. For extra credit you might want to tweak your ModelForm so that it will raise a ValidationError, because otherwise it'll validate and then you'll get a 500 error when the save() on the model is attempted. However, I like having the exception raised at the model level because it will protect your data in case the model is accessed by some means other than your ModelForm. Shawn -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-us...@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
