Pre-populate an inline FormSet?

by

So, you’re not going to like the answer, partly because I’m not yet done writing the code and partly because it’s a lot of work.

What you need to do, as I discovered when I ran into this myself, is:

  1. Spend a lot of time reading through the formset and model-formset code to get a feel for how it all works (not helped by the fact that some of the functionality lives on the formset classes, and some of it lives in factory functions which spit them out). You will need this knowledge in the later steps.
  2. Write your own formset class which subclasses from BaseInlineFormSet and accepts initial. The really tricky bit here is that you must override __init__(), and you must make sure that it calls up to BaseFormSet.__init__() rather than using the direct parent or grandparent __init__() (since those are BaseInlineFormSet and BaseModelFormSet, respectively, and neither of them can handle initial data).
  3. Write your own subclass of the appropriate admin inline class (in my case it was TabularInline) and override its get_formset method to return the result of inlineformset_factory() using your custom formset class.
  4. On the actual ModelAdmin subclass for the model with the inline, override add_view and change_view, and replicate most of the code, but with one big change: build the initial data your formset will need, and pass it to your custom formset (which will be returned by your ModelAdmin‘s get_formsets() method).

I’ve had a few productive chats with Brian and Joseph about improving this for future Django releases; at the moment, the way the model formsets work just make this more trouble than it’s usually worth, but with a bit of API cleanup I think it could be made extremely easy.

More Related Contents:

  1. How do I filter ForeignKey choices in a Django ModelForm?
  2. Django set default form values
  3. Creating a dynamic choice field
  4. dynamically add field to a form
  5. Django Passing Custom Form Parameters to Formset
  6. How can I build multiple submit buttons django form?
  7. Django: multiple models in one template using forms [closed]
  8. Django reverse lookup of foreign keys
  9. Django ModelForm for Many-to-Many fields
  10. Multiple Models in a single django ModelForm?
  11. Django-Registration & Django-Profile, using your own custom form
  12. Define css class in django Forms
  13. Django formsets: make first required?
  14. How do I add a placeholder on a CharField in Django?
  15. How to create a UserProfile form in Django with first_name, last_name modifications?
  16. Change Django ModelChoiceField to show users’ full names rather than usernames
  17. Django: adding an “Add new” button for a ForeignKey in a ModelForm
  18. Using request.user with Django ModelForm
  19. Overriding the save method in Django ModelForm
  20. What’s the best way to store a phone number in Django models?
  21. How to change the file name of an uploaded file in Django?
  22. Customize/remove Django select box blank option
  23. Django – form.save() is not creating ModelForm
  24. How to set and get session variable in django?
  25. How do I filter values in a Django form using ModelForm?
  26. Change a Django form field to a hidden field
  27. Django form.as_p DateField not showing input type as date
  28. Django – Working with multiple forms
  29. CSRF Token missing or incorrect
  30. Django ModelForm to have a hidden input

Leave a Comment