Hi,
Your case is complicated enough that I'd actually recommend not using
formsets here and processing a list of plain ModelForms yourself in the
view. I bet formsets will ending out getting in your way.
Here's a some messy code:
class EntryForm(forms.ModelForm):
race_number = Entry._meta.get_field('race_number').formfield(required=
False)
class Meta:
model = Entry
fields = ['race_number']
def the_view(request, athlete_id):
athlete = get_object_or_404(Athlete, id=athlete_id)
existing = {e.category_id: e for e in athlete.entry_set.all()}
entries = []
for category in Category.objects.order_by('particular'):
entries.append(existing.get(category.pk, Entry(athlete=athlete,
category=category)))
if request.method = 'POST':
forms = [EntryForm(request.POST, instance=e, prefix=e.category.pk)
for e in entries]
if all([f.is_valid() for f in forms]): # be sure to call
is_valid() on every form
for entry in entries:
if entry.race_number:
entry.save()
if entry.pk and not entry.race_number:
entry.delete()
else:
forms = [EntryForm(instance=e, prefix=e.category.pk) for e in
entries]
return render(request, 'template.html', {'athlete': athlete, 'forms':
forms})
{% for form in forms %}
Category: {{ form.instance.category }}
{{ form }}
{% endfor %}
Collin
On Monday, December 29, 2014 6:07:19 PM UTC-5, Richard Brockie wrote:
>
> Hi,
>
> I have the following pseudo model that I will use as the basis of a
> modelformset:
>
> class Entry:
> athlete = ForeignKey(athlete)
> category = ForeignKey(category)
> race_number = IntegerField
>
> I have a page that displays each athlete's details so the choice of
> athlete has already been made. I want to add a formset that allows a user
> to specify a race_number for each of the possible categories available.
>
> An obvious way would be for there to be one Entry for each
> athlete/category, but in practise this will result in a large entry table
> that is only ~10% actual data, with the rest being superfluous rows. I'd
> prefer to avoid this.
>
> Let's assume that an athlete is already entered in 2 categories out of a
> possible 10. The queryset will return the 2 existing entries, and I can use
> extra=8 to add in the other possibilities. However, I am not yet done. I
> want to do the following and would like advice on how to accomplish this:
>
> 1. The category for each the 8 possible new entries needs to be
> assigned before displaying the form - I already know what they are and
> want
> to display these categories to the user, leaving the race_number as the
> only input field.
> 2. The categories have a particular (chronological) order that I want
> respected in displaying the forms to the user, so the 2 existing and 8
> possible new categories need to be interspersed to follow the correct
> order.
> 3. When it comes time to save the formset, I want only those
> categories that have been changed by having a race_number assigned or
> removed to be saved. I want the entries where the race_number has been
> removed to remain in the entry table. I think I need a way to detect and
> remove the forms that have not been changed by the user before saving the
> formset.
>
> Any pointers as to how to do this?
>
> Thanks!
> R.
>
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