Question

I’m building my first form with django, and I’m seeing some behavior that I really did not expect at all. I defined a form class:

class AssignmentFilterForm(forms.Form):
filters = []
filter = forms.ChoiceField()

def __init__(self, *args, **kwargs):
    super(forms.Form, self).__init__(*args, **kwargs)
    self.filters.append(PatientFilter('All'))
    self.filters.append(PatientFilter('Assigned', 'service__isnull', False))
    self.filters.append(PatientFilter('Unassigned', 'service__isnull', True))

    for i, f in enumerate(self.filters):
        self.fields["filter"].choices.append((i, f.name))

When I output this form to a template using:

{{ form.as_p }}

I see the correct choices. However, after refreshing the page, I see the list three times in the select box. Hitting refresh again results in the list showing 10 times in the select box!

Here is my view:

@login_required
def assign_test(request):
pg = PhysicianGroup.objects.get(pk=physician_group)

if request.method == 'POST':
    form = AssignmentFilterForm(request.POST)
    if form.is_valid():
        yes = False
else:
    form = AssignmentFilterForm()
    patients = pg.allPatients().order_by('bed__room__unit', 'bed__room__order', 'bed__order' )

return render_to_response('hospitalists/assign_test.html', RequestContext(request,  {'patients': patients, 'form': form,}))

What am I doing wrong?

Thanks, Pete

Answer 1

I picked up the book Pro Django which answers this question. It’s a great book by the way, and I highly recommend it!

The solution is to make BOTH the choice field and my helper var both instance variables:

class AssignmentFilterForm(forms.Form):
def __init__(self, pg, request = None):
    super(forms.Form, self).__init__(request)
    self.filters = []

    self.filters.append(PatientFilter('All'))
    self.filters.append(PatientFilter('Assigned', 'service__isnull', False))
    self.filters.append(PatientFilter('Unassigned', 'service__isnull', True))
    self.addPhysicians(pg)

    self.fields['filter'] = forms.ChoiceField()
    for i, f in enumerate(self.filters):
        self.fields['filter'].choices.append((i, f.name))

Clearing out the choices works but would surely result in threading issues.