django inline formsets with a complex model for the nested form

Question

Say I have django model that looks something like this:

class Order(models.Model):
 number = models...
 date = models...

class OrderLine(models.Model):
 # O         


        

Answer 1

This sounds very similar to the approach talked about at help http://yergler.net/blog/2009/09/27/nested-formsets-with-django/ where Nathan writes about how he catered for "a multi-level data model; an example of this kind of model would be modeling City Blocks, where each Block has one or more Buildings, and each Building has one or more Tenants."

Some more explanations can aslo be found here Django Forms Newbie Question

Answer 2

I solved problem with http://yergler.net/blog/2009/09/27/nested-formsets-with-django/. Pleas use the following correction in forms.py file:

        instance=None
            pk_value = hash(form.prefix)

+       correct_data = None
+       if (self.data):
+           correct_data = self.data;
        # store the formset in the .nested property
        form.nested = [
-           TenantFormset(data=self.data,
+           TenantFormset(data=correct_data,
                            instance = instance,

Just working on Django 1.4.1 very well.

Answer 3

Some minor changes were needed to make Nathan's code at http://yergler.net/blog/2009/09/27/nested-formsets-with-django/ work in Django 1.3. The line below causes a ManagementForm Error.

TenantFormset = inlineformset_factory(models.Building, models.Tenant, extra=1)

Usings the modelformset_factory and manually defining the queryset seems to work, but I have not implemented the ability to add extras.

TenantFormset = modelformset_factory(models.Tenant, extra=0)

form.nested = [
        TenantFormset(
                        queryset = Tenant.objects.filter(building = pk_value),
                        prefix = 'value_%s' % pk_value
                        )
                    ]

I also had to manually pass data to the sub-sub-forms in the is_valid method:

def is_valid(self):
result = super(BaseProtocolEventFormSet, self).is_valid()

for form in self.forms:
    if hasattr(form, 'nested'):
        for n in form.nested:
            n.data = form.data
            if form.is_bound:
                n.is_bound = True
            for nform in n:
                nform.data = form.data
                if form.is_bound:
                    nform.is_bound = True
            # make sure each nested formset is valid as well
            result = result and n.is_valid()
return result

EDIT:

New instances can be created using jQuery. See this question: