update form - using formsets - initial values unknown until runtime - django

Question

I'm new to python and Django and have a simple question on how to update f form that has multiple fields of same type: I have been trying to do this with formsets:
I have a simple model to store categories:
class Category(BaseModel):
categoryText = db.StringProperty()
parentCat = db.IntegerProperty()
I want to create a form that would display all available categories in input fields so they could all be edited:
using formsets to display mulitple rows of the same type:
EDIT:
figured it out:
I had to create a list of dictionary items
categories = Category.objects.all()
initialStuff = []
oneFormV={}
for cat in categories:
oneFormV.clear()
oneFormV["categoryText"]=cat.categoryText
oneFormV["parentCat"]=str(cat.parentCat)
oneFormV["catID"]=str(cat.key().id())
initialStuff.append(oneFormV.copy())
def showCategories(request):
if request.POST:
# code to update db
else:
categories = Category.objects.all()
initialStuff = []
for cat in categories:
initialStuff += "'categoryText':u'" + cat.categoryText +"'," + "'parentCat':u'" + str(cat.parentCat) +"'," + "'catID':u'" + str(cat.key().id()) + "'"
initialStuff = initialStuff [:-1] # remove last comma
CategoryFormSet = formset_factory(CategoryForm,extra=categories.count())
formset = CategoryFormSet(initial= initialStuff )
return render_to_response('adminCategories.html', {'formset': formset})
I am having problem with populating the initial data. When I generate in a loop it gives me errors :
class CategoryForm(forms.Form):
categoryText = forms.CharField()
parentCat = forms.CharField()
catID = forms.CharField()
I am assuming I need to store the ID for the fields to update them!
Finally my question:
1) Am I doing this right or is there an easier way to accomplish this?
2) my problem has been passing initial values to a formset with initial values unknown until run time.
3) should I forget about formsets and do this by adding fields to the form with init?
4) what is the correct way of initializing form fields in a formset?
AM

Answer 1

initialStuff must be list of dicts, not list of strings:
for cat in categories:
initialStuff.append( { categoryText: cat.categoryText,
...
}
)
So, don't remove the last comma.
If you use the operation += for list and str you get a list of strings (each str has length 1).
Please view the next: http://docs.djangoproject.com/en/dev/topics/forms/formsets/#using-initial-data-with-a-formset