Voting example from tutorial - use of forms API - suggestion

[bradders]

I'm a django newbie working through the tutorials and documentation to get me going for a project.

I built the simple Poll app - very useful introduction. I then wanted to learn the Forms API, and it seemed an obvious learning exercise to implement the voting form using the API. Turned out to be much harder than I expected - perhaps I haven't used the most appropriate technique - but can I suggest you include an implementation (happy for you to use mine) within the "working with forms" introduction to keep people like me sane.

My solution is below. I was using Google App Engine so you'll see use of object keys instead of ids and other limitations of app engine that I'm sure you could easily turn into proper django.

Implement a forms.VotingForm class:

class VotingForm(forms.Form):
    # this needs to be hidden    
    poll_key = forms.CharField(widget=forms.HiddenInput)
    
    # we need to add this choice dynamically at run time
    def __init__(self, vote_choices, *args, **kwargs):
        super(VotingForm, self).__init__(*args, **kwargs)
        
        form_vote_choices = []
        for vote_choice in vote_choices:
            form_vote_choices.append((vote_choice.key(),vote_choice.choice))  
    
        self.fields['choice']= forms.ChoiceField(label='Your vote',
                                   widget=forms.RadioSelect,
                                   choices=form_vote_choices)       

Change the poll.views.poll_detail function to populate the form:

def poll_detail(request, poll_key):
    
    aPoll = Poll.get(poll_key)
    aVotingForm = VotingForm(aPoll.choice_set)
    if aPoll:
        
        return render_to_response('polls/poll_detail.html',
            {'poll':aPoll,'voting_form':aVotingForm})
    else:
     
        raise Http404

And the html:

<form action="/polls/{{ poll.key }}/vote/" method="post">

{{ voting_form.as_p }}
<input type="submit" value="Vote" />

</form>

[Gabriel Hurley]

On the one hand, I agree with bradders about it being a natural next step to try and create a form for the polls app. Unfortunately, the polls app is not designed in a way that making a form for it is simple.

On the other hand, this is a relatively advanced topic, and also somewhat of an uncommon case (in which you're creating a form to select among the items in a reverse relationship), so I don't see it belonging in either the tutorial or the docs/topics/forms overview.

It does seem like some documentation on modifying forms at runtime would be handy, since glancing through all the form docs I don't see any great examples.

I'm not sold on this ticket, but pending a real patch I'm alright with the idea.

[Aymeric Augustin]

Change UI/UX from NULL to False.

[Aymeric Augustin]

Change Easy pickings from NULL to False.

[Tim Graham]

Agreed with Gabriel, if we had a patch it might be worth considering.