Question

I was trying to dynamically generate fields as shown in http://jacobian.org/writing/dynamic-form-generation/. My case slightly differs in that I am looking to use multiplechoicefield that is dynamically created. This is what I came up with…

views.py

def browseget(request):
    success = False
    if request.method == 'POST':
        list_form = ListForm(request.POST)
        if list_form.is_valid():
            success = True
            path = list_form.cleaned_data['path']
            minimum_size = list_form.cleaned_data['minimum_size']
            follow_link = list_form.cleaned_data['follow_link']
            checkboxes = list_form.cleaned_data['checkboxes']
            ....do something
    else:
        list_form = ListForm(name_list)
    ctx = {'success': success, 'list_form': list_form, 'path': path, 'minimum_size': minimum_size}
    return render_to_response('photoget/browseget.html', ctx, context_instance=RequestContext(request))

forms.py

class ListForm(forms.Form):
    path = forms.CharField(required=False)
    minimum_size = forms.ChoiceField(choices=size_choices)
    follow_link = forms.BooleanField(required=False, initial=True)

    def __init__(self, *args, **kwargs):
        name_list = kwargs.pop('name_list', None)
        super(ListForm, self).__init__(*args, **kwargs)
        print 'Received data:', self.data
        if name_list:
            name_choices = [(u, u) for u in name_list]
            self.fields['checkboxes'] = forms.MultipleChoiceField(required=False, label='Select Name(s):', widget=forms.CheckboxSelectMultiple(), choices=name_choices)

    def clean_path(self):
        cd = self.cleaned_data
        path = cd.get('path')
        if path == '': path = None
        return path

    def clean_minimum_size(self):
        cd = self.cleaned_data
        minimum_size = cd.get('minimum_size')
        if minimum_size is None: minimum_size = 0
        return int(minimum_size)

The form generates and displays perfectly… until I post some data. The ‘checkboxes’ field doesn’t show up in list_form.cleaned_data.items() while it shows in self.data. As it is the form breaks with a KeyError exception. So Im asking, how do i access the checkboxes data?

Answer 1

You’re not passing in the name_list parameter when you re-instantiate the form on POST, so the field is not created because if name_list is False.