Question

I have a form that seems to never validate. The form is just three drop-down boxes. When the form is rendered, all of the boxes have values populated and the first is selected, so no matter what, the user cannot submit bad values, yet form.is_valid() always returns false. Please help!

The form

CLUSTER_TYPES = (
    ('ST', 'State'),
    ('CNT', 'County'),
    ('FCD', 'Congressional District'),
    ('GCC', 'Circle Clustering'),
);

MAP_VIEWS = (
    ('1', 'Single Map'),
    ('2', 'Two Maps'),
    ('4', 'Four Maps'),
);
class ViewDataForm (forms.Form):
    def __init__ (self, sets = None, *args, **kwargs):
        sets = kwargs.pop ('data_sets')
        super (ViewDataForm, self).__init__ (*args, **kwargs)

        processed_sets = []
        for ds in sets:
            processed_sets.append ((ds.id, ds.name))

        self.fields['data_sets'] = forms.ChoiceField (label='Data Set', choices = processed_sets)
        self.fields['clustering'] = forms.ChoiceField (label = 'Clustering',
                                                       choices = CLUSTER_TYPES)
        self.fields['map_view'] = forms.ChoiceField (label = 'Map View', choices = MAP_VIEWS)

The view

def main_view (request):
    # We will get a list of the data sets for this user
    sets = DataSet.objects.filter (owner = request.user)

    # Create the GeoJSON string object to potentially populate
    json = ''

    # Get a default map view
    mapView = MapView.objects.filter (state = 'Ohio', mapCount = 1)
    mapView = mapView[0]

    # Act based on the request type
    if request.method == 'POST':
        form = ViewDataForm (request.POST, request.FILES, data_sets = sets)
            v = form.is_valid ()
        if form.is_valid ():
            # Get the data set
            ds = DataSet.objects.filter (id = int (form.cleaned_data['data_set']))
            ds = ds[0]

            # Get the county data point classifications
            qs_county = DataPointClassification.objects.filter (dataset = ds, 
                                                                division = form.cleaned_data['clustering'])

            # Build the GeoJSON object (a feature collection)
            json = ''
            json += '{"type": "FeatureCollection", "features": ['
            index = 0
            for county in qs_county:
                if index > 0:
                    json += ','
                json += '{"type": "feature", "geometry" : '
                json += county.boundary.geom_poly.geojson
                json += ', "properties": {"aggData": "' + str (county.aggData) + '"}'
                json += '}'
                index += 1
            json += ']}'

            mapView = MapView.objects.filter (state = 'Ohio', mapCount = 1)
            mapView = mv[0]
    else:
        form = ViewDataForm (data_sets = sets)

    # Render the response
    c = RequestContext (request, 
                        {
                            'form': form, 
                            'mapView_longitude': mapView.centerLongitude,
                            'mapView_latitude': mapView.centerLatitude,
                            'mapView_zoomLevel': mapView.zoomLevel,
                            'geojson': json,
                            'valid_was_it': v
                        })
    return render_to_response ('main.html', c)

Answer 1

You have overridden the signature of the form’s __init__ method so that the first positional parameter is sets. However, when you instantiate it, you pass request.POST as the first positional argument – so the form never gets any data, so doesn’t validate.

Don’t change the signature of __init__. In fact, you have everything set up correctly so you don’t need to: just remove the sets=None from the method definition, and it should all work.