Django Forms: pass parameter to form

You should define the __init__ method of your form, like that:

class StylesForm(forms.Form):
    def __init__(self,*args,**kwargs):
        self.site_id = kwargs.pop('site_id')
        super(StylesForm,self).__init__(*args,**kwargs)

of course you cannot access self.site_id until the object has been created, so the line:

     height = forms.CharField(widget=forms.TextInput(attrs={'size':site_id}))

makes no sense. You have to add the attribute to the widget after the form has been created. Try something like this:

class StylesForm(forms.Form):
    def __init__(self,*args,**kwargs):
        self.site_id = kwargs.pop('site_id')
        super(StylesForm,self).__init__(*args,**kwargs)
        self.fields['height'].widget = forms.TextInput(attrs={'size':site_id})

    height = forms.CharField()

(not tested)

This is what worked for me. I was trying to make a custom form . This field in the model is a charfield but I wanted a choice field generated dynamically .

The Form:

class AddRatingForRound(forms.ModelForm):

    def __init__(self, round_list, *args, **kwargs):
        super(AddRatingForRound, self).__init__(*args, **kwargs)
        self.fields['name'] = forms.ChoiceField(choices=tuple([(name, name) for name in round_list]))

    class Meta:
        model = models.RatingSheet
        fields = ('name', )

The Views:

    interview = Interview.objects.get(pk=interview_pk)
    all_rounds = interview.round_set.order_by('created_at')
    all_round_names = [rnd.name for rnd in all_rounds]
    form = forms.AddRatingForRound(all_round_names)
    return render(request, 'add_rating.html', {'form': form, 'interview': interview, 'rounds': all_rounds})

The Template:

<form method="post">
    {% csrf_token %}
    {% if interview %}
     {{ interview }}
    {% if rounds %}
        {{ form.as_p }}
        <input type="submit" value="Submit" />
    {% else %}
        <h3>No rounds found</h3>
    {% endif %}
</form>