Question

I’d like to create a form that when viewed, the user’s favorite fruits are queried from the database and displayed as follows:

<select size="4"> 
<option selected>Apples</option>
<option>Bananas</option> 
<option>Oranges</option>
<option>Watermelon</option> 
</select>

The view that uses the form will:

1. Get the user object.
2. Query the database for the user’s favorite fruits. (Each is a separate object of the Fruit model.)
3. Load the form with the fruit choices collected in (2).

I was considering using the ChoiceField, but it looks like you cannot load the list of choices into the form dynamically, at least in a straightforward manner. Am I better off skipping the form and generating the code directly at the template? Or is there a way to load the form’s ChoiceField with the user items at the view?

Also, are there any general rules of thumb that dictate where it’s easier to build a form using the django form fields vs generating the form code at the template?

Answer 1

I found the answer in this stack overflow topic. The trick is to override the form __init__() so that it accepts a new keyword argument, which in this case is the user.

views.py snippet

context = RequestContext(request)
user = User.objects.get(username=context['user'])
form = forms.FruitForm(user=user)

forms.py snippet

from django import forms

class FruitForm(forms.Form):
    fruits = forms.ModelChoiceField(queryset=Fruit.objects.all())

    def __init__(self, *args, **kwargs):
        user = kwargs.pop('user', None)
        super(FruitForm, self).__init__(*args, **kwargs)
        if user:
            self.fields['fruits'].queryset = Fruit.objects.filter(user=user)