Question

I have a form in my forms.py that looks like this:

from django import forms

class ItemList(forms.Form):
     item_list = forms.ChoiceField()

I need to populate the item_list with some data from the database. When generated in HTML item_list should be something like:

<select title="ItemList">
   <option value="1">Select Item 1</option>
   <option value="2">Select Item 2</option>
</select>

The options values in my select statement will change almost every time since a variable in the query will often change generating new results.

What do I need to put in the view.py and also in my template files to populate the ItemList with values from the database?

Answer 1

Take a look at this example in the Django documentation:

• http://docs.djangoproject.com/en/dev/topics/forms/modelforms/#a-full-example

Basically, you can use the queryset keyword argument on a Field object, to grab rows from your database:

class BookForm(forms.Form):
    authors = forms.ModelMultipleChoiceField(queryset=Author.objects.all())

---

Update

If you need a dynamic model choice field, you can hand over your item id in the constructor of the form and adjust the queryset accordingly:

class ItemForm(forms.Form):

    # here we use a dummy `queryset`, because ModelChoiceField
    # requires some queryset
    item_field = forms.ModelChoiceField(queryset=Item.objects.none())

    def __init__(self, item_id):
        super(ItemForm, self).__init__()
        self.fields['item_field'].queryset = Item.objects.filter(id=item_id)

P.S. I haven’t tested this code and I’m not sure about your exact setup, but I hope the main idea comes across.

Resources:

• http://www.mail-archive.com/[e-mail]/msg48058.html
• http://docs.djangoproject.com/en/dev/ref/forms/fields/#django.forms.ModelChoiceField