Question

I have the following models:

# Group for Key/Value pairs
class Group(models.Model):
    name = models.TextField(unique=True)

    def __unicode__(self):
        return self.name


    class Meta:
        verbose_name = 'Group'
        verbose_name_plural = 'Groups'

# Key is the key/name for a Value
class Key(models.Model):
    name = models.TextField(unique=True)

    def __unicode__(self):
        return self.name


    class Meta:
        verbose_name = 'Key'
        verbose_name_plural = 'Keys'

# Value is the value/content of a key
class Value(models.Model):
    value = models.TextField()

    def __unicode__(self):
        return '%s' % self.value


    class Meta:
        verbose_name = 'Value'
        verbose_name_plural = 'Values'

class Key_Value(models.Model):
    group = models.ForeignKey(Group)
    key = models.ForeignKey(Key)
    value = models.ForeignKey(Value)

    def __unicode__(self):
        return '%s = %s' % (self.key.name, self.value.value)


    class Meta:
        verbose_name = 'Key/Value Paar'
        verbose_name_plural = 'Key/Value Paare'


Now I pass the form to the template:
def exampleview(request):
    key_value_form = Key_Value_Form(request.POST)
    return render_to_response(
            'edit.html', {
                'key_value_form': key_value_form,
                })

Now lets look at possible data

KEY/VALUE PARIRS:
key = TEST 1
value = TEST 1
group = TESTGROUP 1

key = TEST 2
value = TEST 2
group = TESTGROUP 2

Now I changed the default widgets for the Key/Value Table entries to select widgets.

Here’s what I want to do:

SELECT GROUP [+] [-]
   --> [Now choose Key/Value pair belonging to group] [+] [-]

at the start you always get two selects one for the group and one for the key/value pair.
if you press the + at the GROUP a new group select button should appear along with a KEY/Value Pair select, if you press the + at the Key/Value select a new key/value select box should appear.

I have two problems:

ONE: I don’t know how the check in the template should look like and
TWO: How I can implement those + – Buttons

Any Help is appreciated. It would be cool if this would be possible without javascript but I don’t have very high hopes in that direction

Answer 1

You need to build the form on the fly. Suppose you had a definition of a group form built in a dictionary from a view in your view handler (containing group model foreign keys and number of actual keys in them):

# note that the dictionary d shown here is just an example
# yours should have actual group foreign keys based on Group model
d = { 'first' : 5,  'second' : 3, 'third' : 2 }

def make_groupkeys_form(descriptor):
    groups = { 'select': '', 'keypairs' : [] }
    fields = { 'groups' : groups }

    for group, numkeys in descriptor.values():
        groupchoices = # find out what choices you need to offer for group widget
        groups['select'] = forms.SelectField(choices=groupchoices)
        for i in range(numkeys):
             keyvalchoices = # find out what choices you need to offer for keyval widget per group
             groups['keypairs'].append(forms.SelectField(choices=keyvalchoices))

    # now you have enough SelectFields for all your groups and keyval pairs
    return type('Key_Value_Form', (forms.BaseForm,), { 'base_fields': fields })

# from view handler
def exampleview(request):
    # determine from request how many groups you want and how many keyval widgets per group, for example here I will use the above predefined d

    key_value_form = make_groupkeys_form(d)
    return render_to_response(
            'edit.html', {
                'key_value_form': key_value_form,
                })

Note that you can (and should) rewrite a class Key_Value_Form to inherit from forms.BaseForm and put the make_groupkeys_form(descriptor) code in its __init__(request, descriptor) member. You will also need to do write your own is_valid() to enumerate through select fields and make sure the choices are correct when the user submits the form and override clean() to attempt to validate individual user’s choices.

Finally, consider going through this dynamic forms read. It will guide you step by step in how to create dynamic forms in django.