[Django]-Setting initial Django form field value in the __init__ method

I had that exact same problem and I solved it doing this:

def __init__(self, *args, **kwargs):
    instance = kwargs.get('instance', None)

    kwargs.update(initial={
        # 'field': 'value'
        'km_partida': '1020'
    })

    super(ViagemForm, self).__init__(*args, **kwargs)

    # all other stuff

Try this way:

super(ViagemForm, self).__init__(*args, **kwargs)

if field_value:
    #self.initial[field_name] = field_value
    self.fields[field_name].initial = field_value

I want to mention, although this might not solve your problem, that an ‘initial’ dict kwarg sent to a form appears to get preference over field['field_name'].initial.

class MyView(View):
    form = MyForm(initial={'my_field': 'first_value'})

class MyForm(Form):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields['my_field'].initial = 'second_value'

my_field rendered will have initial set to 'first_value'.

Some options (among others) might be:

Determine second_value in the view before initializing the form:

class MyView(View):
    # determine second_value here
    form = MyForm(initial={'my_field': 'second_value'})

replace first_value with second_value in initial before calling super():

class MyForm(Form):
    def __init__(self, *args, **kwargs):
        # determine second_value here
        if kwargs.get('initial', None):
            kwargs['initial']['my_field'] = 'second_value'
        super().__init__(*args, **kwargs)

Make sure 'first_value' isn’t in kwargs['initial'] before calling super():

class MyForm(Form):
    def __init__(self, *args, **kwargs):
        if kwargs.get('initial', None):
            if kwargs['initial']['my_field']
                del(kwargs['initial']['my_field']
        super().__init__(*args, **kwargs)
        # determine second_value here
        self.fields['my_field'].initial = 'second_value'

I had a similar problem setting the initial value for a radio button called ‘needs_response’ and solved it by inspecting self’s attributes and referencing ‘declared_fields’:

    # views.py
    def review_feedback_or_question(request, template, *args, **kwargs):
        if 'fqid' in kwargs:
            fqid = kwargs['fqid']
        submission = FeedbackQuestion.objects.get(pk=fqid)
        form = FeedbackQuestionResponseForm(submission_type=submission.submission_type)
        # other stuff

    # forms.py
    class FeedbackQuestionResponseForm(forms.Form):
        CHOICES = (('1', 'Yes'), ('2', 'No'))
        response_text = forms.CharField(
            required=False,
            label='',
            widget=forms.Textarea(attrs={'placeholder': 'Enter response...'}))
        needs_response = forms.ChoiceField(choices=CHOICES,
            label='Needs response?',
            widget=forms.RadioSelect())
        def __init__(self, *args, **kwargs):
            if 'submission_type' in kwargs:
                submission_type = kwargs.pop('submission_type')
                if submission_type == 'question':
                    self.declared_fields['needs_response'].initial = 1
                else:
                    self.declared_fields['needs_response'].initial = 2
            super(FeedbackQuestionResponseForm, self).__init__(*args, **kwargs)

This works:

class BarForm(forms.ModelForm):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields['state'] = forms.ChoiceField(
            required=False,
            choices=Foo.ADDRESS_STATE_CHOICES,
            disabled='disabled',
            initial='xyz',
        )

    state = forms.ChoiceField(
        label='State',
        choices=Foo.ADDRESS_STATE_CHOICES,
        initial='foo',
    )

Make initial= "" in the field definition will solve your problem. Both proposed methods are correct you need just to define initial= "" in the field definitoion and the problem is solved