为隐藏的 ModelForm 字段 Django 设置默认值

Question

I want to pass an initial value for HiddenInput form field in Meta class of ModelForm object. If the field is not hidden, eg as:

class Meta:
    model = SomeModel
    fields = ['some_id', 'some_amount',]

and I pass initial values via kwargs to this form constructor, then initial values are set to these fields correctly.

But when I try to hide one field (but I still need it to be set up to initial value from kwargs ), as eg:

class Meta:
    model = SomeModel
    widgets = {'ord_id': forms.HiddenInput(),}
    fields = ['some_id', 'some_amount',]

Then 'ord_id' is not set up to initial value from kwargs and I get the following error when trying to submit such form:

(Hidden field ord_id) Select a valid choice. That choice is not one of the available choices

So is there any way to pass an initial value to the Hidden form field correctly?

Answer 1

You can set defaults value to form fields in two ways.

first method is by passing default values while on initializing the form in your view.py ie

from forms import ExampleForm

INITIAL_DATA = {'ord_id': 'some_id'}

def my_view(request):
    ...

    if request.method == 'GET':
        form = ExampleForm(initial=INITIAL_DATA)
    if request.method == 'POST':
        form = ExampleForm(request.POST)
    ...

Second is by overriding the form __init__ method ie

class ExampleForm(forms.ModelForm):

def __init__(self, *args, **kwargs):
    """If no initial data, provide some defaults."""
    initial = kwargs.get('initial', {})
    initial['ord_id'] = 'ord_id'
    kwargs['initial'] = initial
    super(ExampleForm, self).__init__(*args, **kwargs)

Answer 2

If you've verified with the inspection tool that your select element really does have the correct option selected, the problem may be that your field is disabled somehow instead of just hidden. I've seen similar error messages from attempting to submit disabled fields. If that's not the case, I may have an alternative solution for designating your fields as hidden.

If you are using django templates you can use widget tweaks to modify form fields in the template, which allows you to do things like add classes and styles or change values. So you can pass the initial arguments to your form as you have already and hide them using template tags. Hope this works for you!

{% for field in form %}
    {% if field == form.hidden_field_name %}
        {% render_field field hidden='True' id='hidden-field' class='hidden-field-class' %}
    {% endif %}
{% endfor %}