Disabled field causes form validation error in Django

Question

There is a case where I need to reuse the same ModelForm (The name's EngagementForm) in several cases, but wanted to disable some of the fields depends on the case. So I applied disabled inside my forms.py:

# Override Field Initialisation, used for disabling fields
def __init__(self, *args, **kwargs):
    schedule_check = kwargs.pop('schedule', False)
    super(EngagementForm, self).__init__(*args, **kwargs)

    # If schedule argument set to True, disable the following fields
    if schedule_check:
        fields = (
            'project_code',
            'project_name',
            'user_credential',
        )

        for i in fields:
            self.fields[i].disabled = True
            self.fields[i].required = False

However, Django throws validation error when I perform submit. The form.is_valid() returns False, and while inspecting errors using Pdb I saw this:

(Pdb) form.errors
{'project_code': ['This field is required.'],
 'project_name': ['This field is required.'],
 'user_credential': ['This field is required.']}

Check for their values, seems like disabled took away their values (or I might wrong here):

(Pdb) form['project_code'].value()
(Pdb)

I've tried few solutions found online (including feeding in initial values for each fields) yet none of these could fix the issue here.

FYI, this is the code in views.py:

def schedule_form(request, pk):
engagement = get_object_or_404(Engagement, pk=pk)
if request.method == "GET":
    context = {
        'title': "Schedule Task",
        'form': EngagementForm(
            instance=engagement,
            schedule=True,
        ),
    }

    return render(request, 'forms/engagement_form.html', context)

else:  # POST request
    form = EngagementForm(request.POST, instance=engagement)

    # Django thinks the form is invalid #
    if form.is_valid():
        form.save(update_fields=['schedule_date'])
        return redirect('index')

    else:
        # Shows error message
        # Django executed this block upon submit #

Much appreciated if I can get help from you guys, at least I should know what did I miss here.

score 2 · Answer 1 · answered Apr 07 '20 at 06:30

The solution was mentioned in here. Since of the way HTML handles the POST method, all disabled fields won't passed to the backend, causes form validation error.

Solution #1 solved my issue, straightforward yet not elegant codewise. However, solution #2 is more elegant IMO yet did not solve the issue.

Disabled field causes form validation error in Django

1 Answers1