Django, how to set value in forms.ModelForm - django

Question

I have a question for you. I have the following Model:
class Centro_di_costo(models.Model):
centro_di_costo = models.CharField('Centro di costo', max_length=30)
def __str__(self):
return self.centro_di_costo
class AltriCosti(models.Model):
STATUS_CHOICES= [
('VARIABILE', 'VARIABILE'),
('FISSO', 'FISSO'),
]
centro_di_costo = models.ForeignKey(Centro_di_costo)
sub_centro_di_costo = models.CharField('Categoria', max_length=30)
status = models.CharField(choices=STATUS_CHOICES)
price=models.DecimalField()
quantity=models.IntegerField()
I use it in a lot of view, but in one of them I wanna set the value without passing from the POST request.
So I have tried to set the ModelForm in the following manner:
class ModCollaboratori(forms.ModelForm):
class Meta:
model = AltriCosti
fields = "__all__"
def __init__(self, *args, **kwargs):
super(ModCollaboratori, self).__init__(*args, **kwargs)
self.helper = FormHelper()
self.helper.form_show_labels = False
self.fields['centro_di_costo'].value= "Servizi di Produzione"
self.fields['sub_centro_di_costo'].value = "Collaboratori esterni"
self.fields['status'].value = "VARIABILE"
But It does not work. How could I fix the code to work?

Answer 1

You can exclude fields from your form:
class ModCollaboratori(forms.ModelForm):
class Meta:
model = AltriCosti
exclude = ['centro_di_costo', 'sub_centro_di_costo', 'status']
Then in your view you can "inject" value for these fields:
def some_view(request):
if request.method == 'POST':
form = ModCollaboratori(request.POST, request.FILES)
if form.is_valid():
form.instance.sub_centro_di_costo = 'Collaboratori esterni'
form.instance.status = 'VARIABILE'
form.instance.centro_di_costo = Centro_di_costo.objects.get_or_create(
centro_di_costo='Servizi di Produzione'
)[0]
form.save()
return redirect('name-of-some-view')
else:
form = ModCollaboratori()
return render(request, 'some_template.html', {'form': form})

Answer 2

for your code
self.fields['status'].value = "VARIABLE"
to make it work change to
self.instance.status = "VARIABLE"
Result:
Status: VARIABLE

Answer 3

basically ModelForm.__init__() will populate instance values into form.
but if we add extra field to this form, we will need to populate it by ourself in kwargs["initial"],
because this field not include in the model.
class SomeForm(forms.ModelForm):
custom_field = forms.CharField()
def __init__(self, *args, **kwargs):
kwargs["initial"]["custom_field"] = "xxxxx"
super().__init__(*args, **kwargs)