Question or problem about Python programming:
I have a Model as follows:
class TankJournal(models.Model): user = models.ForeignKey(User) tank = models.ForeignKey(TankProfile) ts = models.IntegerField(max_length=15) title = models.CharField(max_length=50) body = models.TextField()
I also have a model form for the above model as follows:
class JournalForm(ModelForm): tank = forms.IntegerField(widget=forms.HiddenInput()) class Meta: model = TankJournal exclude = ('user','ts')
I want to know how to set the default value for that tank hidden field. Here is my function to show/save the form so far:
def addJournal(request, id=0): if not request.user.is_authenticated(): return HttpResponseRedirect('/') # checking if they own the tank from django.contrib.auth.models import User user = User.objects.get(pk=request.session['id']) if request.method == 'POST': form = JournalForm(request.POST) if form.is_valid(): obj = form.save(commit=False) # setting the user and ts from time import time obj.ts = int(time()) obj.user = user obj.tank = TankProfile.objects.get(pk=form.cleaned_data['tank_id']) # saving the test obj.save() else: form = JournalForm() try: tank = TankProfile.objects.get(user=user, id=id) except TankProfile.DoesNotExist: return HttpResponseRedirect('/error/')
How to solve the problem:
Solution 1:
You can use initial which is explained here
You have two options either populate the value when calling form constructor:
form = JournalForm(initial={'tank': 123})
or set the value in the form definition:
tank = forms.IntegerField(widget=forms.HiddenInput(), initial=123)
Solution 2:
Other solution: Set initial after creating the form:
form.fields['tank'].initial = 123
Solution 3:
If you are creating modelform from POST values initial can be assigned this way:
form = SomeModelForm(request.POST, initial={"option": "10"})
https://docs.djangoproject.com/en/1.10/topics/forms/modelforms/#providing-initial-values
Solution 4:
I had this other solution (I’m posting it in case someone else as me is using the following method from the model):
class onlyUserIsActiveField(forms.ModelForm): def __init__(self, *args, **kwargs): super(onlyUserIsActiveField, self).__init__(*args, **kwargs) self.fields['is_active'].initial = False class Meta: model = User fields = ['is_active'] labels = {'is_active': 'Is Active'} widgets = { 'is_active': forms.CheckboxInput( attrs={ 'class': 'form-control bootstrap-switch', 'data-size': 'mini', 'data-on-color': 'success', 'data-on-text': 'Active', 'data-off-color': 'danger', 'data-off-text': 'Inactive', 'name': 'is_active', }) }
The initial is definded on the __init__
function as self.fields['is_active'].initial = False
Solution 5:
As explained in Django docs, initial
is not default
.
-
The initial value of a field is intended to be displayed in an HTML . But if the user delete this value, and finally send back a blank value for this field, the
initial
value is lost. So you do not obtain what is expected by a default behaviour. -
The default behaviour is : the value that validation process will take if
data
argument do not contain any value for the field.
To implement that, a straightforward way is to combine initial
and clean_<field>()
:
class JournalForm(ModelForm): tank = forms.IntegerField(widget=forms.HiddenInput(), initial=123) (...) def clean_tank(self): if not self['tank'].html_name in self.data: return self.fields['tank'].initial return self.cleaned_data['tank']