Django set default form values

Question

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/')

Answer 1

You can use Form.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) 

Answer 2

Other solution: Set initial after creating the form:

form.fields['tank'].initial = 123

Answer 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

Answer 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

Answer 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']

Answer 6

If you want to add initial value and post other value you have to add the following :

or None after request.POST

form = JournalForm(request.POST or None,initial={'tank': 123})

If you want to add files or images also

form = JournalForm(request.POST or None,request.FILES or None,initial={'tank': 123})

Answer 7

I hope this can help you:

form.instance.updatedby = form.cleaned_data['updatedby'] = request.user.id

Answer 8

I also encountered the need to set default values in the form during development. My solution is

initial={"":""}
form=ArticleModel(request.POST)
if form.has_changed():
    data = {i: form.cleaned_data[i] for i in form.changed_data}
    data.update({key: val for key, val in init_praram.items() if key not in form.changed_data})

use form.has_changed ,if form.fields is required you can use this method

Answer 9

How I added the initial to the form: I read @Sergey Golovchenko answer.

So I just added it to the form in if request.method == 'POST':. But that's not where you place it, if you want to see what value it got before posting the form. You need to put it in the form where the else is.

Example here from views.py

def myForm(request):
    kontext = {}

    if request.method == 'POST':
        # You might want to use clean_data instead of initial here. I found something on a stack overflow question, and you add clean data to the Forms.py, if you want to change the post data. https://stackoverflow.com/questions/36711229/django-forms-clean-data
        form = myModelForm(request.POST, initial={'user': request.user})
        if form.is_valid():
            form.save()
            return redirect('/')
    else:
        # you need to put initial here, if you want to see the value before you post it
        form = myModelForm(initial={'user': request.user})
    kontext['form'] = form
    return render(request, 'app1/my_form.html', kontext)