[Django]-Django set default form values

Other solution: Set initial after creating the form:

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

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

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

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']

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})

I hope this can help you:

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

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

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)

Posting another solution i came up with:

template.html:

<form id="myForm" method="post">
{% csrf_token %}
{{ form.media }}
{{ form.well_id.label_tag }}
{{ form.well_id }}
{{ form.tube_id.label_tag }}
{{ form.tube_id }}
<button type="submit" >Run Analysis</button>
</form>

<script type="text/javascript">

    $(document).ready(function() {
        $("#id_well_id").select2();
        $("#id_tube_id").select2();
        
        {% if request.method == 'GET' %} // Because id_tube_id is a 'required' form field, we need to initialize a null parameter to show the placeholder.
        $("#id_tube_id").val(null);
        $("#id_tube_id").trigger('change');
        {% endif %}
    });
</script>

The reasoning behind using this method and not the pure python based methods posted above was that I had set the tube_id field to be a required form field but not the well_id field. Apparently, if you assign a field to be required, it is being prefilled with the first value in your list of choices, unless specified otherwise by an initial value.
But in my case, i didn’t want an initial value – i just wanted the initial value to be None. Django can assign a choice as an initial value only if it allready exists in your list of choices, so if you would assign None as an initial value, it would just show the first item on the list.

The solution is therefore to assign an initial value through javascript (in my case, i needed it to happen only if request.method == ‘GET’).