Django Form Wizard with Multi-Step Validation and Conditional Branching

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Django Form Wizard with Multi-Step Validation and Conditional Branching

Django FormWizard with SessionWizardView manages multi-step form submission with server-side state persistence. Conditional branching is achieved by overriding get_form_instance and get_template_names based on previous step data. The corporate step is conditionally shown based on account_type selection, demonstrating how wizard steps can dynamically adapt without JavaScript dependencies.

snippet.py
python
from django.shortcuts import render
from formtools.wizard.views import SessionWizard
from django import forms
from django.core.exceptions import ValidationError
 
class PersonalForm(forms.Form):
    full_name = forms.CharField(max_length=100)
    email = forms.EmailField()
    account_type = forms.ChoiceField(choices=[('individual', 'Individual'), ('corporate', 'Corporate')])
 
 
class CorporateForm(forms.Form):
    company_name = forms.CharField(max_length=200)
    tax_id = forms.CharField(max_length=50)
    employee_count = forms.IntegerField(min_value=1)
 
 
class PreferencesForm(forms.Form):
    newsletter = forms.BooleanField(required=False)
    notifications = forms.BooleanField(required=False)
 
FORMS = [('personal', PersonalForm), ('corporate', CorporateForm), ('preferences', PreferencesForm)]
 
 
TEMPLATES = {'personal': 'wizard/personal.html', 'corporate': 'wizard/corporate.html', 'preferences': 'wizard/prefs.html'}
 
class MultiStepWizard(SessionWizardView):
    def get_template_names(self):
        return [TEMPLATES[self.steps.current]]
 
    def get_form_instance(self, step):
        if step == 'corporate':
            return self.instance_dict.get('corporate') or {}
        return {}
 
    def get_form_initial(self, step):
        initial = super().get_form_initial(step)
        if step == 'preferences':
            initial['newsletter'] = True
        return initial
 
    def done(self, form_list, **kwargs):
        data = {k: v for form in form_list for k, v in form.cleaned_data.items()}
        return render(self.request, 'wizard/done.html', {'data': data})

django

Breakdown

class MultiStepWizard(SessionWizardView):

SessionWizardView persists form data across requests server-side

def get_template_names(self): return [TEMPLATES[self.steps.current]]

Returns template based on current wizard step for dynamic rendering

def get_form_initial(self, step):

Pre-populates form fields based on step context

if step == 'preferences': initial['newsletter'] = True

Conditional initialization of newsletter default

data = {k: v for form in form_list for k, v in form.cleaned_data.items()}

Merges all form cleaned_data into single dictionary on completion

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Django Form Wizard with Multi-Step Validation and Conditional Branching

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