如何使用 WizardView (Django 1.4) 创建动态表单？

Question

完整的问题陈述涉及多个步骤，然而，它的核心是这个简单的场景：

假设我有两种形式

from django import forms

class Form1(forms.Form):
    char_field1=forms.CharField(label='field 1')
    char_field2=forms.CharField(label='field 2')
    char_field3=forms.CharField(label='field 3')

class Form2(forms.Form):
    choice_field = forms.ChoiceField()

现在使用django.contrib.formtools.wizard.views.WizardView 或其子类，我想用用户在char_field1 - char_field3 中填写的选项填充choice_field。

当要返回 Form2 时，我尝试覆盖 get_form 并填充选择字段。它确实在呈现的表单中显示了选项，但表单在提交时没有验证。

我的直觉告诉我这应该是可能的，“如何”是我无法弄清楚的。

Answer 1

迟到总比没有好...我自己最近也遇到过这种情况，不得不重写表单的（第二步）init 方法，并将一个初始关键字从 WizardView 传递给表单。从那里我可以有条件地设置表单字段的选项。

我自己的实现-

views.py

class QuoteWizard(SessionWizardView):
    form_list = [QQFormProductLine, QQProduct, QQProductFluidProperties]
    ...
    def get_form_initial(self, step):
        #pass variables to forms from here
        initial = self.initial_dict.get(step, {})
        if int(step) > 0:
            self.temperature_units, self.measurement_format = self.get_measurement_units()
            initial.update({'measurement_format': self.measurement_format})
        return initial

forms.py

class QQProduct(forms.ModelForm):
    ...
    def __init__(self, *args, **kwargs):
        super(QQProduct, self).__init__(*args, **kwargs)
        units = None 

        if 'initial'in kwargs:
            initial = kwargs.pop('initial')
            if 'measurement_format' in initial:
                units = initial.pop('measurement_format')

        flow_choices = []
        if units == 'imperial':
            flow_units = qq_models.FlowRateUnits()
            flow_units = flow_units.imperial()
        elif units == 'metric':
            flow_units = qq_models.FlowRateUnits()
            flow_units = flow_units.metric()

        for i in flow_units:
            flow_choices.append((i, qq_models.FlowRateUnits.get(i)))
        if len(flow_choices) > 0:
            self.fields['flow_rate_format'].widget.choices = flow_choices

总而言之，get_form_initial 是一个 WizardView 方法，它将初始关键字传递给表单以执行一个步骤。在我的 self.get_measurement_units() 方法中，我调用 self.get_cleaned_data_for_step('0') 并根据第一步中的用户输入，更改第二步表单中选择字段中显示的选项。

Answer 2

你可以这样做：

views.py：

from django.contrib.formtools.wizard.views import CookieWizardView

class ChoiceWizardView(CookieWizardView):
    def done(self, form_list, **kwargs):
        pass

    def get_form(self, step=None, data=None, files=None):
        form = super(ChoiceWizardView, self).get_form(step, data, files)
        if 'choice_field' in form.fields:
            form1_cleaned_data = self.get_cleaned_data_for_step('0')
            if form1_cleaned_data:
                form.fields['choice_field'].choices = [item for item in form1_cleaned_data.items()]
        return form

urls.py:

from app.forms import Form1, Form2
from app.views import ChoiceWizardView

urlpatterns = patterns('',
    (r'^my_wizard/$', ChoiceWizardView.as_view([Form1, Form2])),
)

它会起作用的。但也许你选择了错误的应用架构？