Django FormWizard如何动态更改form_list

Posted 2023-02-24

【中文标题】Django FormWizard如何动态更改form_list

【英文标题】：Django FormWizard how to change the form_list dynamically

【发布时间】：2013-10-04 19:05:13

【问题描述】：

我可以to dynamically call one form related to the data I chose from the step ealier。

但是当我使用done 方法时，我可以看到我的form_list 保持不变。

这就是我所做的：

def get_form_list(request, form_list=None):
    if form_list is None:
        form_list = [ProviderForm, DummyForm, ConsummerForm, DummyForm, \
                 ServicesDescriptionForm]
    return UserServiceWizard.as_view(form_list=form_list)(request)


class UserServiceWizard(SessionWizardView):
    instance = None

    def __init__(self, **kwargs):
        self.form_list = kwargs.pop('form_list')
        return super(UserServiceWizard, self).__init__(**kwargs)

    def get_form_instance(self, step):
        if self.instance is None:
            self.instance = UserService()
        return self.instance

    def get_context_data(self, form, **kwargs):
        data = self.get_cleaned_data_for_step(self.get_prev_step(
                                                    self.steps.current))
        if self.steps.current == '1':
            service_name = str(data['provider']).split('Service')[1]
            form = class_for_name('th_' + service_name.lower() + '.forms',
                                  service_name + 'ProviderForm')
            self.form_list['1'] = form #here my form is correctly change I can see 

        elif self.steps.current == '3':
            service_name = str(data['consummer']).split('Service')[1]
            form = class_for_name('th_' + service_name.lower() + '.forms',
                                  service_name + 'ConsummerForm')
            self.form_list['3'] = form

        context = super(UserServiceWizard, self).get_context_data(form=form,
                                                              **kwargs)
        return context


    def done(self, form_list, **kwargs):
        print self.form_list #here form_list contains ProviderForm, DummyForm, ConsummerForm, DummyForm, ServicesDescriptionForm

在第 0 步，我的 form_list 没问题：

u'0': <class 'django_th.forms.wizard.ProviderForm'>, 
u'1': <class 'django_th.forms.wizard.DummyForm'>, 
u'2': <class 'django_th.forms.wizard.ConsummerForm'>, 
u'3': <class 'django_th.forms.wizard.DummyForm'>, 
u'4': <class 'django_th.forms.base.ServicesDescriptionForm'>

在第 1 步，我的 form_list 没问题：我们可以看到第二个表单是我预期的

u'0': <class 'django_th.forms.wizard.ProviderForm'>, 
u'1': <class 'th_rss.forms.RssProviderForm'>, 
u'2': <class 'django_th.forms.wizard.ConsummerForm'>, 
u'3': <class 'django_th.forms.wizard.DummyForm'>, 
u'4': <class 'django_th.forms.base.ServicesDescriptionForm'>

在第 2 步，我的 form_list 是 ko ；与第 0 步相同：我的第二种形式是返回 DummyForm

u'0': <class 'django_th.forms.wizard.ProviderForm'>, 
u'1': <class 'django_th.forms.wizard.DummyForm'>, 
u'2': <class 'django_th.forms.wizard.ConsummerForm'>,
u'3': <class 'django_th.forms.wizard.DummyForm'>, 
u'4': <class 'django_th.forms.base.ServicesDescriptionForm'>

如何更改 self.form_list 并将我在 get_context_data 中所做的更改保留到向导结束而不是每一步？

编辑 这是与 Rohan 的建议完美配合的完整代码：

def get_form(self, step=None, data=None, files=None):
    """
        change the form instance dynamically from the data we entered
        at the previous step
    """
    if step is None:
        step = self.steps.current

    if step == '1':
        # change the form
        prev_data = self.get_cleaned_data_for_step('0')
        service_name = str(prev_data['provider']).split('Service')[1]
        class_name = 'th_' + service_name.lower() + '.forms'
        form_name = service_name + 'ProviderForm'
        form_class = class_for_name(class_name, form_name)
        form = form_class(data)
    elif step == '3':
        # change the form
        prev_data = self.get_cleaned_data_for_step('2')
        service_name = str(prev_data['consummer']).split('Service')[1]
        class_name = 'th_' + service_name.lower() + '.forms'
        form_name = service_name + 'ConsummerForm'
        form_class = class_for_name(class_name, form_name)
        form = form_class(data)
    else:
        # get the default form
        form = super(UserServiceWizard, self).get_form(step, data, files)
    return form

def done(self, form_list, **kwargs):
    """
        Save info to the DB
        The process is :
        1) get the infos for the Trigger from step 0, 2, 4
        2) save it to TriggerService
        3) get the infos from the "Provider" and "Consummer" services
        at step 1 and 3
        4) save all of them
    """
    # get the datas from the form for TriggerService
    i = 0
    for form in form_list:
        # cleaning
        data = form.cleaned_data
        # get the service we selected at step 0 : provider
        if i == 0:
            trigger_provider = UserService.objects.get(
                name=data['provider'],
                user=self.request.user)
            model_provider = get_service_model('provider', data)
        # get the service we selected at step 2 : consummer
        elif i == 2:
            trigger_consummer = UserService.objects.get(
                name=data['consummer'],
                user=self.request.user)
            model_consummer = get_service_model('consummer', data)
        # get the description we gave for the trigger
        elif i == 4:
            trigger_description = data['description']
        i += 1

    # save the trigger
    trigger = TriggerService(
        provider=trigger_provider, consummer=trigger_consummer,
        user=self.request.user, status=True,
        description=trigger_description)
    trigger.save()

    model_fields = 
    # get the datas from the form for Service related
    # save the related models to provider and consummer
    i = 0
    for form in form_list:
        model_fields = 
        data = form.cleaned_data
        # get the data for the provider service
        if i == 1:
            for field in data:
                model_fields.update(field: data[field])
            model_fields.update('trigger_id': trigger.id, 'status': True)
            model_provider.objects.create(**model_fields)
        # get the data for the consummer service
        elif i == 3:
            for field in data:
                model_fields.update(field: data[field])
            model_fields.update('trigger_id': trigger.id, 'status': True)
            model_consummer.objects.create(**model_fields)
        i += 1

    return HttpResponseRedirect('/')

【参考方案1】：

与其在get_context_data() 中更改表单列表等，我认为更合适的是在您的向导视图中实现get_form() 方法并根据步骤和以前的数据返回不同的表单实例。

类似这样的：

class UserServiceWizard(SessionWizardView):
    instance = None

    def get_form(self, step=None, data=None, files=None):
        if step is None:
            step = self.steps.current

        prev_data = self.get_cleaned_data_for_step(self.get_prev_step(
                                                    self.steps.current))
        if step == '1':
            service_name = str(prev_data['provider']).split('Service')[1]
            form_class = class_for_name('th_' + service_name.lower() + '.forms',
                                  service_name + 'ProviderForm')
            form = form_class(data)
        elif step == '3':
            service_name = str(prev_data['consummer']).split('Service')[1]
            form_class = class_for_name('th_' + service_name.lower() + '.forms',
                                  service_name + 'ConsummerForm')
            form = form_class(data)
        else:
            form = super(UserServiceWizard, self).get_form(step, data, files)

        return form

这里的技巧是不要更改表单列表的长度（您已经正确完成了），而只是更改表单实例。为此，Django 提供了覆盖get_form() 方法的方法。 Django 将尊重此方法并始终使用它来获取该方法的表单实例。

【讨论】：

为您答复。我试试看。我也用 get_form 做了一些测试，但没有成功。事实上，我用表单向导的每个功能测试了很多解决方案，结果我什么也没看到。

所以我放弃了我的 get_context_data，我的第一个测试在 step1 没有返回任何数据； prev_data 是空的，所以 prev_data['provider'] 失败，'NoneType' object has no attribute '__getitem__'

是的！我几乎达到了目标。我会尽快确认！

@FoxMaSk，不要认为这个错误是相关的。如果您仍然收到该错误，也许您可​​以发布您的实际代码。

我确认您的回答并感谢您的帮助。现在我还有其他问题，但这里的主要问题已经解决了！

【参考方案2】：

我不确定这是否是您正在寻找的解决方案，但如果您在 process_step 而不是在 get_context_data 中修改 form_list 它应该可以工作。您必须更改您的代码，因为 process_step 在提交表单后执行。

根据 Django doc https://docs.djangoproject.com/en/1.5/ref/contrib/formtools/form-wizard/ process_step 是“修改向导内部状态的钩子”，至少对于 self.kwargs vars（实际上你的 form_list 在 self.kwargs["form_list"]）我已经测试过了get_context_data 中的所有修改都将被忽略，因此我认为 self.form_list 的行为方式应该相同。

【讨论】：

我将 pdb 放入循环中以跟踪向导所遵循的路径。所以第一个是 __init__of course ;) 其次是 get_context_data，最后是 process_step，除了最后一个步骤，路径变为__init__，然后是process_step，然后是done。但在我这边，让我即时更改表单的唯一功能不是process_step，而是get_context_data。 process_step 没有注意到...