Question

我希望为用户提供基于现有出版物创建新出版物的可能性。为此，我希望他们单击指向“basedview”的链接，该链接包含他们希望新项目所基于的出版物的ID。包含n：n关系的两个表单集。

应该打开一个预填充表单，其中所有字段都是prefield，其中包含来自它所基于的出版物的数据。一旦用户根据需要进行了更改，它就应该为该字段集保存一个新的出版物和新的关系 - 后者是它的难点部分。

所以我的问题是 - 如何从数据库中加载所有相应的表单集，然后删除所有的pk，但仍然保持与发布项的关系？

现在，在get方法中就是这样：

        self.object = None
        try:
            self.object = KombiPublikation.objects.get(pk=self.kwargs['pk'])
        except ObjectDoesNotExist:
            raise Http404("Keinen Output unter dieser PubID gefunden.")

        form = KombiPublikationForm(instance=self.object)
        pubspr_formset = KombiPublikationSpracheFormset(instance=self.object)
        pubpers_formset = KombiPublikationPersonFormset(instance=self.object)

但这最终只是对现有出版物的编辑。我不知何故必须在之后删除pk 我填充了formset或者找到一种方法以不同的方式填充formset。任何想法？

非常感谢！

这里有完整的代码摘录：

class PublikationBasedView(PublikationCreateView): def get(self, request, *args, **kwargs): self.object = None try: self.object = KombiPublikation.objects.get(pk=self.kwargs['pk']) except ObjectDoesNotExist: raise Http404("Keinen Output unter dieser PubID gefunden.") #todo: delete the pk of all objects in forms in formset, else they stay the same and are also changed!! #fix: delete pk in objekt in order to save it as a new objekt - else based does not work at all! #self.object.pk=None form = KombiPublikationForm(instance=self.object) pubspr_formset = KombiPublikationSpracheFormset(instance=self.object) pubpers_formset = KombiPublikationPersonFormset(instance=self.object) return self.render_to_response( self.get_context_data( form=form, pubspr_formset=pubspr_formset, pubpers_formset=pubpers_formset, ) ) #its based on this create view class PublikationCreateView(LoginRequiredMixin, ShowNumberOfItems, CreateView): form_class = KombiPublikationForm template_name = 'output/pub_create.html' model = KombiPublikation def get(self, request, *args, **kwargs): self.object = None form_class = self.get_form_class() form = self.get_form(form_class) pubspr_formset = KombiPublikationSpracheFormset() pubpers_formset = KombiPublikationPersonFormset() return self.render_to_response( self.get_context_data( form=form, pubspr_formset=pubspr_formset, pubpers_formset=pubpers_formset ) ) def post(self, request, *args, **kwargs): self.object = None form_class = self.get_form_class() form = self.get_form(form_class) pubspr_formset = KombiPublikationSpracheFormset(self.request.POST) pubpers_formset = KombiPublikationPersonFormset(self.request.POST) if form.is_valid() and pubspr_formset.is_valid() and pubpers_formset.is_valid(): return self.form_valid(form, pubspr_formset, pubpers_formset) else: return self.form_invalid(form, pubspr_formset, pubpers_formset) def get_success_msg(self): return 'Ihr Output wurde erfolgreich unter PubID {} angelegt. Speicherort: {}. <br>'.format(self.object.pk, self.object.status) def form_valid(self, form, pubspr_formset, pubpers_formset): """ Called if all forms are valid.""" self.object = form.save() pubspr_formset.instance = self.object pubspr_formset.save() pubpers_formset.instance = self.object pubpers_formset.save() messages.success(self.request, self.get_success_msg()) return redirect(self.get_success_url()) def form_invalid(self, form, pubspr_formset, pubpers_formset): """ Called if whether a form is invalid. Re-renders data-filled forms and errors.""" return self.render_to_response( self.get_context_data( form=form, pubspr_formset=pubspr_formset, pubpers_formset=pubpers_formset, ))

Answer 1

一旦您将表单instance设置为绑定到该对象。所有更新都将是您传递的对象。

相反，您需要set the Form's initial value

使用initial在运行时声明表单字段的初始值。例如，您可能希望使用当前会话的用户名填写用户名字段。

然后在django.forms.models.model_to_dict有一个实用程序，它会为你提供initial所需的词典：

返回一个包含instance中适合作为Form initial关键字参数传递的数据的dict。

所以你需要做这样的事情：

from django.forms.models import model_to_dict

object = # Your code here...

# You don't want `id`. Possibly others...?
initial_data = model_to_dict(object, exclude=['id'])

form = YourFormClass(initial=initial_data)

# ...

希望这会有所帮助。

Answer 2

我解决了这个问题，因为它比预期的要复杂一点，我在这里分享我的发现 - 如果有人找到一个更简单的解决方案，可以随意添加另一个评论

这是视图中的最终get方法：

def get(self, request, *args, **kwargs):
    self.object = None
    try:
        self.object = KombiPublikation.objects.get(pk=self.kwargs['pk'])
    except ObjectDoesNotExist:
        raise Http404("Keinen Output unter dieser PubID gefunden.")

    #load all form initials and render the form correctly - but save new objects
    #1. make sure the main publikation object is saved as a new object:
    self.object.pk = None
    self.object.erstellungsdatum = datetime.now()
    form = KombiPublikationForm(instance=self.object)

    #2. get the corresponding querysets for sprache and person:
    pubspr = KombiPublikationSprache.objects.filter(publikation=self.kwargs['pk'])
    pubpers = KombiPublikationPerson.objects.filter(publikation=self.kwargs['pk'])

    #make a list of dicts out of the querysets and delete pk id and fk relations
    pubspr_listofdicts = []
    for pubspr in pubspr:
        pubspr_dict= model_to_dict(pubspr)
        del pubspr_dict['id']
        del pubspr_dict['publikation']
        pubspr_listofdicts.append(pubspr_dict)

    pubpers_listofdicts = []
    for pubpers in pubpers:
        pubpers_dict=model_to_dict(pubpers)
        del pubpers_dict['id']
        del pubpers_dict['publikation']
        pubpers_listofdicts.append(pubpers_dict)

    #create new formsets with the right amount of forms (leng(obj_listofdicts)
    KombiPublikationSpracheFormset = inlineformset_factory(KombiPublikation,
                                                           KombiPublikationSprache,
                                                           form=KombiPublikationSpracheForm,
                                                           extra=len(pubspr_listofdicts),
                                                           can_delete=True,
                                                           can_order=True,
                                                           min_num=1,
                                                           validate_min=True)

    KombiPublikationPersonFormset = inlineformset_factory(
        KombiPublikation,
        KombiPublikationPerson,
        form=KombiPublikationPersonForm,
        extra=len(pubpers_listofdicts),
        can_delete=True,
        can_order=True,
        min_num=0,
        validate_min=True)

    #initiate the formset with initial data:
    pubspr_formset = KombiPublikationSpracheFormset(instance=self.object, initial=pubspr_listofdicts)
    pubpers_formset = KombiPublikationPersonFormset(instance=self.object, initial=pubpers_listofdicts)


    return self.render_to_response(
        self.get_context_data(
            form=form,
            pubspr_formset=pubspr_formset,
            pubpers_formset=pubpers_formset,
        )
    )

Django - 通过预填充表单和相应的内联表单集，基于另一个对象创建一个新对象

2 个答案: