django - 使用FormView和ModelForm更新模型

Question

我无法弄清楚如何使用ModelForm的FormView,这样它更新一个已经存在的实例？

此URL上的表单POST: r'/object/(?P<pk>)/'

我使用a ModelForm(而不是直接使用UpdateView),因为其中一个字段是必需的,我对它执行清理.

我基本上喜欢instance=...在FormView(在POST时)初始化表单时提供kwarg ,以便它绑定到在url中给出pk的对象.但我无法弄清楚在哪里做...

class SaveForm(ModelForm):
    somedata = forms.CharField(required=False)
    class Meta:
        model = SomeModel  # with attr somedata
        fields = ('somedata', 'someotherdata')
    def clean_somedata(self):
        return sometransformation(self.cleaned_data['somedata'])

class SaveView(FormView):
    form_class = SaveForm
    def form_valid(self, form):
        # form.instance here would be == SomeModel.objects.get(pk=pk_from_kwargs)
        form.instance.save()
        return ...

Answer 1

对于这个主题的任何进一步的访问者,是的,你可以做一个FormView像a CreateView和a 一样的行为UpdateView.这个,尽管有其他用户的一些意见,如果你想要一个Web表单的单个表单/ URL /页面来保存一些用户数据可以是很有意义的,这些用户数据可以是可选的,但只需要保存一次.您不希望有2个URL /视图,但只有一个页面/ URL显示表单,如果用户已保存模型,则填充以前要更新的数据.

想象一下像这样的"联系"模型:

from django.conf import settings
from django.db import models


class Contact(models.Model):
    """
    Contact details for a customer user.
    """
    user = models.OneToOneField(settings.AUTH_USER_MODEL)
    street = models.CharField(max_length=100, blank=True)
    number = models.CharField(max_length=5, blank=True)
    postal_code = models.CharField(max_length=7, blank=True)
    city = models.CharField(max_length=50, blank=True)
    phone = models.CharField(max_length=15)
    alternative_email = models.CharField(max_length=254)

所以,你写一个ModelFormfor,就像这样:

from django import forms

from .models import Contact


class ContactForm(forms.ModelForm):
    class Meta:
        model = Contact
        exclude = ('user',)  # We'll set the user later.

您的FormView"创建"和"更新"功能将如下所示:

from django.core.urlresolvers import reverse
from django.views.generic.edit import FormView

from .forms import ContactForm
from .models import Contact


class ContactView(FormView):
    template_name = 'contact.html'
    form_class = ContactForm
    success_url = reverse('MY_URL_TO_REDIRECT')

    def get_form(self, form_class):
        """
        Check if the user already saved contact details. If so, then show
        the form populated with those details, to let user change them.
        """
        try:
            contact = Contact.objects.get(user=self.request.user)
            return form_class(instance=contact, **self.get_form_kwargs())
        except Contact.DoesNotExist:
            return form_class(**self.get_form_kwargs())

    def form_valid(self, form):
        form.instance.user = self.request.user
        form.save()
        return super(ContactView, self).form_valid(form)

您甚至不需要pk在此示例的URL中使用a ,因为通过user一对一字段从DB检索对象.如果您有一个类似于此的案例,其中要创建/更新的模型与用户具有唯一的关系,则非常容易.

希望这有助于某人......

干杯.

Answer 2

经过与你的一些讨论,我仍然不明白为什么你不能使用UpdateView.如果我理解正确,这似乎是一个非常简单的用例.您有一个要更新的模型.并且您有一个自定义表单,在将其保存到该模型之前进行清洁.看起来像是UpdateView工作得很好.像这样:

class SaveForm(ModelForm):
    somedata = forms.CharField(required=False)

    class Meta:
        model = SomeModel  # with attr somedata
        fields = ('somedata', 'someotherdata')

    def clean_somedata(self):
        return sometransformation(self.cleaned_data['somedata'])


class SaveView(UpdateView):
    template_name = 'sometemplate.html'
    form_class = SaveForm
    model = SomeModel

    # That should be all you need. If you need to do any more custom stuff 
    # before saving the form, override the `form_valid` method, like this:

    def form_valid(self, form):
        self.object = form.save(commit=False)

        # Do any custom stuff here

        self.object.save()

        return render_to_response(self.template_name, self.get_context_data())

当然,如果我误解你,请告诉我.你应该可以让它工作.