{"title":"Formulärhantering med klassbaserade vyer","version":"6.1","locale":"sv","docname":"topics/class-based-views/generic-editing","url":"/sv/6.1/topics/class-based-views/generic-editing/","canonical":"https://djangodocs.dev/sv/6.1/topics/class-based-views/generic-editing/","summary":"Formulärhantering har i allmänhet 3 vägar: Initial GET (blankett eller förifyllt formulär) POST med ogiltiga data (vanligtvis visas formuläret på nytt med fel) POST…","html":"

Formulärhantering med klassbaserade vyerLink to this heading#

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Formulärhantering har i allmänhet 3 vägar:

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Att implementera detta själv resulterar ofta i en hel del upprepad boilerplate-kod (se Använda ett formulär i en vy). För att hjälpa till att undvika detta tillhandahåller Django en samling generiska klassbaserade vyer för formulärbehandling.

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Grundläggande formerLink to this heading#

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Givet ett kontaktformulär:

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forms.py
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Python
from django import forms\n\n\nclass ContactForm(forms.Form):\n    name = forms.CharField()\n    message = forms.CharField(widget=forms.Textarea)\n\n    def send_email(self):\n        # send email using the self.cleaned_data dictionary\n        pass\n
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Vyn kan byggas upp med hjälp av en FormView:

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Vyer.py
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Python
from myapp.forms import ContactForm\nfrom django.views.generic.edit import FormView\n\n\nclass ContactFormView(FormView):\n    template_name = "contact.html"\n    form_class = ContactForm\n    success_url = "/thanks/"\n\n    def form_valid(self, form):\n        # This method is called when valid form data has been POSTed.\n        # It should return an HttpResponse.\n        form.send_email()\n        return super().form_valid(form)\n
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Anteckningar:

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ModellformerLink to this heading#

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Generic views really shine when working with models. These generic\nviews will automatically create a ModelForm, so long as\nthey can work out which model class to use:

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Model form views provide a\nform_valid() implementation\nthat saves the model automatically. You can override this if you have any\nspecial requirements; see below for examples.

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You don’t even need to provide a success_url for\nCreateView or\nUpdateView - they will use\nget_absolute_url() on the model object if\navailable.

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Om du vill använda en anpassad ModelForm (t.ex. för att lägga till extra validering), ange form_class på din vy.

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First we need to add get_absolute_url() to our\nAuthor class:

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modeller.py
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Python
from django.db import models\nfrom django.urls import reverse\n\n\nclass Author(models.Model):\n    name = models.CharField(max_length=200)\n\n    def get_absolute_url(self):\n        return reverse("author-detail", kwargs={"pk": self.pk})\n
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Sedan kan vi använda CreateView och dess vänner för att göra det faktiska arbetet. Lägg märke till hur vi bara konfigurerar de generiska klassbaserade vyerna här; vi behöver inte skriva någon logik själva:

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Vyer.py
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Python
from django.urls import reverse_lazy\nfrom django.views.generic.edit import CreateView, DeleteView, UpdateView\nfrom myapp.models import Author\n\n\nclass AuthorCreateView(CreateView):\n    model = Author\n    fields = ["name"]\n\n\nclass AuthorUpdateView(UpdateView):\n    model = Author\n    fields = ["name"]\n\n\nclass AuthorDeleteView(DeleteView):\n    model = Author\n    success_url = reverse_lazy("author-list")\n
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Attributet fields fungerar på samma sätt som attributet fields på den inre Meta klassen på ModelForm. Om du inte definierar formulärklassen på ett annat sätt krävs attributet och vyn kommer att ge upphov till ett ImproperlyConfigured undantag om det inte är det.

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Om du anger både attributen fields och form_class, kommer ett ImproperlyConfigured undantag att uppstå.

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Slutligen kopplar vi in dessa nya vyer i URLconf:

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urls.py
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Python
from django.urls import path\nfrom myapp.views import AuthorCreateView, AuthorDeleteView, AuthorUpdateView\n\nurlpatterns = [\n    # ...\n    path("author/add/", AuthorCreateView.as_view(), name="author-add"),\n    path("author/<int:pk>/", AuthorUpdateView.as_view(), name="author-update"),\n    path("author/<int:pk>/delete/", AuthorDeleteView.as_view(), name="author-delete"),\n]\n
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Modeller och request.userLink to this heading#

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För att spåra den användare som skapade ett objekt med hjälp av en CreateView kan du använda en anpassad ModelForm för att göra detta. Lägg först till den främmande nyckelrelationen i modellen:

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modeller.py
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Python
from django.contrib.auth.models import User\nfrom django.db import models\n\n\nclass Author(models.Model):\n    name = models.CharField(max_length=200)\n    created_by = models.ForeignKey(User, on_delete=models.CASCADE)\n\n    # ...\n
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In the view, ensure that you don’t include created_by in the list of fields\nto edit, and override\nform_valid() to add the user:

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Vyer.py
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Python
from django.contrib.auth.mixins import LoginRequiredMixin\nfrom django.views.generic.edit import CreateView\nfrom myapp.models import Author\n\n\nclass AuthorCreateView(LoginRequiredMixin, CreateView):\n    model = Author\n    fields = ["name"]\n\n    def form_valid(self, form):\n        form.instance.created_by = self.request.user\n        return super().form_valid(form)\n
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LoginRequiredMixin prevents users who\naren’t logged in from accessing the form. If you omit that, you’ll need to\nhandle unauthorized users in form_valid().

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Exempel på förhandling om innehållLink to this heading#

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Här är ett exempel som visar hur du kan gå tillväga för att implementera ett formulär som fungerar med ett API-baserat arbetsflöde såväl som ”vanliga” formulärposts:

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Code
from django.http import JsonResponse\nfrom django.views.generic.edit import CreateView\nfrom myapp.models import Author\n\n\nclass JsonableResponseMixin:\n    """\n    Mixin to add JSON support to a form.\n    Must be used with an object-based FormView (e.g. CreateView)\n    """\n\n    def form_invalid(self, form):\n        response = super().form_invalid(form)\n        if self.request.accepts("text/html"):\n            return response\n        else:\n            return JsonResponse(form.errors, status=400)\n\n    def form_valid(self, form):\n        # We make sure to call the parent's form_valid() method because\n        # it might do some processing (in the case of CreateView, it will\n        # call form.save() for example).\n        response = super().form_valid(form)\n        if self.request.accepts("text/html"):\n            return response\n        else:\n            data = {\n                "pk": self.object.pk,\n            }\n            return JsonResponse(data)\n\n\nclass AuthorCreateView(JsonableResponseMixin, CreateView):\n    model = Author\n    fields = ["name"]\n
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I exemplet ovan antas att om klienten har stöd för text/html, så kommer de att föredra det. Detta kanske dock inte alltid är sant. Vid begäran om en .css-fil kommer många webbläsare att skicka rubriken Accept: text/css,*/*;q=0.1, vilket indikerar att de föredrar CSS, men allt annat går bra. Detta innebär att request.accepts("text/html") kommer att vara True.

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För att bestämma rätt format, med hänsyn till klientens preferenser, använd django.http.HttpRequest.get_preferred_type():

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Code
class JsonableResponseMixin:\n    """\n    Mixin to add JSON support to a form.\n    Must be used with an object-based FormView (e.g. CreateView).\n    """\n\n    accepted_media_types = ["text/html", "application/json"]\n\n    def dispatch(self, request, *args, **kwargs):\n        if request.get_preferred_type(self.accepted_media_types) is None:\n            # No format in common.\n            return HttpResponse(\n                status_code=406, headers={"Accept": ",".join(self.accepted_media_types)}\n            )\n\n        return super().dispatch(request, *args, **kwargs)\n\n    def form_invalid(self, form):\n        response = super().form_invalid(form)\n        accepted_type = self.request.get_preferred_type(self.accepted_media_types)\n        if accepted_type == "text/html":\n            return response\n        elif accepted_type == "application/json":\n            return JsonResponse(form.errors, status=400)\n\n    def form_valid(self, form):\n        # We make sure to call the parent's form_valid() method because\n        # it might do some processing (in the case of CreateView, it will\n        # call form.save() for example).\n        response = super().form_valid(form)\n        accepted_type = self.request.get_preferred_type(self.accepted_media_types)\n        if accepted_type == "text/html":\n            return response\n        elif accepted_type == "application/json":\n            data = {\n                "pk": self.object.pk,\n            }\n            return JsonResponse(data)\n
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","rootId":"form-handling-with-class-based-views","toc":[{"title":"Grundläggande former","anchor":"basic-forms","children":[]},{"title":"Modellformer","anchor":"model-forms","children":[]},{"title":"Modeller och request.user","anchor":"models-and-request-user","children":[]},{"title":"Exempel på förhandling om innehåll","anchor":"content-negotiation-example","children":[]}],"breadcrumbs":[{"docname":"topics/index","title":"Använda Django","url":"/sv/6.1/topics/"},{"docname":"topics/class-based-views/index","title":"Klassbaserade åsikter","url":"/sv/6.1/topics/class-based-views/"}],"prev":{"docname":"topics/class-based-views/generic-display","title":"Inbyggda klassbaserade generiska vyer","url":"/sv/6.1/topics/class-based-views/generic-display/"},"next":{"docname":"topics/class-based-views/mixins","title":"Använda mixins med klassbaserade vyer","url":"/sv/6.1/topics/class-based-views/mixins/"},"formats":{"html":"/sv/6.1/topics/class-based-views/generic-editing/","markdown":"/sv/6.1/topics/class-based-views/generic-editing.md","json":"/sv/6.1/topics/class-based-views/generic-editing.json"},"source":"https://github.com/django/django/blob/stable/6.1.x/docs/topics/class-based-views/generic-editing.txt","official":"https://docs.djangoproject.com/sv/6.1/topics/class-based-views/generic-editing/","inVersions":["6.1","6.0","5.2"],"inLocales":["en","sv","zh-hans","ga","fr","ja","id","it","pt-br","ko","es","el","pl"]}