当extra = 0时，在formset中显示表单验证错误

Question

我有一个具有以下自定义clean（）方法的表单：

def clean(self):
        cleaned_data = self.cleaned_data
        event_date = cleaned_data.get("event_date")
        location = cleaned_data.get("location")

        if event_date and location:
            cleaned_data['relevance'] = True
        else:
            cleaned_data['relevance'] = False
            raise forms.ValidationError("You need to supply at least Event and Location information")

        return cleaned_data

我想向用户显示ValidationError，以便他们可以修复错误 但是，创建此表单的formset具有extra = 0 set，如下所示：

CodingFormSet = formset_factory(CodingForm, extra=0)
if request.method=='POST':

        [...]

        elif "coding_form_save" in request.POST:
            formset = CodingFormSet(request.POST, prefix="coding_form")

            process_form(formset, request, current_page, paginator)

            update_location_set(formset, coded_events, location_queryset)

            redirect_to = "?page=%s" % current_page
            return HttpResponseRedirect(redirect_to)

def process_form(formset, request, current_page, paginator):
if formset.is_valid():
    for form in formset.forms:
        form = form.cleaned_data

        if form["relevance"] == False:
            pass
        elif form["relevance"] == True:

            event_form = EventRecordForm()

            event = event_form.save(commit=False)
            event.article = paginator.page(current_page).object_list[0]
            event.coder = request.user
            event.last_updated = datetime.datetime.today()
            event.event_date = form["event_date"]
            event.location = form["location"]
            event.actors = form["actors"]
            event.num_participants = form["num_participants"]
            event.issue = form["issue"]
            event.side = form["side"]
            event.scope = form["scope"]
            event.part_violence = form["part_violence"]
            event.sec_engagement = form["sec_engagement"]
            event.save()

    ##### Add info on who worked on the article when
    history_form = ArticleHistoryForm()
    article_history = history_form.save(commit=False)
    article_history.article = paginator.page(current_page).object_list[0]
    article_history.coder = request.user
    article_history.last_updated = datetime.datetime.now()
    article_history.save()

有没有办法保持额外= 0并仍然显示用户验证错误？
的更新： 感谢@Alasdair，我现在可以通过仅在表单有效时重定向来显示验证错误。代码现在看起来像这样：

def assignment(request, pk):
"""View for each assignment"""
if request.user.is_authenticated():

    #### Get correct articles
    assignment = get_object_or_404(Assignment, pk=pk)
    country = assignment.country.cowcode
    start_date = assignment.start_date
    end_date = assignment.end_date
    articles = Article.objects.filter(cowcode=country).filter(pubdate__range=(start_date,end_date))

    #### Pagination ####
    paginator = Paginator(articles, 1)
    page = request.GET.get('page')
    try:
        articles = paginator.page(page)
    except PageNotAnInteger:
        articles = paginator.page(1)
    except EmptyPage:
        articles = paginator(page(paginator.num_pages))

    # Check if on first page and enable redirect
    if page is None:
        current_page = 1
    else:
        current_page = page
    redirect_to = "?page=%s" % current_page

    ##### Show already created events on the page
    current_article = paginator.page(current_page).object_list[0]
    EventFormSet = modelformset_factory(EventRecord, can_delete=True, exclude=('coder','article','url','last_updated'), extra=0)
    event_queryset = EventRecord.objects.filter(article__id=current_article.id).filter(coder=request.user.id)
    coded_events = EventFormSet(queryset=event_queryset, prefix="event_form")

    last_updated = ArticleHistory.objects.filter(coder=request.user.id).filter(article__id=current_article.id).order_by('-pk')[0]
    ##### Create Forms    
    CodingFormSet = formset_factory(CodingForm, extra=0)

    ###### Get correct locations
    location_queryset = Geonames.objects.filter(cowcode=country).order_by('name')

    if request.method=='POST':

    ##### Check if coder wants to go to next page or stay
        if "coding_form_next" in request.POST:
            formset = CodingFormSet(request.POST, prefix="coding_form")


            process_form(formset, request, current_page, paginator, next_article, coded_events, location_queryset)

            update_location_set(formset, coded_events, location_queryset)

            #current_page = int(current_page) + 1
            #redirect_to = "?page=%s" % current_page
            #return HttpResponseRedirect(redirect_to)

        elif "coding_form_save" in request.POST:
            formset = CodingFormSet(request.POST, prefix="coding_form")


            process_form(CodingFormSet, formset, request, current_page, paginator, next_article, coded_events, location_queryset)

            update_location_set(formset, coded_events, location_queryset)

            #redirect_to = "?page=%s" % current_page
            #return HttpResponseRedirect(redirect_to)

        elif 'add_event' in request.POST:

            cp = request.POST.copy()
            cp['coding_form-TOTAL_FORMS'] = int(cp['coding_form-TOTAL_FORMS'])+ 1
            formset = CodingFormSet(cp,prefix='coding_form')

            update_location_set(formset, coded_events, location_queryset)
        elif 'save_changes' in request.POST:
            formset = CodingFormSet(prefix="coding_form")
            changed_events = EventFormSet(request.POST, prefix="event_form")
            instances = changed_events.save()

            update_location_set(formset, coded_events, location_queryset)

            history_form = ArticleHistoryForm()
            article_history = history_form.save(commit=False)
            article_history.article = paginator.page(current_page).object_list[0]
            article_history.coder = request.user
            article_history.last_updated = datetime.datetime.now()
            article_history.save()

            EventFormSet = modelformset_factory(EventRecord, can_delete=True, exclude=('coder','article','url','last_updated'), extra=0)
            event_queryset = EventRecord.objects.filter(article__id=current_article.id).filter(coder=request.user.id)
            coded_events = EventFormSet(queryset=event_queryset, prefix="event_form")
    else:
        formset = CodingFormSet(request.POST or None,prefix="coding_form")

        update_location_set(formset, coded_events, location_queryset)

else:
    print ERROR
return render(request, 'coding/assignment.html', 
{'articles':articles,'assignment':assignment,'formset':formset,'coded_events':coded_events,'last_updated':last_updated})

def process_form(CodingFormSet, formset, request, current_page, paginator, next_article, coded_events, location_queryset):
if formset.is_valid():
    for form in formset.forms:
        form = form.cleaned_data

        if form["relevance"] == False:
            pass
        elif form["relevance"] == True:

            event_form = EventRecordForm()

            event = event_form.save(commit=False)
            event.article = paginator.page(current_page).object_list[0]
            event.coder = request.user
            event.last_updated = datetime.datetime.today()
            event.event_date = form["event_date"]
            event.location = form["location"]
            event.actors = form["actors"]
            event.num_participants = form["num_participants"]
            event.issue = form["issue"]
            event.side = form["side"]
            event.scope = form["scope"]
            event.part_violence = form["part_violence"]
            event.sec_engagement = form["sec_engagement"]
            event.save()

    ##### Add info on who worked on the article when
    history_form = ArticleHistoryForm()
    article_history = history_form.save(commit=False)
    article_history.article = paginator.page(current_page).object_list[0]
    article_history.coder = request.user
    article_history.last_updated = datetime.datetime.now()
    article_history.save()


    redirect_to = "?page=%s" % current_page
    return HttpResponseRedirect(redirect_to)

然而，现在有什么不同，最好在三张图片中显示：
在旧代码中，在点击save之后，编码器会看到以下内容：

现在，在点击save之后，编码员看到了这一点：
看起来他根本没有点击保存。

只有在再次点击save或重新加载页面后，他或她才会看到：

我想回到第一张图片，其中编码人员看到编码事件，而没有新的表格，其中包含相同的信息。请注意，他的发生是因为我改变了两行代码而没有做任何其他事情 非常感谢任何帮助！

Answer 1

我不认为让extra=0与是否显示错误有关。

以下模式在处理formset时非常常见：

def my_view(request):
    if request.method == "POST"
        formset = MyFormSet(request.POST, prefix="coding_form")
        if formset.is_valid():
            do_something_with_formset()
            return HttpResponseRedirect("/success_url/")
    else:
        formset = MyFormSet(request.POST, prefix="coding_form")
    return render(request, "my_template.html", {'formset': formset}

当请求方法为GET时，将呈现空白formset。当formset无效时，将呈现formset，并显示错误。我们只有在formset有效时才重定向。

在您的情况下，无论表单集是否有效，您始终在请求方法为POST时重定向。因此，当formset无效时，您永远不会看到错误。