使用表单后修改上下文

Question

我有一个视图，显示具有特定标签的对象的列表。

class AllView(ListView):

    context_object_name = 'facts'
    template_name = 'facts_blog/all_facts.html'

    def get_context_data(self, **kwargs):
        context = super(AllView, self).get_context_data(**kwargs)
        if 'TagForm' not in context:
            context['TagForm'] = TagForm()
        return context

    def get_queryset(self):
        form = TagForm(self.request.GET)
        if form.is_valid():
            context = RequestContext(self.request)
            return self.send_results(form.cleaned_data['tag'])
        else:
            return Fact.objects.all()

    def send_results(self, tag):
        return Fact.objects.filter(tags__slug=tag)

我想将form.cleaned_data ['tag']返回到模板，但是我已经使用过get_context_data ...我应该怎么做？

Answer 1

如果我了解您的意思，则希望在上下文字典中包含“标记”，而ListView查询集将返回与标记关联的“事实”实例。 正确？

如果您查看Django的BaseListView则get方法将首先调用get_queryset ，然后在调用render_to_response之前，它将调用您的get_context_data方法：

class BaseListView(MultipleObjectMixin, View):
    """
    A base view for displaying a list of objects.
    """
    def get(self, request, *args, **kwargs):
        self.object_list = self.get_queryset()
        allow_empty = self.get_allow_empty()

        # [snip]
        # some code not related to this omitted
        # [snip]

        context = self.get_context_data()
        return self.render_to_response(context)

您可以做的是在get_queryset方法中设置一个属性（ self.object ），以存储经过验证的表单中的“标签”，然后在get_context_data方法中对其进行检索，以便将其填充到上下文字典中：

def get_queryset(self):
    form = TagForm(self.request.GET)
    if form.is_valid():
        context = RequestContext(self.request)
        # set self.object to the "tag"
        self.object = form.cleaned_data['tag']
        return self.send_results(self.object)
    else:
        # set self.object to None since the form is not validated
        self.object = None
        return Fact.objects.all()

def get_context_data(self, **kwargs):
    context = super(AllView, self).get_context_data(**kwargs)
    if 'TagForm' not in context:
        context['TagForm'] = TagForm()
    # put self.object in the context dict
    context['tag'] = self.object
    return context

然后，您的模板将具有一个名为tag ，其值为“ tag”或None 。

Answer 2

假设表单的操作通过GET请求返回到AllView视图，您可以通过以下方式修改get_context_data ：

def get_context_data(self, **kwargs):
    context = super(AllView, self).get_context_data(**kwargs)
    if 'TagForm' not in context:
        context['TagForm'] = TagForm()

    tag_form = TagForm(self.request.GET)
    if tag_form.is_valid():
        context['tag'] = tag_form.cleaned_data.get('tag')

    return context

希望它能解决问题。