16

我有一个QuestionView派生自该类的FormView类。这是一个代码片段来解释我的问题：

class QuestionView(FormView):
    ...
    context_var1 = y

    def form_valid (self, form):
        ...
        self.context_var1 = x
        ...

    def get_context_data(self, **kwargs):
        ...
        context['context_var1'] = self.context_var1
        ...
        return context

如上所示，我更新了一组上下文变量，form_valid并打算在模板中使用这些变量的更新值 - 因此context字典中的变量。这段代码的问题 context_var1是看不到更改 - 可能是因为get_context_data在方法之前调用form_valid。有解决方法吗？

4

5 回答 5

26

我用form_invalid. 这是我的做法：

from django.views.generic import FormView

class ContextFormView(FormView):
    def get(self, request, *args, **kwargs):
        form_class = self.get_form_class()
        form = self.get_form(form_class)
        context = self.get_context_data(**kwargs)
        context['form'] = form
        return self.render_to_response(context)

    def post(self, request, *args, **kwargs):
        form_class = self.get_form_class()
        form = self.get_form(form_class)
        if form.is_valid():
            return self.form_valid(form)
        else:
            return self.form_invalid(form, **kwargs)

    def form_invalid(self, form, **kwargs):
        context = self.get_context_data(**kwargs)
        context['form'] = form
        return self.render_to_response(context)

除了 form_valid，你也可以这样做。通常 form_valid 的主体如下所示：

def form_valid(self, form):
    return HttpResponseRedirect(self.get_success_url())

您必须同时覆盖postand form_valid，因为post调用form_valid.

def post(self, request, *args, **kwargs):
    form_class = self.get_form_class()
    form = self.get_form(form_class)
    if form.is_valid():
        return self.form_valid(form, **kwargs)
    else:
        return self.form_invalid(form, **kwargs)

def form_valid(self, form, **kwargs):
    # take some other action here
    return HttpResponseRedirect(self.get_success_url())

哦，澄清一下，这个问题存在的原因是ProcessFormView类的get方法被破坏了。它通常看起来像这样：

def get(self, request, *args, **kwargs):
    form_class = self.get_form_class()
    form = self.get_form(form_class)
    return self.render_to_response(self.get_context_data(form=form))

它只是把kwargs扔掉(._.)

于 2011-11-22T05:56:59.727 回答
5

在 Django 2.0.1 中，您可以通过覆盖get_context_data或来插入上下文数据form_invalid。

在您的情况下，您可以执行以下覆盖之一：

class QuestionView(FormView):
    ...

    def form_invalid(self, form):
        """If the form is invalid, render the invalid form."""
        return self.render_to_response(
            self.get_context_data(
                form=form, 
                context_key=some_value
            )
        )

或者：

class QuestionView(FormView):
    ...

    def get_context_data(self, **kwargs):
        if 'context_key' not in kwargs:  # set value if not present
            kwargs['context_key'] = some_value
        return super().get_context_data(**kwargs)

Django 2.0.1 在后台将表单插入到get_context_data.

# File: django.views.generic.edit

class FormMixin(ContextMixin):
    ...

    def form_valid(self, form):
        """If the form is valid, redirect to the supplied URL."""
        return HttpResponseRedirect(self.get_success_url())

    def form_invalid(self, form):
        """If the form is invalid, render the invalid form."""
        return self.render_to_response(self.get_context_data(form=form))

    def get_context_data(self, **kwargs):
        """Insert the form into the context dict."""
        if 'form' not in kwargs:
            kwargs['form'] = self.get_form()
        return super().get_context_data(**kwargs)
于 2018-01-31T18:22:08.413 回答
3

在views.py

class UploadTest(FormView):
    template_name = 'test.html'
    ....
    plus_context = dict()

    def form_valid(self, form):
        ...
        self.plus_context['you_want_context'] = value
        ...
        return super(UploadTest, self).form_valid(form)

    def get_context_data(self, **kwargs):
        context = super(UploadTest, self).get_context_data(**kwargs)
        context['plus_context_key'] = self.plus_context
        return context

在 test.html

<html>
    ....
    <body>
    ....
    // first post can not get plus_context_key
    {% if plus_context_key %}
        {{ plus_context_key.you_want_context }}
    {% endif %}    
    </body>
</html>

我只是在 Django 1.10.3 中找到了这种方式。希望能帮到你

于 2016-11-17T10:32:07.663 回答
0

也许您可以使用这种方法：

class SomeView(View):

    def post(self, request):
        my_form = MyForm(request.POST)
        if my_form.is_valid():
            context['foo'] = 'bar'

        return render(request, 'valid/path.html', context)
于 2015-05-16T12:19:01.590 回答
0

如果保存成功，则通过 plus_context：

class SomeUpdateView(UpdateView):
    ...
    success_url = reverse_lazy('SomeUpdateView')
    plus_context = dict()

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        if self.plus_context:
            context['success'] = self.plus_context['pass_to_view_just_after_save_successful']
        return context

    def form_valid(self, form, **kwargs):
        self.object.save()
        self.plus_context['pass_to_view_just_after_save_successful'] = 'Save successful!'
        return super(SomeUpdateView, self).form_valid(form)

在模板中类似于：

{% if success %}
<p>{{ success }}</p>
{% endif %}
于 2021-10-26T18:20:52.193 回答