在FormView form_valid方法中更新上下文数据？ [英] Updating context data in FormView form_valid method?

问题描述

我有一个类 QuestionView ，它来源于 FormView 类。这里
是一个代码片段来解释我的问题：

I have a class QuestionView which is derived from the FormView class. Here is a code snippet to explain my problem:

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，我在 form_valid 和$ b $中更新一组上下文变量b我打算在模板中使用这些更新的值 - 因此在上下文字典中的变量。此代码的问题是，
context_var1 中的更改未被看到 - 可能是因为 get_context_data 在$ code> form_valid 方法之前调用
。是否有一个解决方案
这个？

As shown above, I update a set of context variables in form_valid and I intend to use the updated values of these in the template - hence the variables in the context dictionary. The problem with this code is that the change in context_var1 isn't seen - might be because get_context_data is called before the form_valid method. Is there is a workaround for this?

推荐答案

我这样做与 form_invalid 。以下是我如何做：

I do this with form_invalid. Here's how I do it:

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)

你可以做同样的但是form_valid。通常，form_valid的正文如下所示：

You could do the same but for form_valid. Normally the body of form_valid looks like this:

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

你必须覆盖 post 和 form_valid ，因为发布调用 form_valid 。

You would have to override both post and form_valid, because post calls 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，只是为了澄清，这个问题存在的原因是 ProcessFormView 类的 get 方法已损坏。它通常如下所示：

oh and just to clarify, the reason this problem exists is that the ProcessFormView class's get method is broken. It normally looks like this:

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抛出去，（._。）

It just throws the kwargs away (._.)

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