python - form_Valid 函数在 Django 中是如何工作的？

Question

返回行上的这个表单对象是什么，它是提交表单收到的表单对象吗？ .因为我们用 return super().form_valid(form) 返回它。
它可以像上下文变量一样访问吗？从由 success_url 表示的模板 .also form_valid 指向 success_url ，既然在做 super() ，它不应该指向父类的 success_url 。但是为什么它会转到ContactView 的success_url。

class ContactView(FormView):
    template_name = 'contact.html'
    form_class = ContactForm
    success_url = '/thanks/'

    def form_valid(self, form):
        # This method is called when valid form data has been POSTed.
        # It should return an HttpResponse.
        form.send_email()
        return super().form_valid(form)

Answer 1

What is this form object on the return line?

form是 ContactForm Django 构造来验证 POST 请求的实例。例如，您可以通过以下方式从表单中获取清理过的数据:

class ContactView(FormView):
    template_name = 'contact.html'
    form_class = ContactForm
    success_url = '/thanks/'

    def form_valid(self, form):
        # This method is called when valid form data has been POSTed.
        # It should return an HttpResponse.
        form.send_email()
        print(form.cleaned_data)
        return super().form_valid(form)

FormView因此将构造一个 ContactForm与 request.POST和 request.FILES ，并检查 form.is_valid() .如果是，它会调用 form_valid使用此表单实例。

since were doing super(), shouldnt it point to the success_url of the parent class.

否 . super()是一个代理对象，它将向上移动 MRO 并因此调用父方法，但该父方法是 implemented as [GitHub] :

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

self然而对象仍然是 ContactView对象，所以 self.get_success_url()将返回 success_url .

然而，通常， reverse_lazy [Django-doc]用来。这样你就可以提供 View 的名称，Django 可以自动计算 URL:

from django.urls import reverse_lazy

class ContactView(FormView):
    template_name = 'contact.html'
    form_class = ContactForm
    success_url = reverse_lazy('name-of-thanks-view')