django - Django，在模板中显示ValidationError

Question

我创建了一个注册应用程序，用户可以在其中注册，提供用户名，电子邮件和密码。我所做的是确保电子邮件字段是唯一的(如下面的代码所示)。但是，如果用户输入已经使用的电子邮件地址，我无法弄清楚如何显示错误。

View

from django.shortcuts import render
from django.shortcuts import render_to_response
from django.http import HttpResponseRedirect
from django.core.context_processors import csrf

from forms import RegistrationForm

# Create your views here.
def register_user(request):
    if request.method == 'POST':
        form = RegistrationForm(request.POST)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect('../../membership/register_success')
        else:
            return HttpResponseRedirect('../../membership/register_failed')

    args = {}
    args.update(csrf(request))

    args['form'] = RegistrationForm()

    return render(request,'registration/registration_form.html', args)

def register_success(request):
    return render_to_response('registration/registration_success.html')

def register_failed(request):
    return render_to_response('registration/registration_failed.html')

形成

from django import forms
from django.contrib.auth.models import User
from django.contrib.auth.forms import UserCreationForm
from django.utils.translation import ugettext_lazy as _

    # forms.py
    class RegistrationForm(UserCreationForm):
        email = forms.EmailField(required=True)

        class Meta:
            model = User
            fields = ('username', 'email', 'password1', 'password2')

        def clean_email(self):
            email = self.cleaned_data.get('email')
            username = self.cleaned_data.get('username')

            if email and User.objects.filter(email=email).exclude(username=username).count():
                raise forms.ValidationError(_("This email address is already in use. Please supply a different email address."))
            return email

        def save(self, commit=True):
            user = super(RegistrationForm, self).save(commit=False)
            user.email = self.cleaned_data['email']
            if commit:
                user.save()
            return user

registration.html

    {% extends "base.html" %}
    {% block title %}Registration{% endblock %}

    {% block content %}

            <h1>Registration</h1>

            {% if form.errors %}
            <h1>ERRORRRRRR same email again???</h1>
            {% endif %}

            {% if registered %}
            <strong>thank you for registering!</strong>
            <a href="../../">Return to the homepage.</a><br />
            {% else %}
            <strong>register here!</strong><br />

            <form method="post" action="/membership/register/">{% csrf_token %}
                {{ form }}
                <input type="submit" name="submit" value="Register" />
            </form>
            {% endif %}

    {% endblock %}

Answer 1

您正在模板上显示带有{{ form }}的表单。默认情况下，它本身应该显示所有验证错误，但是对于您而言，如果表单无效，您将重定向到其他页面。因此，除非您通过GET参数传递错误，否则您将永远无法显示错误。您可以将 View 更改为此，以在注册页面本身上获取错误-

def register_user(request):
    args = {}
    if request.method == 'POST':
        form = RegistrationForm(request.POST)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect('../../membership/register_success')
    else:
        form = RegistrationForm()
    args['form'] = form

    return render(request,'registration/registration_form.html', args)

这是如何工作的，如果请求方法是POST，则使用POST数据启动表单，然后通过 is_valid()调用对其进行验证，因此，如果表单对象无效，则该表单对象现在具有验证错误消息。如果有效，则将其保存并重定向。如果无效，它将进入 args['form'] = form部分，其中将带有错误消息的表单对象设置为上下文，然后传递给渲染。

如果请求方法不是POST，则实例化一个没有数据的表单对象并将其传递给 render()。

现在，如果有任何错误，您的模板应在每个字段正下方显示所有错误消息。