Django，在模板中显示 ValidationError [英] Django, show ValidationError in template

问题描述

我创建了一个注册应用程序，用户可以在其中注册并提供用户名、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).但我不知道如何在用户输入已在使用的电子邮件地址时显示错误.

I create a registation app, where users can register providing a username, email and a password. What I did is make sure that the email field is unique(as you can see in the code below). But I can't figure out how I can show the error in case the a user enters an email address that is already in use.

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')

表格

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

注册.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 %}

推荐答案

您在模板上显示带有 {{ form }} 的表单.默认情况下，它本身应该显示所有验证错误，但在您的情况下，如果表单无效，您将重定向到其他页面.因此，除非您使用 GET 参数传递错误，否则您永远无法显示错误.您可以将视图更改为此以获取注册页面本身的错误 -

You're showing the form with {{ form }} on the template. That itself should show all the validation errors by default, but in your case, you're redirecting to some other page if the form is invalid. So you can never show the errors unless you pass the errors with the GET parameters. You could change your view to this to get the errors on the signup page itself -

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，则表单使用 POST 数据启动，然后使用 is_valid() 调用对其进行验证，因此表单对象现在具有验证错误如果无效，则发送消息.如果有效，则保存并重定向.如果无效，则进入 args['form'] = form 部分，其中包含错误消息的表单对象设置为上下文，然后传递给渲染.

How this works is, if the request method is POST, the form gets initiated with the POST data, then it's validated with the is_valid() call, so the form object now has the validation error messages if it's invalid. If it's valid, it's saved and redirected. If not valid, it comes to the args['form'] = form part where the form object with the error messages is set to the context and then passed to render.

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传递给 render().

If the request method is not POST, then a form object with no data is instantiated and passed to render().

现在，如果有任何错误，您的模板应该会在每个字段下方显示所有错误消息.

Now your template should show all the error messages just below each field if there is any error.

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