form.ValidationError 未显示在模板中

Question

我是 Django 的新手，所以请原谅我的一些错误。我正在尝试为电子邮件创建验证系统并将这些错误（如果有）打印到模板。澄清一下，我可以创建新用户并重定向到登录页面，只是无法显示错误消息。如果这是一个微不足道的问题，我深表歉意，但我已经坚持了 2 天了。我在 youtube: and i have tried to follow this 上试过这个视频，但没用。

forms.py

from django.forms import ModelForm
from django.contrib.auth.forms import UserCreationForm
from django.contrib.auth.models import User
from django import forms

# This class will overwrite origginal UserCreationForm0
class CreateUserForm(UserCreationForm):
    email = forms.EmailField(required = True)
    class Meta:
        model = User
        # this will add email to our register_form
        fields = [
            'username',
            'email',
            'password1',
            'password2'
        ]
    def clean(self):
        cleaned_data = super(CreateUserForm, self).clean()
        email = self.cleaned_data.get('email')
        if User.objects.filter(email=email).exists():
            raise forms.ValidationError('User with same email already exists')
        return cleaned_data

views.py

from django.shortcuts import render, redirect
from .forms import CreateUserForm
from django.contrib.auth import login, authenticate, logout
from django.contrib.auth.forms import AuthenticationForm
from django.contrib import messages
# Create your views here.
def registration_page(request):
    if request.user.is_authenticated:
        return redirect('')
    else:
        form = CreateUserForm()
        if request.method == 'POST':
            form = CreateUserForm(request.POST)
            if form.is_valid():
                form.save()
                messages.success(request, 'User has been successefly registered, Please Log In!')
                return redirect('accounts:login')
        else:
            CreateUserForm()
        context = {
            'form': form
        }
        return render(request, 'accounts/register.html', context)

register.html

<form class="form-horizontal" method="post">
                                  {% csrf_token %}
                                    <div class="form-group">
                                        <label for="email" class="cols-sm-2 control-label">Your Email</label>
                                        <div class="cols-sm-10">
                                            <div class="input-group">
                                                <span class="input-group-addon"><i class="fa fa-envelope fa" aria-hidden="true"></i></span>
                                                {{form.email}}
                                            </div>
                                        </div>
                                    </div>
                                    <div class="form-group">
                                        <label for="username" class="cols-sm-2 control-label">Username</label>
                                        <div class="cols-sm-10">
                                            <div class="input-group">
                                                <span class="input-group-addon"><i class="fa fa-users fa" aria-hidden="true"></i></span>
                                                {{form.username}}
                                            </div>
                                        </div>
                                    </div>
                                    <div class="form-group">
                                        <label for="password" class="cols-sm-2 control-label">Password</label>
                                        <div class="cols-sm-10">
                                            <div class="input-group">
                                                <span class="input-group-addon"><i class="fa fa-lock fa-lg" aria-hidden="true"></i></span>
                                                {{form.password1}}
                                            </div>
                                        </div>
                                    </div>
                                    <div class="form-group">
                                        <label for="confirm" class="cols-sm-2 control-label">Confirm Password</label>
                                        <div class="cols-sm-10">
                                            <div class="input-group">
                                                <span class="input-group-addon"><i class="fa fa-lock fa-lg" aria-hidden="true"></i></span>
                                                {{form.password2}}
                                            </div>
                                        </div>
                                    </div>
                                    <p>{{form.email.errors}}</p>
                                    <p>{{form.password.errors}}</p>
                                    <div class="form-group ">
                                        <input type="submit" value="Register" class="btn btn-primary btn-lg btn-block login-button">
                                    </div>
                                    <div class="login-register">
                                        <a href="{% url 'accounts:login' %}">Login</a>
                                    </div>
                                </form>

Answer 1

clean 方法引发的没有附加字段的错误被添加到 .non_field_errors() [Django-doc]。因此你应该渲染这些：

<p>{{ form<b>.non_field_errors</b> }}</p>
<p>{{ form<b>.username.errors</b> }}</p>
<p>{{ form<b>.email.errors</b> }}</p>
<p>{{ form<b>.password1.errors</b> }}</p>
<p>{{ form<b>.password2.errors</b> }}</p>

也就是说，(1) 这个错误是 field-specific，所以你最好在 clean_email 方法中清除它； (2) 如果 model 字段被标记为唯一，Django 模型表单可以检查唯一性。

class CreateUserForm(UserCreationForm):
    email = forms.EmailField(required=True)
    
    class Meta:
        model = User
        fields = [
            'username',
            'email',
            'password1',
            'password2'
        ]
    
    def <b>clean_email</b>(self):
        email = self.cleaned_data['email']
        if User.objects.exclude(<b>pk=self.instance.pk</b>).filter(<b>email=email</b>).exists():
            raise forms.ValidationError('User with same email already exists')
        return email

如果表单具有已保存在数据库中的包装实例，则此处的 .exclude(…) 很有用。

Answer 2

你可以添加这行

<form class="form-horizontal" method="post">
                              {% csrf_token %}
                                <div class="form-group">
                                    <label for="email" class="cols-sm-2 control-label">Your Email</label>
                                    <div class="cols-sm-10">
                                        <div class="input-group">
                                            <span class="input-group-addon"><i class="fa fa-envelope fa" aria-hidden="true"></i></span>
                                            {{form.email}}
                                        </div>
                                    </div>
                                </div>
                                <div class="form-group">
                                    <label for="username" class="cols-sm-2 control-label">Username</label>
                                    <div class="cols-sm-10">
                                        <div class="input-group">
                                            <span class="input-group-addon"><i class="fa fa-users fa" aria-hidden="true"></i></span>
                                            {{form.username}}
                                        </div>
                                    </div>
                                </div>
                                <div class="form-group">
                                    <label for="password" class="cols-sm-2 control-label">Password</label>
                                    <div class="cols-sm-10">
                                        <div class="input-group">
                                            <span class="input-group-addon"><i class="fa fa-lock fa-lg" aria-hidden="true"></i></span>
                                            {{form.password1}}
                                        </div>
                                    </div>
                                </div>
                                <div class="form-group">
                                    <label for="confirm" class="cols-sm-2 control-label">Confirm Password</label>
                                    <div class="cols-sm-10">
                                        <div class="input-group">
                                            <span class="input-group-addon"><i class="fa fa-lock fa-lg" aria-hidden="true"></i></span>
                                            {{form.password2}}
                                        </div>
                                    </div>
                                </div>
                                <p>{{form.email.errors}}</p>
                                <p>{{form.password2.errors}}</p>
                                <p>{{form.username.errors}}</p>
                                <div class="form-group ">
                                    <input type="submit" value="Register" class="btn btn-primary btn-lg btn-block login-button">
                                </div>
                                <div class="login-register">
                                    <a href="{% url 'accounts:login' %}">Login</a>
                                </div>
                            </form>

form.ValidationError 未显示在模板中

form.ValidationError is not showing in template

python

forms

django

validationerror