我无法弄清楚如何在Django（1.7）模板中打印所有表单错误消息，尽管遵循官方文档和其他地方的建议。
我有一个帐户用户/通过admin / admin。我故意将LoginForm中允许的最小用户名长度更改为6，以便获得“错误长度”错误，而不是“错误的用户/通过组合”错误（底部的完整表单/视图代码）。
根据the official docs，以下内容应打印所有错误消息：
{% if form.errors %}
{% for error in form.errors %}
<li><strong>{{ error|escape }}</strong></li>
{% endfor %}
{% endif %}
但它只打印“用户名”这个词。
将其更改为
{% for error, msg in form.errors %}
<li><strong>{{ error|escape }}: {{ msg|escape }}</strong></li>
{% endfor %}
打印
Username
u: s
咦？
我也试过这个，但它没有打印出来：
{% for error, msg in form.non_field_errors %}
<li><strong>{{ error|escape }}: {{ msg|escape }}</strong></li>
{% endfor %}
与此相同：
{% for error in form.non_field_errors %}
{{error}}
{% endfor %}
和此：
{% for error in form.non_field_errors %}
{{error.msg}}
{% endfor %}
this question中接受的答案表明了这一点：
{% for key,value in form.errors.items %}
{% for error in value %}
<li>{{ error|escape }}</li>
{% endfor %}
{% endfor %}
但是，无论escape过滤器是否存在，都会产生
TypeError at /auth/login/ -- unsupported operand type(s) for %=: 'NoneType' and 'dict'
（根据another section in the official docs，错误对象只是一个字典。）
我也尝试了this，如this question中所述，但它也会出现同样的错误：
{% for field in form %}
<li>{{ field.errors|escape }}</li>
{% endfor %}
我错过了什么？
网址：
url(r"^login/$",
"auth_lifecycle.registration.view_login.login_maybe_remember",
{ "authentication_form": AuthenticationFormEnforceLength },
name="login"),
view_login.py
from auth_lifecycle.models import PASSWORD_MIN_LEN, PASSWORD_MAX_LEN
from auth_lifecycle.models import USERNAME_MIN_LEN, USERNAME_MAX_LEN
from django import forms #NOT django.contrib.auth.forms
from django.contrib.auth.forms import AuthenticationForm
from django.contrib.auth.views import login
from django.utils.translation import ugettext, ugettext_lazy as _
def login_maybe_remember(request, *args, **kwargs):
"""
Login with remember-me functionality and length checking. If the
remember-me checkbox is checked, the session is remembered for
SESSION_COOKIE_AGE seconds. If unchecked, the session expires at
browser close.
- https://docs.djangoproject.com/en/1.7/ref/settings/#std:setting-SESSION_COOKIE_AGE
- https://docs.djangoproject.com/en/1.7/topics/http/sessions/#django.contrib.sessions.backends.base.SessionBase.set_expiry
- https://docs.djangoproject.com/en/1.7/topics/http/sessions/#django.contrib.sessions.backends.base.SessionBase.get_expire_at_browser_close
"""
if request.method == 'POST' and not request.POST.get('remember', None):
#This is a login attempt and the checkbox is not checked.
request.session.set_expiry(0)
context = {}
context["USERNAME_MIN_LEN"] = USERNAME_MIN_LEN
context["USERNAME_MAX_LEN"] = USERNAME_MAX_LEN
context["PASSWORD_MIN_LEN"] = PASSWORD_MIN_LEN
context["PASSWORD_MAX_LEN"] = PASSWORD_MAX_LEN
kwargs["extra_context"] = context
return login(request, *args, **kwargs)
def get_min_max_incl_err_msg(min_int, max_int):
"""A basic error message for inclusive string length."""
"Must be between " + str(min_int) + " and " + str(max_int) + " characters, inclusive."
view_login.py继续：
username_min_max_len_err_msg = get_min_max_incl_err_msg(USERNAME_MIN_LEN, USERNAME_MAX_LEN)
pwd_min_max_len_err_msg = get_min_max_incl_err_msg(PASSWORD_MIN_LEN, PASSWORD_MAX_LEN)
class AuthenticationFormEnforceLength(AuthenticationForm):
"""
An `AuthenticationForm` that enforces min/max lengths.
- https://docs.djangoproject.com/en/1.7/_modules/django/contrib/auth/forms/#AuthenticationForm
Pass this into the login form via the `authentication_form` parameter.
- https://docs.djangoproject.com/en/1.7/topics/auth/default/#django.contrib.auth.views.login
Which is done in `registration/urls.py`.
"""
username = forms.CharField(min_length=USERNAME_MIN_LEN,
max_length=USERNAME_MAX_LEN,
error_messages={
'min_length': username_min_max_len_err_msg,
'max_length': username_min_max_len_err_msg })
password = forms.CharField(label=_("Password"), widget=forms.PasswordInput,
min_length=PASSWORD_MIN_LEN,
max_length=PASSWORD_MAX_LEN,
error_messages={
'min_length': pwd_min_max_len_err_msg,
'max_length': pwd_min_max_len_err_msg })
整个模板：
{% load i18n %} {# For the "trans" tag #}
{% load staticfiles %}{# References the static directory. #}
<!DOCTYPE html> {# Use with "{% static 'color_ajax_like.js' %}" #}
<html lang="en">
<HTML><HEAD>
<TITLE>Login</TITLE>
<!-- The following line makes this page pleasant to view on any device. -->
<meta name="viewport" content="width=device-width" />
</HEAD>
<BODY>
<H1>Login</H1>
{% if form.errors %}
{% for error in form.non_field_errors %}
{{error.msg}}
{% endfor %}
{% endif %}
<form method="post" id="loginForm" action="{% url 'login' %}">
{% csrf_token %}
<table>
<tr>
<td>{{ form.username.label_tag }}</td>
<td>{{ form.username }}</td>
</tr>
<tr>
<td>{{ form.password.label_tag }}</td>
<td>{{ form.password }}</td>
</tr>
</table>
<label><input name="remember" type="checkbox">{% trans "Remember me" %}</label>
<input type="submit" value="login" />
<input type="hidden" name="next" value="{% url 'main_page' %}" />
</form>
<P>{% trans "...I forgot my password..., ...Create a new account..." %}</P>
<p><i><a href="{% url 'main_page' %}">View the main page without logging in.</a></i></p>
<script language="JavaScript">
/*
Before our JavaScript can be imported, the following variables need
to be set from some Django variables. While these values could be
hard-coded here, into the JavaScript, this allows the configuration
to be centrally located.
These four values come from auth_lifecycle.models and are required
by validate_login_user_pass.js.
*/
var minUserLen = {{ USERNAME_MIN_LEN }}; //USERNAME_MIN_LEN
var maxUserLen = {{ USERNAME_MAX_LEN }}; //USERNAME_MAX_LEN
var minPassLen = {{ PASSWORD_MIN_LEN }}; //PASSWORD_MIN_LEN
var maxPassLen = {{ PASSWORD_MAX_LEN }}; //PASSWORD_MAX_LEN
document.getElementById("id_username").focus();
</script>
<script src="http://code.jquery.com/jquery-1.11.1.min.js"></script>
<script src="http://ajax.aspnetcdn.com/ajax/jquery.validate/1.13.0/jquery.validate.min.js"></script>
<script type='text/javascript' src="{% static 'js/validate_login_user_pass.js' %}"></script>
</BODY></HTML>
答案 0 :(得分：3)
form.errors是一本字典。您可以使用.items访问密钥（字段名称或__all__）和值（错误消息）：
{% for error_field, error_message in form.errors.items %}
{{ error_field|striptags }}: {{ error_message|striptags }}
{% endfor %}