NoReverseMatch at - django polls应用教程

Question

当我试图加载一个页面时，我一直得到这样的结果：

NoReverseMatch at /polls/
Reverse for 'vote' with arguments '('',)' not found. 1 pattern(s) tried: ['polls/(?P<question_id>[0-9]+)/vote/$']

In template C:\Users\sarah\Desktop\django2\myproject\my_site\polls\templates\polls\index.html, error at line 20

第20行：

<form action="{% url 'polls:vote' question.id %}" method="post">

我是一个完全的初学者在django，css，html，...我一直在查看教程，将我的代码与教程中的代码参考进行比较，但我没有发现任何错误。

我的index.html：

{% load static %}

<link rel="stylesheet" type="text/css" href="{% static 'polls/style.css' %}">


{% if latest_question_list %}
    <ul>
    {% for question in latest_question_list %}
        <li><a href="{%url 'polls:detail' question.id %}/">{{ question.question_text }}</a></li>
    {% endfor %}
    </ul>
{% else %}
    <p>No polls are available.</p>
{% endif %}

<h1>{{ question.question_text }}</h1>

{% if error_message %}<p><strong>{{ error_message }}</strong></p>{% endif %}

<form action="{% url 'polls:vote' question.id %}" method="post">
{% csrf_token %}
{% for choice in question.choice_set.all %}
    <input type="radio" name="choice" id="choice{{ forloop.counter }}" value="{{ choice.id }}">
    <label for="choice{{ forloop.counter }}">{{ choice.choice_text }}</label><br>
{% endfor %}
<input type="submit" value="Vote">
</form>

Views.py中的投票函数：

def vote(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    try:
        selected_choice = question.choice_set.get(pk=request.POST['choice'])
    except (KeyError, Choice.DoesNotExist):
        # Redisplay the question voting form.
        return render(request, 'polls/detail.html', {
            'question': question,
            'error_message': "You didn't select a choice.",
        })
    else:
        selected_choice.votes += 1
        selected_choice.save()
        return HttpResponseRedirect(reverse('polls:results', args=(question.id,)))

urls.py：

from django.urls import path
from . import views


app_name = 'polls'
urlpatterns = [
    path('', views.IndexView.as_view(), name='index'),
    path('<int:pk>/', views.DetailView.as_view(), name='detail'),
    path('<int:pk>/results/', views.ResultsView.as_view(), name='results'),
    path('<int:question_id>/vote/', views.vote, name='vote'),

谢谢。

Answer 1

这里的主要原因是您将index.html与表单一起使用，您应该在polls/detail中使用该表单，这样您就可以通过pk访问question对象。现在，您正在尝试访问question的id属性，但question在index.html中未定义。

在polls/details.html中放置以下内容

<h1>{{ question.question_text }}</h1>
<form action="{% url 'polls:vote' question.id %}" method="post">
    {% csrf_token %}
    {% for choice in question.choice_set.all %}
        <input type="radio" name="choice" id="choice{{ forloop.counter }}" value="{{ choice.id }}">
        <label for="choice{{ forloop.counter }}">{{ choice.choice_text }}</label><br>
    {% endfor %}
    <input type="submit" value="Vote">
</form>

然后，导航到polls/1或您想要的任何question.id，然后尝试使用表单。