我是编码新手，尤其是使用Django的新手。我想为我和其他学生建立一个小的“论坛”，并且效果很好。
我一次又一次遇到一个错误：
Exception Type: NoReverseMatch
Exception Value: Reverse for 'thread-create' with
arguments '('',)' not found. 1 pattern(s) tried: ['forum/(?P<pk>[0-9]+)/add/$']
我可以使用函数而不是基于类的View来解决它，但是我怀疑那是应该这样做的。
在使用类视图时，我感到自己缺少一些非常重要的东西。
如果有人可以帮助我，我真的很感激：-）
这是无效的链接：
{% url 'user-posts' thread.author.username %}
更重要的是：
{% url 'forum:thread-create' thread.id %}
使用类时还不起作用的是：
{% for thread in thema.thread_set %} (works with the functions)
（我只想查看绑定到特定主题的线程。这对于函数也很好用）。
您可能还会问为什么我不仅仅使用基于函数的视图：
代码：
# models.py
from django.db import models
from django.urls import reverse
from PIL import Image
from django.utils import timezone
from django.contrib.auth.models import User
class Thema(models.Model):
themengebiet = models.CharField(max_length=350)
beschreibung = models.TextField()
themen_logo = models.FileField(max_length=350, upload_to="logos", default='default.jpg')
erstellt_am = models.DateTimeField(default=timezone.now)
def __str__(self):
return self.themengebiet
def save(self, *args, **kwargs):
super().save(*args, **kwargs)
img = Image.open(self.themen_logo.path)
if img.height > 300 or img.width > 300:
output_size = (300, 300)
img.thumbnail(output_size)
img.save(self.themen_logo.path)
class Thread(models.Model):
thema = models.ForeignKey(Thema, on_delete=models.CASCADE)
titel = models.CharField(max_length=350)
author = models.ForeignKey(User, on_delete=models.CASCADE, null=True, blank=True)
erstellt_am = models.DateTimeField(default=timezone.now)
thread_logo = models.ImageField(upload_to="logos", d efault='default.jpg')
def get_absolute_url(self):
return reverse('forum:thread-page', kwargs={'pk': self.thema.id})
def __str__(self):
return self.titel
class Posting(models.Model):
thread = models.ForeignKey(Thread, on_delete=models.CASCADE)
titel = models.CharField(max_length=350)
erstellt_am = models.DateTimeField(default=timezone.now)
author = models.ForeignKey(User, on_delete=models.CASCADE)
inhalt = models.TextField()
def __str__(self):
return self.titel
views.py
from django.views import generic
from django.views.generic import CreateView, UpdateView, DeleteView, ListView
from .models import Thema, Thread, Posting
from django.shortcuts import render, get_object_or_404
from django.urls import reverse_lazy
from django.contrib.auth.mixins import LoginRequiredMixin
from django.contrib.auth.decorators import login_required
from django.http import Http404
from django.core.paginator import Paginator
class ThemenView(ListView):
template_name = 'forum/posts_original.html'
context_object_name = 'all_themen'
def get_queryset(self):
return Thema.objects.all()
class ThemaCreate(CreateView):
model = Thema
fields = ['themengebiet', 'beschreibung', 'themen_logo']
success_url = "/forum/"
class ThreadCreate(CreateView):
model = Thread
fields = ['thema', 'titel', 'erstellt_am']
success_url = reverse_lazy('forum:posts_original')
def get_object(self):
return Thread.objects.get(pk=self.kwargs['pk'])
def form_valid(self, form):
form.instance.author = self.request.user
return super().form_valid(form)
class PostCreate(CreateView):
model = Posting
fields = ['thread', 'titel', 'inhalt', 'erstellt_am']
success_url = "/forum/"
def form_valid(self, form):
form.instance.author = self.request.user
return super().form_valid(form)
class ThreadView(ListView):
model = Thread
context_object_name = 'threads'
template_name = 'forum/thread.html'
success_url = reverse_lazy('forum:posts_original')
def get_object(self):
return Thread.objects.get(pk=self.kwargs['pk'])
class PostView(ListView):
model = Posting
context_object_name = 'posts'
template_name = 'forum/posts.html'
urls.py
from django.urls import path
from . import views
app_name = 'forum'
urlpatterns = [
# /forum/
path('', views.ThemenView.as_view(), name='posts_original'),
# forum/id/
path('<int:pk>/', views.ThreadView.as_view(), name='thread-page'),
# forum/thread/add
#path('<int:pk>/add/', views.thread_create, name='thread-create'),
# forum/id//id
path('thread/<int:pk>/', views.PostView.as_view(), name='post-page'),
path('add/', views.ThemaCreate.as_view(), name='thema-create'),
path('<int:pk>/add/', views.ThreadCreate.as_view(), name='thread-create'),
path('thread/<int:pk>/add/', views.PostCreate.as_view(), name='post-create'),
]
'''
def thread(request, pk):
try:
thema = get_object_or_404(Thema, pk=pk)
except Thema.DoesNotExist:
raise Http404("Thema existitiert nicht")
return render(request, 'forum/thread.html', {'thema': thema})
def post(request, pk):
try:
thread = get_object_or_404(Thread, pk=pk)
except Thread.DoesNotExist:
raise Http404("Thema existitiert nicht!")
return render(request, 'forum/posts.html', {'thread': thread})
'''
{% extends "blog/base.html" %}
{{ threads }}
{% block content %}
<a href="{% url 'forum:posts_original' %}">Zurück zur Themenübersicht</a>
{% for thread in threads %}
<article class="media content-section">
<img class="rounded-circle article-img" src= "{{ thread.thread_logo.url }}">
<div class="media-body">
<div class="article-metadata">
<a class="mr-2" href="{% url 'user-posts' thread.author.username %}">{{ thread.author }}</a>
<small class="text-muted">{{ thread.erstellt_am|date:"d. F Y" }}</small>
</div>
<h2><a class="article-title" href=" {% url 'forum:post-page' thread.id %}">{{ thread.titel }}</a></h2>
<p class="article-content">Thema: {{ thread.thema }}</p>
</div>
</article>
{% endfor %}
<form action="{% url 'forum:thread-create' thread.id %}" method="post" enctype="multipart/form-data" style="display: inline;">
{% csrf_token %}
<a href="{% url 'forum:thread-create' thread.id %">Thread hinzufügen</a>
</form>
{% endif %}
{% endblock content %}