Django錯誤：未找到參數'（''，）'和關鍵字參數'{}'的'blog_detail_url'反向。 1模式嘗試：['博客/（？P <id> \\ d +）$']

Question

在我的博客上，我試圖創建一個URL尋呼系統，我可以通過ID鏈接到上一個和下一個帖子Post模型。現在，每次我試圖去一個博客網頁，我得到這個錯誤：

NoReverseMatch at /blog/2 
Reverse for 'blog_detail_url' with arguments '('',)' and keyword arguments '{}' not found. 1 pattern(s) tried: ['blog/(?P<id>\\d+)$'] 

views.py：

def blog_detail(request, id): 
    # post request from the url 
    return render(request, "BlogHome/pages/post.html") 
    post = Post.objects.get(id) 

    # Next Post 
    try: 
     Next_Post_id = (post.id + 1) 
     Next_Post = Post.objects.get(id=Next_Post_id) 
    except ObjectDoesNotExist: 
     Next_Post = None 

    # Previous Post 
    try: 
     Previous_Post_id = (post.id - 1) 
     Previous_Post = Post.objects.get(id=Previous_Post_id) 
    except ObjectDoesNotExist: 
     Previous_Post = None 

    context = {'post': post, 'Next_Post': Next_Post, 'Previous_Post': Previous_Post} 
    return render(request, "BlogHome/pages/post.html", context) 

urls.py：

urlpatterns = [ 
url(r'^$', views.blog_list), 
url(r'^(?P<id>\d+)$', views.blog_detail, name='blog_detail_url'), 
] 

post.html：

{% extends "BlogHome/includes/WELL.html" %} 

{% block content %} 
<script> 
document.title = "Pike Dzurny | {{post.title}}" 
</script> 

<div class="container-fluid text-center"> 

    <center> 

     <div class="well" id="WellPost"> 

      <div class="container-fluid"> 

       <h2 align="center" id="TitleText">{{post.title}}</h2> 
       <h3 align="center" id="BodyText">{{ post.date|date:"m-d"}}</h3> 
       <h3 align="left">{{ post.body|safe }}</h3> 

       {% if Next_Post is defined and Previous_Post is defined %} 
       <ul class="pager"> 
        <li class="previous"><a href="{% url 'blog:blog_detail_url' Post.id %}"><span 
          aria-hidden="true">&larr;</span> Older</a></li> 
        <li class="next "><a href="{% url 'blog:blog_detail_url' Next_Post.id %}">Newer <span 
          aria-hidden="true">&rarr;</span></a></li> 
        <h1>1</h1> 
       </ul> 

       {% elif Next_Post is defined %} 
       <ul class="pager"> 
        <li class="previous disabled"><a href=""><span aria-hidden="true">&larr;</span> Older</a></li> 
        <li class="next"><a href="{% url 'blog:blog_detail_url' Next_Post.id %}">Newer <span aria-hidden="true">&rarr;</span></a> 
        </li> 
       </ul> 
       <h1>2</h1> 

       {% elif Previous_Post is defined %} 
       <ul class="pager"> 
        <li class="previous"><a href="{% url 'blog:blog_detail_url' Post.id %}"><span aria-hidden="true">&larr;</span> 
         Older</a></li> 
        <li class="next disabled"><a href="">Newer <span aria-hidden="true">&rarr;</span></a></li> 
       </ul> 
       <h1>3</h1> 

       {% else %} 
       <ul class="pager"> 
        <li class="previous disabled"><a href="{% url 'blog:blog_detail_url' Post.id %}"><span aria-hidden="true">&larr;</span> Older</a></li> 
        <li class="next disabled"><a href="{% url 'blog:blog_detail_url' Next_Post.id %}">Newer <span aria-hidden="true">&rarr;</span></a></li> 
       </ul> 
       <h1>4</h1> 
       {% endif %} 


      </div> 
    </center> 
</div> 

{% endblock %} 

錯誤發生在post.html中的第22行（​​<li class="previous"><a href="{% url 'blog:blog_detail_url' Post.id %}"><span aria-hidden="true">&larr;</span> Older</a></li>）。我猜，我非常建立jinja2 href？

Answer 1

從

"{% url 'blog:blog_detail_url' Next_Post.id %}" 

更改鏈接到

"{% url 'blog:blog_detail_url' id=Next_Post.id %}" 

通知的id=。您的網址格式指定id作爲url kwarg。

此外，作爲一個經驗法則，你不應該用大寫字母命名你的變量。在Python中，使用小寫變量名是標準的，然後使用大寫名稱作爲類。當這一貫地完成時，它有助於使你的代碼更具可讀性。

編輯

這也似乎有點腥對我說：{% if Next_Post is defined and Previous_Post is defined %}什麼是defined？我沒有在上下文或其他地方看到它。我會這樣做：

{% if next_post %} 
    {# ... #} 
{% endif %}