如何为删除按钮修复Django表中的NoReverseMatch错误

问题描述

Python版本3.7.7和Django版本2.2.3。 Github上的代码 https://github.com/jcwill415/Stock_Market_Web_App

我想在表的最后一列中添加一个删除按钮。当代码不在表中时，它将删除表中的条目。但是当代码在表中时，我收到一个noreverseMatch错误，提示：

  noreverseMatch at /add_stock.html 
  Reverse for 'delete' with arguments '('',)' not found. 1 pattern(s) tried: ['delete/(?P<stock_id>[^/]+)$']

Request Method: GET
Request URL:    http://localhost:8000/add_stock.html
Django Version: 2.2.3
Exception Type: noreverseMatch
Exception Value:    
Reverse for 'delete' with arguments '('',)' not found. 1 pattern(s) tried: ['delete/(?P<stock_id>[^/]+)$']
Exception Location: C:\djangostock\venv\lib\site-packages\django\urls\resolvers.py in _reverse_with_prefix,line 668
Python Executable:  C:\djangostock\venv\Scripts\python.exe
Python Version: 3.7.7
Python Path:    
['C:\\Users\\JCW\\Desktop\\Stock_Market_Web_App-master\\stock','C:\\Users\\JCW\\AppData\\Local\\Programs\\Python\\python37-32\\python37.zip','C:\\Users\\JCW\\AppData\\Local\\Programs\\Python\\python37-32\\Lib','C:\\Users\\JCW\\AppData\\Local\\Programs\\Python\\python37-32\\DLLs','C:\\Program Files\\python37','C:\\djangostock\\venv','C:\\djangostock\\venv\\lib\\site-packages']

add_stock.html

<table class="table table-striped table-hover">

  <thead class="thead-dark">
    <tr>
      <th scope="col">TICKER</th>
      <th scope="col">COMPANY</th>
      <th scope="col">STK PRICE</th>
      <th scope="col">PREV CLOSE</th>
      <th scope="col">MARKET CAP</th>
      <th scope="col">VOLUME</th>
      <th scope="col">YTD CHG</th>
      <th scope="col">52 WK HIGH</th>
      <th scope="col">52 WK LOW</th>
      <th scope="col">REMOVE STK</th>
    </tr>
  </thead>
  <tbody>
{% if ticker %}
      
            {% for list_item in output %}
                <tr>
                    <th scope="row">{{ list_item.symbol }}</th>
                    <td>{{ list_item.companyName }}</td>
                    <td>${{ list_item.latestPrice }}</td/>
                    <td>${{ list_item.prevIoUsClose }}</td>
                    <td>${{ list_item.marketCap }}</td>
                    <td>{{ list_item.latestVolume }}</td>
                    <td>{{ list_item.ytdChange }}</td>
                    <td>${{ list_item.week52High }}</td>
                    <td>${{ list_item.week52Low }}</td>
                    <td><a href="{% url 'delete' item.id %}" class="btn btn-outline-danger btn-small">Delete {{ item }}</a></br></td>          
        </tr>
        
            {% endfor %}
        
  </tbody>
</table>
{% endif %}

{% for item in ticker %}
    <a href="{% url 'delete' item.id %}" class="btn btn-outline-danger btn-small">Delete {{ item }}</a> &nbsp;
{% endfor %}

views.py

def delete(request,stock_id):
    item = Stock.objects.get(pk=stock_id) # call database by primary key for id #
    item.delete()
    messages.success(request,("Stock Has Been Deleted From Portfolio!"))
    return redirect('add_stock')

urls.py

from django.urls import path
from . import views

urlpatterns = [
    path('',views.home,name="home"),path('about.html',views.about,name="about"),path('add_stock.html',views.add_stock,name="add_stock"),path('delete/<stock_id>',views.delete,name="delete"),path('news.html',views.news,name="news"),]

我尝试过的事情 我已经尝试过使用for循环：

{% for item in ticker %}
   <td><a href="{% url 'delete' item.id %}" class="btn btn-outline-danger btn-small">Delete {{ item }}</a></td>
{% endfor %}

但是它遍历所有行情自动收录器，因此每行表中的所有条目都有删除按钮。如果不使用for循环，则会出现noreverseMatch错误。我知道有解决此问题的方法，但我一直在努力并进行了两个多月的搜索。

我也尝试了while循环，但无法正常工作。我尝试将一个删除表单添加到具有对views.py文件的相应请求的add_stock.html文件中。

我尝试过但仍然无法解决的链接：

• How to fix Django "NoReverseMatch" Error
• What is a NoReverseMatch error,and how do I fix it?
• NoReverseMatch: Reverse for 'deleted' with no arguments not found. - Django
• how to add delete button in each row of my table?

ments-not-found-django

解决方法

您在2个不同的地方使用delete。首先，您引用了错误的项目：

{% for list_item in output %}
   ...
   {% url 'delete' item.id %} 

应该是

{% url 'delete' list_item.id %}

在第二个中，这是正确的：

{% for item in ticker %}
   <a href="{% url 'delete' item.id %}"

此外，在许多情况下，delete是保留字。我认为情况并非如此，但仍然是个坏习惯。随处更改为delete_stock：

<a href="{% url 'delete_stock' list_item.id %}" ...>

def delete_stock(request,stock_id=None):

path('delete_stock/<stock_id>',views.delete_stock,name="delete_stock"),

stock_id是整数还是字符串？要找出答案，请在add_stock()的循环内打印：

api = json.loads(api_request.content)
print(api)
output.append(api)

此外，库存ID将作为字符串出现在url中，因此，如果它是整数，请执行以下操作：

item = Stock.objects.get(pk=int(stock_id))

或使用：

path('delete_stock/<int:stock_id>',

其他网址有效吗？

奖金提示：

您的网址中无需包含.html。看起来过时了。更好的形式是：

urlpatterns = [
    path('',views.home,name="home"),path('about',views.about,name="about"),path('add_stock',views.add_stock,name="add_stock"),path('delete_stock/<int:stock_id>',path('news',views.news,name="news"),]