Django 详细视图查询 - 按外键对象 textchoices 字段过滤答案

【问题标题】：Django Detail view query - filter by foreign key objects textchoices fieldDjango 详细视图查询 - 按外键对象 textchoices 字段过滤
【发布时间】：2020-03-06 12:13:30
【问题描述】：

我有以下 2 个模型 - ToDoList 和 Tasks。 Tasks 具有模型 ToDoList 的外键。在我的 Detailview 中，我只想显示已发布的任务 (status="published")。

我试图覆盖视图的获取上下文数据。这行得通。但它根本没有在 Detailview 中显示任何任务实例，即使我将例如 1 个任务设置为“已发布”。

我也尝试在模板中做过滤条件。我想这是不可能的？我或多或少地确定过滤条件必须出现在查询集中。

class ToDoList(TimeStamp):


    class STATUS(models.TextChoices): 
        PUBLISHED = "published", "Published" 
        TRASH = "trash", "Trash"
        WORKINGDRAFT = "workingdraft", "Workingdraft" 


    headline = models.CharField(max_length=200)
    author = models.ForeignKey(get_user_model(), on_delete=models.CASCADE)
    status = models.CharField("Status", max_length=20, choices=STATUS.choices, default=STATUS.PUBLISHED)



    def __str__(self):
        return self.headline

    def get_absolute_url(self):
        return reverse('notepad:todo_detail', args=[str(self.id)])


class Tasks(TimeStamp):

    class STATUS(models.TextChoices): 
        PUBLISHED = "published", "Published" 
        TRASH = "trash", "Trash"
        WORKINGDRAFT = "workingdraft", "Workingdraft" 


    todos = models.CharField(max_length=250)
    todolist = models.ForeignKey(ToDoList, on_delete=models.CASCADE, related_name='tasks')
    status = models.CharField("Status", max_length=20, choices=STATUS.choices, default=STATUS.PUBLISHED)


    def __str__(self):
        return self.todos

views.py

from django.shortcuts import render

# Create your views here.
from django.http import HttpResponseRedirect
from django.forms.models import inlineformset_factory
from django.views.generic import ListView, DetailView, TemplateView
from django.views.generic.edit import CreateView
from django.urls import reverse
from django.urls import reverse_lazy

from .models import ToDoList, Tasks
from .forms import ToDoListForm

class ToDoDetailView(DetailView):
    model = ToDoList
    template_name = 'notepad/notepad_detail.html'

    def get_context_data(self,**kwargs):
        context = super(ToDoDetailView,self).get_context_data(**kwargs)
       context['tasks_published'] = self.object.tasks.filter(status="published")
        return context    

    def get_object(self):
        object = super(ToDoDetailView, self).get_object()
        object.num_tasks = object.tasks.all().count()
        return object

模板

<!-- templates/books/book_detail.html -->
{% extends 'base.html' %}

{% block title %}{{ object.headline }}{% endblock title %}

{% block content %}
<div class="book-detail">
<h2><a href="">{{ object.headline }}</a></h2> 
<p>Author: {{ object.author }}</p> 
<p>Created at: {{ object.created }}</p>

<p>Total Tasks: {{ object.num_tasks }}</p>



<div>
    <h3>Tasks</h3> <ul>
    {% for todo in tasks_published %}
    <li>{{ todo.todos }}</li> 
    {% endfor %}
    </ul> </div>
</div>

<a class="btn btn-primary"
href="{% url 'notepad:todo_list' %}" role="button">
Back to ToDo List
</a> </p>
{% endblock content %}

任何帮助将不胜感激。非常感谢您的时间和支持。

【问题讨论】：

标签： django django-views django-templates

【解决方案1】：

请尝试：

def get_context_data(self,**kwargs):
    context = super(ToDoDetailView,self).get_context_data(**kwargs)
    context['tasks_published'] = self.object.tasks.filter(status=STATUS.PUBLISHED)
    return context

因为在您的代码中，您将拥有 ToDoList 实例而不是任务的列表。而在 DetailView() 中，您需要查看当前 TodoList 的已发布任务，对吧？

【讨论】：

非常感谢。这给了我以下错误：未定义名称“状态”。但是“self.object.tasks”是我错过的。正确的查询是：context['tasks_published'] = self.object.tasks.filter(status="published")。我编辑我的问题。
尝试在视图中导入状态

【解决方案2】：

尝试在 CharField 中将选择元组更改为我给元组

#define_tuple
PUBLISHED = (
    ('published','Published'),
    ('trash','Trash'),
    ('workingdraft','Workingdraft'),
)

class ToDoList(TimeStamp):
    headline = models.CharField(max_length=200)
    author = models.ForeignKey(get_user_model(), on_delete=models.CASCADE)
    #change in following line 
    status = models.CharField("Status", max_length=20, choices=PUBLISHED, default='published') #here change

    def __str__(self):
        return self.headline

在这两个模型中试用并检查它是否完美工作或不让我知道

【讨论】：