Python 我应该如何解决Django中这个奇怪的主键错误？

我有一个Django待办事项列表应用程序。在该应用程序中，有一个页面提供了有关任务的所有详细信息，如子任务和注释等。该页面的url类似于“/todo/task name”。出于安全原因，我希望通过任务的pk。此外，如果我在数据库中检查一个任务及其pk和标题，那么这将允许用户拥有多个同名任务。但是，一旦我通过了带有URL的pk，我就会面临子任务和注释的奇怪问题。这是处理任务页面的my view函数：

def todo_detail(request, title):
    try:
        todo = ToDo.objects.get(title=title, creator=request.user)
    except:
        return render(request, "ToDo/restrict_access.html")

    subtasks = SubTask.objects.filter(parent_task=todo)

    try:
        note = Notes.objects.get(parent_task=todo)
    except:
        note = Notes()

    if request.method == "POST":
        note_form = ToDoNotesForm(request.POST)
        subtask_form = SubTaskForm(request.POST)
        due_form = DueDateForm(request.POST)

        if note_form.is_valid():
            task_notes = note_form.cleaned_data.get("task_notes")

            new_note = Notes(content=task_notes)
            new_note.parent_task = todo
            new_note.save()

            todo.has_notes = True
            todo.save()

            messages.success(request, "Your notes are saved")

            return HttpResponseRedirect(request.META.get('HTTP_REFERER', '/'))

        elif subtask_form.is_valid():
            subtask_title = subtask_form.cleaned_data.get("sub_task")

            subtask = SubTask(title=subtask_title)
            subtask.parent_task = todo

            subtask.parent_task.num_of_subtasks += 1
            subtask.parent_task.save()

            subtask.save()

            messages.success(request, "Subtask added")

            return HttpResponseRedirect(request.META.get('HTTP_REFERER', '/'))

        elif due_form.is_valid():
            days = due_form.cleaned_data.get("due_date").lower()

            if days == "today":
                days = 0
            elif days == "tomorrow":
                days = 1
            elif days == "next week":
                days = 7
            elif days == "yesterday":
                days = -1
            elif days == "last week":
                days = -7
            else:
                days = int(days)

            today = datetime.datetime.today()
            due_date = today + datetime.timedelta(days=days)

            todo.due_date = due_date
            todo.save()

            messages.success(request, "Due Date added to task")

            return HttpResponseRedirect(request.META.get('HTTP_REFERER', '/'))

    else:
        note_form = ToDoNotesForm()
        subtask_form = SubTaskForm()
        due_form = DueDateForm()

    context = {
        "todo": todo,
        "note_form": note_form,
        "note": note,
        "subtask_form": subtask_form,
        "subtasks": subtasks,
        "due_form": due_form,
        "title": todo.title,
        "percentage": percentage
    }

    return render(request, "ToDo/detailed_view.html", context=context)

在“详细信息”页面中，有用于选中、取消选中或编辑子任务或编辑注释的链接。在html页面中，我确保只通过编辑或检查视图功能的相应pk

There were some HTML code here that is not relevent

    {% if subtasks %}
        <br><br>
        <center style="font-size:27px; background-color: burlywood; color: 'black';">Subtasks for this task:</center>
        <br>
        <div style="padding-left: 4ch;">
            {% for subtask in subtasks %}
                <div class="content-section dark-mode-assist-section">
                    {% if not subtask.done %}
                        {% if request.user_agent.is_mobile %}
                            <li style="font-size: 23px;">
                                <a style="color:inherit; text-decoration: none;" href="{% url 'todo-edit-subtask' subtask.pk %}"> {{ subtask.title }} </a>
                                <br>
                                <button onclick="location.href='{% url 'todo-toggle-subtask' subtask.pk %}'" type="button" class="btn btn-outline-success">Check it off</button>
                                <button onclick="location.href='{% url 'delete-item' 'subtask' subtask.pk %}'" type="submit" class="btn btn-outline-danger">Delete</button> 
                            </li>
                        {% else %}
                            <li style="font-size: 23px;">
                                <a style="color:inherit; text-decoration: none;" href="{% url 'todo-edit-subtask' subtask.pk %}"> {{ subtask.title }} </a> 
                                <button onclick="location.href='{% url 'todo-toggle-subtask' subtask.pk %}'" style="float: right; size:3ch" type="button" class="btn btn-outline-success">Check it off</button> 
                                <button onclick="location.href='{% url 'delete-item' 'subtask' subtask.pk %}'" style="float: right; size:3ch" type="submit" class="btn btn-outline-danger">Delete</button> 
                            </li>
                        {% endif %}
                    {% else %}
                        {% if request.user_agent.is_mobile %}
                            <li style="font-size: 23px;">
                                <a style="color:inherit; text-decoration: line-through;" href="{% url 'todo-edit-subtask' subtask.pk %}"> {{ subtask.title }} </a>
                                <br>
                                <button onclick="location.href='{% url 'todo-toggle-subtask' subtask.pk %}'" type="button" class="btn btn-outline-success">Uncheck it </button> 
                                <button onclick="location.href='{% url 'delete-item' 'subtask' subtask.pk %}'" type="submit" class="btn btn-outline-danger">Delete</button> 
                            </li>
                        {% else %}
                            <li style="font-size: 23px;"><a class="control-subtask" style="color:inherit; text-decoration: line-through;" href="{% url 'todo-edit-subtask' subtask.pk %}"> {{ subtask.title }} </a> <button onclick="location.href='{% url 'todo-toggle-subtask' subtask.pk %}'" style="float: right; size:3ch" type="button" class="btn btn-outline-success">Uncheck it</button> <button onclick="location.href='{% url 'delete-item' 'subtask' subtask.pk %}'" style="float: right; size:3ch" type="submit" class="btn btn-outline-danger">Delete</button> </li>
                        {% endif %}
                    {% endif %}
                </div>
            {% endfor %}
            {% if percentage != 0 %}
                <center style="font-size:23px; background-color: burlywood; color: 'black';">Your progress:</center>
                <center> <span style="font-size:10ch; color:lightseagreen">{{ percentage }}%</span></center>
            {% endif %}
        </div>
    {% endif %}

    {% if todo.has_notes %}
        <br>
        <center style="font-size:27px; background-color: burlywood; color: 'black';">Notes for this task:</center>
        <h3>
            <br>
            <div style="font-family:Candara">{{ note.content|linebreaks }}</div>
            <button class="btn btn-outline-danger" type="submit" onclick="location.href='{% url 'delete-item' 'notes' note.pk %}'">Delete notes</button>
            <button class="btn btn-outline-info" type="submit" onclick="location.href='{% url 'todo-edit-notes' note.pk %}'">Edit notes</button>
        </h3>
        <p>
            <br>
            Notes added on: <b>{{ note.date_added|date:"F d, Y" }}</b>
            <br>

            {% if note.date_edited != note.date_added %}
                Notes edited on: <b>{{ note.date_edited|date:"F d, Y" }}</b>
            {% endif %}
        </p>

    {% else %}

        <br>
        <form method="POST" name={{ note.pk }} >
            {% csrf_token %}
            <fieldset class="form-group dark-mode-assist">
                <legend class="border-bottom mb-4">Add notes</legend>
                {{ note_form|crispy }}
                <input type="hidden" name="title" value={{ note.pk }}>
            </fieldset>
            <div class="form-group">
                <button class="btn btn-outline-info" type="submit">Add</button>
            </div>
        </form>

    {% endif %}
</div>

{% endblock content %}

---

所以很明显，如果没有找到待办事项，我应该在访问详细信息页面时首先出错。但我可以进入详细信息页面。问题是当我想检查子任务时，他们说找不到ToDo，但实际上我正在检查子任务not ToDo。

因为第一个查询与数据库不匹配。你犯了这个错误。因此，您可以使用

ToDo.DoesNotExist

跟踪异常，如下所示：

    try:
        todo = ToDo.objects.get(title=title, creator=request.user)
    except ToDo.DoesNotExist:
        return render(request, "ToDo/restrict_access.html")

---

您的查看功能

toggle\u子任务

没有路由到，因为

todo\u detail

正在路由到第一个

从中的django文档：

Django按顺序在每个URL模式中运行，并在与请求的URL匹配的第一个模式处停止，与

路径信息匹配

在

urls.py

文件中，您可以对URL进行结构化，使最具体的URL（如

/todo/toggle_subtask/

）位于最不具体的URL（如

/todo/

）之前：

从django.url导入路径
从…起导入视图#无论从何处导入'views.py'
URL模式=[
#/todo/toggle\u子任务//
路径（'/todo/toggle_子任务//'，views.toggle_子任务），
#/待办事项//
路径（'/todo/'，视图.todo_详细信息），
]

我收到一个错误，因为DoesNotExist不是ToDo的属性。第二，我想把问题弄清楚。我已使用“切换子任务”功能更新了问题，以帮助您更好地理解。请检查一下。请包括相关的

url.py

你是绝对正确的人！！我正要把我的URL.py包括进去，我看到你已经回答了。在我的url.py中，我看到“/todo/”位于“/todo/toggle_subtask/”之前。我已经改变了他们的命令，现在一切都很顺利。再次感谢您，说实话，我今天学到了一些关于Django的新知识，我相信这对我将来也会有很大的帮助。：）

    try:
        todo = ToDo.objects.get(title=title, creator=request.user)
    except ToDo.DoesNotExist:
        return render(request, "ToDo/restrict_access.html")