Python 为什么在尝试访问HttpRequest.POST['；choice'；]值时出现类型错误？如何解决此错误？

我最近一直在学习django教程，我被卡住了。在使用post方法提交表单后，我尝试使用.get（）方法获取所选的_choice模型对象，但得到一个TypeError:无法解包不可编辑的ModelBase对象错误

以下是视图

from django.shortcuts import render, get_object_or_404

from django.http import HttpResponseRedirect
from django.urls import reverse
from .models import Question, Choice

def vote(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    try:
        selected_choice = question.choice_set.get(Question, pk=request.POST['choice'])
    except (KeyError, Choice.DoesNotExist):
        return render(request, 'polls/detail.html', {'question': question, 'error_message': 'Please select a choice and vote'})
    else:
        selected_choice.no_of_votes += 1
        selected_choice.save()
        return HttpResponseRedirect(reverse('polls:result', args=(question.id,)))

def result(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    return render(request, 'polls/result.html', {'question': question})

以下是模板

from django.shortcuts import render, get_object_or_404

from django.http import HttpResponseRedirect
from django.urls import reverse
from .models import Question, Choice

def vote(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    try:
        selected_choice = question.choice_set.get(Question, pk=request.POST['choice'])
    except (KeyError, Choice.DoesNotExist):
        return render(request, 'polls/detail.html', {'question': question, 'error_message': 'Please select a choice and vote'})
    else:
        selected_choice.no_of_votes += 1
        selected_choice.save()
        return HttpResponseRedirect(reverse('polls:result', args=(question.id,)))

def result(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    return render(request, 'polls/result.html', {'question': question})

detail.html

{% block content_main %}

<h2>{{question.question_text}}</h2>
{% if error_message %} <strong>{{error_message}}</strong><br><br> {% endif %}
<form action="{% url 'polls:vote' question.id %}" method="post">
{% csrf_token %}
{% for choice in question.choice_set.all %}
    <input type="radio" name="choice" id="choice{{forloop.counter}}" value="{{choice.id}}" style="margin-left: 20px;">
    <label for="choice{{forloop.counter}}" style="font-size: 20px;">{{choice.choice_text}}</label><br><br>
{% endfor %} <br>
    <input type="submit" value="vote" style="margin-left: 30px; font-size: 20px;">
</form>

{% endblock %}

在终端中，

>[14/Nov/2019 00:52:14] "GET / HTTP/1.1" 404 2027 Not
> Found: /favicon.ico [14/Nov/2019 00:52:16] "GET /favicon.ico HTTP/1.1"
> 404 2078 [14/Nov/2019 00:52:24] "GET /polls/ HTTP/1.1" 200 447
> [14/Nov/2019 00:52:27] "GET /polls/1/ HTTP/1.1" 200 1145 Internal
> Server Error: /polls/1/vote Traceback (most recent call last):   File
> "C:\Users\Neeyat\PycharmProjects\DjangoApps\Polls\venv\lib\site-packages\django\core\handlers\exception.py",
> line 34, in inner
>     response = get_response(request)   File "C:\Users\Neeyat\PycharmProjects\DjangoApps\Polls\venv\lib\site-packages\django\core\handlers\base.py",
> line 115, in _get_response
>     response = self.process_exception_by_middleware(e, request)   File "C:\Users\Neeyat\PycharmProjects\DjangoApps\Polls\venv\lib\site-packages\django\core\handlers\base.py",
> line 113, in _get_response
>     response = wrapped_callback(request, *callback_args, **callback_kwargs)   File "C:\Users\Neeyat\PycharmProjects\DjangoApps\Polls\mysite\polls\views.py",
> line 28, in vote
>     selected_choice = question.choice_set.get(Question, pk=request.POST['choice'])   File
> "C:\Users\Neeyat\PycharmProjects\DjangoApps\Polls\venv\lib\site-packages\django\db\models\manager.py",
> line 82, in manager_method
>     return getattr(self.get_queryset(), name)(*args, **kwargs)   File "C:\Users\Neeyat\PycharmProjects\DjangoApps\Polls\venv\lib\site-packages\django\db\models\query.py",
> line 399, in get
>     clone = self.filter(*args, **kwargs)   File "C:\Users\Neeyat\PycharmProjects\DjangoApps\Polls\venv\lib\site-packages\django\db\models\query.py",
> line 892, in filter
>     return self._filter_or_exclude(False, *args, **kwargs)   File "C:\Users\Neeyat\PycharmProjects\DjangoApps\Polls\venv\lib\site-packages\django\db\models\query.py",
> line 910, in _filter_or_exclude
>     clone.query.add_q(Q(*args, **kwargs))   File "C:\Users\Neeyat\PycharmProjects\DjangoApps\Polls\venv\lib\site-packages\django\db\models\sql\query.py",
> line 1290, in add_q
>     clause, _ = self._add_q(q_object, self.used_aliases)   File "C:\Users\Neeyat\PycharmProjects\DjangoApps\Polls\venv\lib\site-packages\django\db\models\sql\query.py",
> line 1318, in _add_q
>     split_subq=split_subq, simple_col=simple_col,   File "C:\Users\Neeyat\PycharmProjects\DjangoApps\Polls\venv\lib\site-packages\django\db\models\sql\query.py",
> line 1187, in build_filter
>     arg, value = filter_expr TypeError: cannot unpack non-iterable ModelBase object [14/Nov/2019 00:52:30] "POST /polls/1/vote HTTP/1.1"
> 500 102541

---

我刚开始做后端web开发，我在任何地方都找不到解决方案。请帮我解决这个问题。提前谢谢。

您的

视图中有一点小错误。py

：

def vote(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    try:
        selected_choice = question.choice_set.get(pk=request.POST['choice']) # <-- here
    except (KeyError, Choice.DoesNotExist):
        return render(request, 'polls/detail.html', {'question': question, 'error_message': 'Please select a choice and vote'})
    else:
        selected_choice.no_of_votes += 1
        selected_choice.save()
        return HttpResponseRedirect(reverse('polls:result', args=(question.id,)))

def投票（请求，问题编号）：
问题=获取对象或404（问题，主键=问题id）
尝试：
所选内容=问题.choice\u集.get（pk=request.POST['choice']）#
def vote(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    try:
        selected_choice = question.choice_set.get(pk=request.POST['choice']) # <-- here
    except (KeyError, Choice.DoesNotExist):
        return render(request, 'polls/detail.html', {'question': question, 'error_message': 'Please select a choice and vote'})
    else:
        selected_choice.no_of_votes += 1
        selected_choice.save()
        return HttpResponseRedirect(reverse('polls:result', args=(question.id,)))