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django - 出现“无属性”错误时如何添加到 ManyToMany？

问题描述

使用表单，在第一次获得要添加的问题的查询集后，我试图将项目添加到对象的多对多字段questions中。Quiz我保存了 ModelForm，但是当我添加项目时，我得到了一个 AttributError：'function' object has no attribute 'questions'

以前，我能够使用模型中的保存方法创建一个包含 3 个随机问题的测验对象。但是，我看不到仅使用模型从特定查询集中添加 3 个问题的方法

视图.py

def choose(request, obj_id):
    """Get the id of the LearnObject of interest"""
    """Filter the questions and pick 3 random Qs"""
    my_qs = Question.objects.filter(learnobject_id=obj_id)
    my_qs = my_qs.order_by('?')[0:3]
    if request.method == 'POST':
        form = QuizForm(request.POST)
        if form.is_valid():
            new_quiz = form.save
            for item in my_qs:
                new_quiz.questions.add(item)
            new_quiz.save()
            return HttpResponseRedirect('/quizlet/quiz-list')
    else:
        form = QuizForm()  
    return render(request, 'quizlet/quiz_form.html', {'form': form})

和models.py

class LearnObject(models.Model):
    """model for the learning objective"""
    code = models.CharField(max_length=12)
    desc = models.TextField()

class Question(models.Model):
    """model for the questions."""
    name = models.CharField(max_length=12)
    learnobject = models.ForeignKey(
        LearnObject, on_delete=models.CASCADE,
        )
    q_text = models.TextField()
    answer = models.CharField(max_length=12)

class Quiz(models.Model):
    """quiz which will have three questions."""
    name = models.CharField(max_length=12)
    questions = models.ManyToManyField(Question)
    completed = models.DateTimeField(auto_now_add=True)
    my_answer = models.CharField(max_length=12)

class QuizForm(ModelForm):
    """test out form for many2many"""
    class Meta:
        model = Quiz
        fields = ['name', 'my_answer']

错误发生在行new_quiz.questions.add(item)。我不明白这一点，因为模型Quiz有一个字段questions，并且对象（我认为）已经在第一个创建new_quiz = form.save()

标签： djangomanytomanyfield

解决方案

错误在下一行：new_quiz = form.save，您缺少()，将其更改为new_quiz = form.save()。

如果不是，则将函数的引用保存form.save到new_quiz, 而不是函数返回的对象。

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