Question

我将教师的CharField更改为ManyToManyField，现在我的UserMessage和EmailMessage已损坏，

模型如下：

class UserMessage(models.Model):
    user = models.ManyToManyField(User,related_name="recipent")
    send_user = models.ForeignKey(Use,null=True, blank=True, on_delete=models.SET_NULL, related_name="sender")
    message = models.CharField(max_length=500)
    test_name =models.CharField(max_length=800, default='', blank=True)
    test_date = models.DateField(default=datetime.now)
    test_time = models.TimeField(default=datetime.now)

    `# when teacher is not ManyToManyField, the EmailMessage of body works well with test.teacher.user`
    teacher = models.ManyToManyField(User, related_name="+")

test.teacher.username用于CharField，如何定义ManyToManyField？

body="Name of test：" + test.name  + "，Date ：" + str(test.date) + "，Time：" + str(test.time) + ", Teachers：" + test.teacher.username

以及如下所示的UserMessage的部分views.py（不是完整代码），UserMessage的功能运行良好，但是我想知道如何将form.cleaned_data['teacher'].username更改为ManyToManyFiled吗？我的意思是不是form.cleaned_data['teacher.set()']或其他任何东西，非常感谢您的任何建议。

user_message.test_name = form.cleaned_data['name']
user_message.teacher = form.cleaned_data['teacher'].username
user_message.test_time = form.cleaned_data['time']
user_message.test_date = form.cleaned_data['date']

Answer 1

要设置外键而不是其字段之一时，必须分配User实例。假设老师是一个用户对象，您可以使用类似的

for user_teacher in form.cleaned_data['teacher']:
    user_message.teacher.add(user_teacher)

如果您没有传递用户实例（仅说一个用户名），您将不得不以某种方式选择相关的教师，然后添加m2m关系，例如

user_teacher = get_object_or_404(get_user_model(), username=form.cleaned_data['teacher'])
user_message.teacher.add(user_teacher)

在您的用户名唯一的情况下可以使用。

如何使用m2m字段，字符串+ manytomanyfield制作form.cleaned_data []？-Django

1 个答案: