如何仅在detailviewDjango的ManytoManyfield上设置order_by？

编程问答 2022-07-04

问题描述

我有2个模型Class和Student。 Class mdel中的一个字段与ManytoManyField具有Student关系。我想在模板中使用first_name订购manytomanyfield。我该怎么办？

models.py 

class Student(models.Model):
    user = models.OnetoOneField(CustomUser,on_delete=models.CASCADE,primary_key=True)
    first_name = models.CharField(max_length=100)


class Class(models.Model):
    student = models.ManyToManyField(Student)
    subject = models.CharField(max_length=150,unique=True)
    # many other fields

views.py 

class Class_detailView(LoginrequiredMixin,DetailView):
    login_url = '/'
    model = Class
    template_name = "attendance/content/teacher/class_detail.html

模板

<div class="row ml-auto mr-auto">
  <h6>{{ object.subject }}</h6>
  {% for student in object.student.all %}
    <h6 id="class-detail-text" class="mt-2">
      {{student.first_name}} <-- want to order here
    </h6>
  {% endfor %}
</div>

现在名称呈现如下：

Freaky  Albon  Bucky

我希望它这样订购：

Albon   Bucky  Freaky

解决方法

在模型元中设置ordering 

class Student(models.Model):
    user = models.OneToOneField(CustomUser,on_delete=models.CASCADE,primary_key=True)
    first_name = models.CharField(max_length=100)

    class Meta:
        ordering = ('first_name',)
,

您可以直接覆盖视图的 model.compile(loss=ctc_loss_func(y_true,y_pred,input_length,label_length),optimizer='adam',metrics=['acc']) 属性。如果您始终一直希望在您访问它时进行订购，那么您也可以使用queryset模型的Meta属性。

Student

请参阅from django.db.models import Prefetch class Class_detailView(LoginRequiredMixin,DetailView): queryset = Class.objects.prefetch_related(Prefetch('student',queryset=Student.objects.order_by('name')) login_url = '/' model = Class template_name = "attendance/content/teacher/class_detail.html 上的文档： https://docs.djangoproject.com/en/3.1/ref/models/querysets/#prefetch-related

顺便说一句，prefetch_related通常是复数形式，因此请考虑将其更改为ManyToManyField。

djangodjangomanytomanyfieldpython