python - django admin - 选择反向外键关系(不是创建，我想添加可用)

Question

假设我有一个模型 School 和另一个模型 Student。

class Student(models.Model):
   school = models.ForeignKey(School)
   name = models.CharField(max_length=100)

在管理员中单击学校时，会出现一个新页面，显示学校模型字段和值。

我还想在该页面本身中选择已经可用的学生列表。

Inlines 不同，它们允许创建和编辑属于该学校的新记录(学生)。但我不想那样，假设已经有很多可用的学生记录。我应该能够在该学校模型页面的管理中选择它们。

Answer 1

class SchoolAdminForm(forms.ModelForm):
    students = forms.ModelMultipleChoiceField(
        queryset=Student.objects.all(),
        widget=FilteredSelectMultiple(verbose_name='students', is_stacked=False))

    class Meta:
        model = School
        fields = ['your_school_fields_go_here']

    def __init__(self, *args, **kwargs):
        super(SchoolAdminForm, self).__init__(*args, **kwargs)
        if self.instance:
            # fill initial related values
            self.fields['students'].initial = self.instance.student_set.all()

class SchoolAdmin(admin.ModelAdmin):
   form = SchoolAdminForm

   def save_model(self, request, obj, form, change):
       super().save_model(request, obj, form, change)
       original_students = set(obj.student_set.values_list("id", flat=True))
       current_students = set(map(lambda x: x.id, form.cleaned_data['students']))
       if original_students != current_students:
           add_to_school = current_students - original_students
           Student.objects.filter(id__in=add_to_school).update(school_id=obj.id)
           remove_from_school = original_students - current_students
           Student.objects.filter(id__in=remove_from_school).update(school_id=None)