python - 使用 Django 定义 ManyToManyField 的顺序

Question

有没有办法通过 ManyToManyField 定义相关对象的顺序？

例子:

• ArticleContainer1 按此顺序包含:
  第1条、第2条、第3条、第6条

• ArticleContainer2 按此顺序包含:
  第 3 条、第 2 条、第 1 条、第 4 条

• ArticleContainer3 按此顺序包含:
  第五条

这是我的类(class):

class Article(models.Model):    
    title = models.CharField(max_length=200)

class ArticleContainer(models.Model):
   contents = models.ManyToManyField(Article, blank=True, null=True)

Answer 1

这是我的一个示例，一个将人员组织到部门中并按部门排序的网站。它与您的问题的概念相同，但模型不同。本例使用多对多直通表。

class Department(models.Model):
    slug = models.SlugField(
        verbose_name    = _(u'Slug'),
        help_text           = _(u'Uri identifier for this department.'),
        max_length=255
    )
    name = models.CharField(
        verbose_name    = _(u'Department Name'),
        help_text           = _(u'The department\'s name.'),
        max_length      = 255
    )
    description = models.TextField(
        verbose_name    = _(u'Description'),
        help_text           = _(u'Department\'s description')
    )
    people = models.ManyToManyField(
        Person,
        through             = 'DepartmentPeople',
        related_name    = 'people',
        verbose_name    = _(u'People'),
        help_text           = _(u'People in this Department')
    )
    order_by = models.IntegerField(
        verbose_name    = _(u'Ordering Weight'), 
        help_text           = _(u'This item\'s weight within a list.'),
        max_length      = 255
    )

    class Meta:
        verbose_name = _(u"Department")
        verbose_name_plural = _(u"Departments")
        ordering = ['order_by',]

    def people_list(self):
        return [dp.person for dp in DepartmentPeople.objects.filter(department=self).order_by('order')]

    def __unicode__(self):
        return self.name        

以及直通模型:

class DepartmentPeople(models.Model):
    person = models.ForeignKey(
        Person,
        verbose_name    = _(u'Person'),
        help_text           = _(u'Person is a member of this deparment.'),
    )
    department = models.ForeignKey(
        Department,
        verbose_name    = _(u'Department'),
        help_text           = _(u'Pseron is a member of this department.'),
    )       
    order = models.IntegerField(
        verbose_name    = _(u'Order'),
        help_text           = _(u'What order to display this person within the department.'),
        max_length      = 255
    )

    class Meta:
        verbose_name = _(u"Department Person")
        verbose_name_plural = _(u"Department People")
        ordering = ['order',]

    def __unicode__(self):
        return self.person.first_name + " " + self.person.last_name + " is a member of " + self.department.name + (" in position %d" % self.order)

还有管理员:

class DepartmentPeopleInline(admin.TabularInline):
    model = DepartmentPeople
    extra = 1

class DepartmentAdmin(admin.ModelAdmin):
    inlines = (DepartmentPeopleInline,)

admin.site.register(Person, PersonAdmin)
admin.site.register(Department, DepartmentAdmin)

评论请求:

注意:以下是我的 PersonAdmin，但对于这个例子来说它不必要的复杂。你可以通过一个简单的

class PersonAdmin(admin.ModelAdmin) :
    pass

但这是我在我的应用程序中使用的:

class PersonForm(forms.ModelForm):
    abstract = forms.CharField(
        widget=TinyMCE(attrs={'cols': 80, 'rows': 30})
    )

    class Meta:
        model = Person

class PersonAdmin(reversion.VersionAdmin):
    form = PersonForm
    # The Form Fieldsets
    fieldsets = [
        (
            None,
            {
                'fields'    : [('first_name', 'last_name', 'post_nominal', ), 'slug', 'title', 'headshot', 'large_photo', ('email', 'phone', ), 'abstract']
            },
        )
    ]

    # Prepopulated fields
    prepopulated_fields = {'slug': ('first_name', 'last_name', 'post_nominal', )}

    # Fields that are readonly
    #readonly_fields = ('slug', )

    def formfield_for_dbfield(self, db_field, **kwargs):
        if db_field.name == 'headshot':
            request = kwargs.pop("request", None)
            kwargs['widget'] = AdminImageWidget
            return db_field.formfield(**kwargs)
        return super(PersonAdmin, self).formfield_for_dbfield(db_field, **kwargs)