Django:在管理页面上显示反向ForeignKey查找,作为只读列表？

Question

我想在Django管理页面上显示反向ForeignKey查找,并将其设置为只读,作为轻量级字符串列表.

执行此操作的标准方法似乎是使用内联管理字段,但我不希望它是可编辑的,因此我想知道是否有更轻量级的方法来执行此操作.

这些是我的领域:

class Book: 
  title = models.TextField(blank=True)
  author = models.ForeignKey(Author, on_delete=models.PROTECT)

class Author: 
  name = models.TextField(blank=True)

在作者的管理员更改/删除页面上,我想显示其图书的只读列表.

我可以用a来做到这一点admin.StackedInline,但是将它设为只读是非常麻烦的:

class BooksInline(admin.StackedInline):
  model = Book
  fields = ('title',)
  readonly_fields = ('title',)

  def has_add_permission(request, obj):
    return False

  def has_delete_permission(request, obj, self):
    return False

结果列表占用了页面上的大量空间,因为设计期望它都可以编辑.

是否有更简单的方法来制作只读列表？

Answer 1

我不喜欢在模型中使用仅管理逻辑的想法,如果我不需要,我不喜欢使用模板的想法,所以我在管理员中实现了这一点.

from django.contrib import admin

class AuthorAdmin(admin.ModelAdmin):
    readonly_fields = ('books_list')
    fields = ('name', 'books_list')

    def books_list(self, obj):
        books = Book.objects.filter(author=obj)
        if books.count() == 0:
            return '(None)'
        output = ', '.join([unicode(book) for book in books])
        return output
    books_list.short_description = 'Book(s)'

对于奖励积分,我们可以将每本书链接到该书的更改页面.

from django.contrib import admin
from django.core import urlresolvers
from django.utils.html import format_html

class AuthorAdmin(admin.ModelAdmin):
    readonly_fields = ('books_list')
    fields = ('name', 'books_list')

    def books_list(self, obj):
        books = Book.objects.filter(author=obj)
        if books.count() == 0:
            return '(None)'
        book_links = []
        for book in books:
            change_url = urlresolvers.reverse('admin:myapp_book_change', args=(book.id,))
            book_links.append('<a href="%s">%s</a>' % (change_url, unicode(book))
        return format_html(', '.join(book_links))
    books_list.allow_tags = True
    books_list.short_description = 'Book(s)'

双重奖励,您可以将其封装到一个函数中,这样您每次要在Admin中显示反向外键对象列表时都不必重写此逻辑:

from django.contrib import admin
from django.core import urlresolvers
from django.utils.html import format_html

def reverse_foreignkey_change_links(model, get_instances, description=None, get_link_html=None, empty_text='(None)'):
    if not description:
        description = model.__name__ + '(s)'

    def model_change_link_function(_, obj):
        instances = get_instances(obj)
        if instances.count() == 0:
            return empty_text
        output = ''
        links = []
        for instance in instances:
            change_url = urlresolvers.reverse('admin:%s_change' % model._meta.db_table, args=(instance.id,))
            links.append('<a href="%s">%s</a>' % (change_url, unicode(instance))
        return format_html(', '.join(links))

    model_change_link_function.short_description = description
    model_change_link_function.allow_tags = True
    return model_change_link_function

class AuthorAdmin(admin.ModelAdmin):
    readonly_fields = ('books_list')
    fields = ('name', 'books_list')

    def books_list = reverse_foreignkey_change_links(Book, lambda obj: Book.objects.filter(author=obj))

Answer 2

我将使用django 文档中提到的类方法，并使用此处文档中描述的 _set 相关反向查找。

列表结果是只读的，因此无需在管理员中进行检查。

// models.py
class Book: 
  title = models.TextField(blank=True)
  author = models.ForeignKey(Author, on_delete=models.PROTECT)

class Author: 
  name = models.TextField(blank=True)

  def get_author_books(self):
      cur_books = self.book_set.all()
      books = [b.title for b in cur_books]
      return books

  get_author_books.short_description = "Author's Books"


// admin.py
class BooksInline(admin.StackedInline):
  model = Book
  fields = ('title','get_author_books')