In Django Admin, I want to change how foreign keys are displayed in a Many-Many Relationship admin widget
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22-07-2019 - |
Question
I have a ManyToMany relationship:
class Book: title = models.CharField(...) isbn = models.CharField(...) def unicode(self): return self.title def ISBN(self): return self.isbn class Author: name = models.CharField(...) books = models.ManyToManyField(Book...)
In the admin interface for Author I get a multiple select list that uses the unicode display for books. I want to change the list in two ways:
1) Only for the admin interface I want to display the ISBN number, everywhere else I just print out a "Book" object I want the title displayed.
2) How could I use a better widget than MultipleSelectList for the ManyToMany. How could I specify to use a CheckBoxSelectList instead?
Solution
For 2), use this in your AuthorAdmin class:
raw_id_fields = ['books']
Check here: http://docs.djangoproject.com/en/dev/ref/contrib/admin/#ref-contrib-admin for instructions on creating a custom ModelAdmin class. I've thought about this a lot myself for my own Django project, and I think 1) would require modifying the admin template for viewing Author objects.
OTHER TIPS
To display the ISBN you could make a custom field like this:
class BooksField(forms.ModelMultipleChoiceField):
def label_from_instance(self, obj):
return obj.isbn
There's a CheckboxSelectMultiple for the ManyToManyField but it doesn't display correctly on the admin, so you could also write some css to fix that.
You need to create a form for the model, and use that in your admin class:
class AuthorForm(forms.ModelForm):
books = BooksField(Book.objects.all(), widget=forms.CheckboxSelectMultiple)
class Meta:
model = Author
class Media:
css = {
'all': ('booksfield.css',)
}
class AuthorAdmin(admin.ModelAdmin):
form = AuthorForm