adding django admin many-to-many widget

In the django admin documentation, it says the following:

By default, admin widgets for many-to-many relations will be displayed on whichever model contains the actual reference to the ManyToManyField.

Is there a way to get a similar widget to appear on the admin page for the other model, the one w开发者_如何学JAVAhere the relationship isn't defined?

There's a couple different ways to get the effect that you're after.

Here's one way, which will get you a similar (but not identical) effect, and probably requires the least coding. (Examples will use classes A and B, assuming that the former has the many to many relationship explicitly defined)

The quickest way: you can use an InlineModelAdmin object:

class AInline(admin.TabularInline):
    model = A

class BAdmin(admin.ModelAdmin):
    inlines = (AInline,)
admin.site.register(B, BAdmin)

If you want the exact effect of getting a <select multiple>, the way you can do it is to use a custom Form class, and assign it to BAdmin.form.