How to limit choice field options based on another choice field in django admin

Question

I have the following models:

class Category(models.Model):
    name = models.CharField(max_length=40)

class Item(models.Model):
    name = models.CharField(         


        

Answer 1

There is django-smart-selects:

If you have the following model:

class Location(models.Model)
    continent = models.ForeignKey(Continent)
    country = models.ForeignKey(Country)
    area = models.ForeignKey(Area)
    city = models.CharField(max_length=50)
    street = models.CharField(max_length=100)

And you want that if you select a continent only the countries are available that are located on this continent and the same for areas you can do the following:

from smart_selects.db_fields import ChainedForeignKey 

class Location(models.Model)
    continent = models.ForeignKey(Continent)
    country = ChainedForeignKey(
        Country, 
        chained_field="continent",
        chained_model_field="continent", 
        show_all=False, 
        auto_choose=True
    )
    area = ChainedForeignKey(Area, chained_field="country", chained_model_field="country")
    city = models.CharField(max_length=50)
    street = models.CharField(max_length=100)