级联下拉的实现方式（如省市县）-1 Smart Selects方式

from django.db import models
from smart_selects.db_fields import (  ChainedForeignKey,    ChainedManyToManyField,    GroupedForeignKey,
)

class Continent(models.Model):
    name = models.CharField(max_length=255)
    def __str__(self):
        return "%s" % self.name

class Country(models.Model):
    continent = models.ForeignKey(Continent, on_delete=models.CASCADE)
    name = models.CharField(max_length=255)
    def __str__(self):
        return "%s" % self.name


class Location(models.Model):

    continent = models.ForeignKey(Continent, on_delete=models.CASCADE)
    country = ChainedForeignKey(
        "Country",
        chained_field="continent",
        chained_model_field="continent",
        show_all=False,
        auto_choose=True,
        null=True,
        blank=True
    )
    city = models.CharField(max_length=50)
    street = models.CharField(max_length=100)

class LocationForm(forms.ModelForm):
    class Meta:
        model = Location
        fields = '__all__'
    def clean(self):
        cleaned_data = super().clean()

{% extends 'appsmarts/base.html' %}
{% load crispy_forms_tags %}
{% load static %}

{% block content %}

<form action='.' method='POST'>{% csrf_token %}
    <script src="{% static 'js/jquery-3.3.1.min.js' %}"></script>
    <script src="{% static 'smart-selects/admin/js/bindfields.js' %}"></script>
    <script src="{% static 'smart-selects/admin/js/chainedfk.js' %}"></script>
    {{ form|crispy}}
    <input type='submit' value='Save' />
</form>

{% endblock %}