python-3.x - 根据先前的选择列表答案更改的 Django 选择列表

Question

我正在尝试制作一个动态的选择列表。也就是说，选择会根据先前的答案而改变。例如，如果country = ["USA", "Canada", "Mexico"]，然后单击“美国”，将生成一个包含 50 个美国州的列表，state = ["Alabama", "Alaska"]。我试图做一个 if 语句，但是，这似乎不起作用。我不确定最好的选择是什么。

class Property(models.Model):
    address = CharField(max_length = 200)
    city = CharField(max_length = 200)

    COUNTRY_LIST = [
        ("USA", "United States"),
        ("CAN", "Canada")
    ]
    country = CharField(max_length = 3, choices = COUNTRY_LIST)

    USA_STATE_LIST = [
        ("AL", "Alabama"),
        ("AK", "Alaska"),
        ("AZ", "Arizona")
    ]
    CAN_STATE_LIST = [
        ("AL", "Alberta"),
        ("BC", "British Columbia")
    ]
    state = CharField(max_length = 2, choices = ?)

标签： python-3.xdjango-models