如何在 Django 模型中使用枚举作为选择字段 [英] How to use enums as a choice field in django model

问题描述

我有一个模型类，我希望其中的两个字段作为选择字段，因此为了填充这些选择，我使用了下面列出的枚举

I have a model class of which I want two fields to be a choice fields, so to populate those choices I am using an enum as listed below

#models.py
class Transaction(models.Model):
    trasaction_status = models.CharField(max_length=255, choices=TransactionStatus.choices())
    transaction_type = models.CharField(max_length=255, choices=TransactionType.choices())

#enums.py
class TransactionType(Enum):

    IN = "IN",
    OUT = "OUT"

    @classmethod
    def choices(cls):
        print(tuple((i.name, i.value) for i in cls))
        return tuple((i.name, i.value) for i in cls)

class TransactionStatus(Enum):

    INITIATED = "INITIATED",
    PENDING = "PENDING",
    COMPLETED = "COMPLETED",
    FAILED = "FAILED"
    ERROR = "ERROR"

    @classmethod
    def choices(cls):
        print(tuple((i.name, i.value) for i in cls))
        return tuple((i.name, i.value) for i in cls)

但是，当我尝试通过管理员访问此模型时，出现以下错误:

However, when I am trying to access this model through admin I am getting the following error :

Django Version: 1.11
Exception Type: ValueError
Exception Value:    
too many values to unpack (expected 2)

我关注了两篇描述如何使用枚举的文章:

I followed two articles that described how to use enums:

• https://hackernoon.com/using-enum-as-model-field-choice-in-django-92d8b97aaa63
• https://blog.richard.do/2014/02/18/how-to-use-enums-for-django-field-choices/

推荐答案

对于 Django 2.x 及更低版本:

For Django 2.x and lower:

您可以通过设置各种选项来定义 Enum 这里:

You define an Enum by setting the various options as documented here:

class TransactionStatus(Enum):

    INITIATED = "INITIATED"
    PENDING = "PENDING"
    COMPLETED = "COMPLETED"
    FAILED = "FAILED"
    ERROR = "ERROR"

注意没有逗号！这允许您稍后在代码中引用 TransactionStatus.ERROR 或 TransactionStatus.PENDING.

Note there are no commas! This allows you later in your code to refer to TransactionStatus.ERROR or TransactionStatus.PENDING.

您的其余代码是正确的.您可以通过创建 option.name、option.value 的元组来获得 choices.

The rest of your code is correct. You get the choices by creating tuples of option.name, option.value.

更新:对于 Django 3.x 及更高版本，使用内置类型 TextChoices、IntegerChoices 和 Choices 如此处所述.这样您就不必自己构建 choices 元组.

UPDATE: For Django 3.x and higher, use the built-in types TextChoices, IntegerChoices and Choices as described here. That way you don't have to construct the choices tuple yourself.

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