Dart如何获得“价值”一个枚举 [英] Dart How to get the "value" of an enum

问题描述

在Dart中提供枚举之前，我编写了一些麻烦且难以维护的代码来模拟枚举，现在想简化它。我需要以字符串形式获取枚举的值，例如可以用Java完成但不能。

Before enums were available in Dart I wrote some cumbersome and hard to maintain code to simulate enums and now want to simplify it. I need to get the value of the enum as a string such as can be done with Java but cannot.

例如，很少的测试代码片段在其中返回 day.MONDAY每种情况下我想要的是'MONDAY'

For instance little test code snippet returns 'day.MONDAY' in each case when what I want is 'MONDAY"

enum day {MONDAY, TUESDAY}
print( 'Today is $day.MONDAY');
print( 'Today is $day.MONDAY.toString()');

我是否纠正为仅获取'MONDAY'，我需要解析字符串？

Am I correct that to get just 'MONDAY' I will need to parse the string?

推荐答案

遗憾的是，您正确地认为toString方法返回 day.MONDAY ，而不是更有用的 MONDAY 。
您可以通过以下方式获取字符串的其余部分：

Sadly, you are correct that the toString method returns "day.MONDAY", and not the more useful "MONDAY". You can get the rest of the string as:

day theDay = day.MONDAY;      
print(theDay.toString().substring(theDay.toString().indexOf('.') + 1));

诚然，这很方便。

如果要迭代所有值，可以使用 day.values ：

If you want to iterate all the values, you can do it using day.values:

for (day theDay in day.values) {
  print(theDay);
}

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