枚举和常量.什么时候用哪个? [英] Enums and Constants. Which to use when?

问题描述

我在阅读枚举时发现它们与声明常量非常相似.我怎么知道什么时候使用常量而不是枚举，反之亦然.使用枚举有哪些优点?

I was doing some reading on enums and find them very similar to declaring constants. How would I know when to use a constant rather than an enum or vice versa. What are some of the advantages of using enums?

推荐答案

当您想定义某个值的范围时，请使用枚举.颜色是一个明显的例子，如:

Use enums when you want to define a range of values that something can be. Colour is an obvious example like:

public enum Colour
{
    White,
    Red,
    Blue
}

或者可能是一组可能的事情，例如:(我从这里偷来的例子，因为我很懒)

Or maybe a set of possible things like: (Example I stole from here as I'm lazy)

[FlagsAttribute]
enum DistributedChannel
{
  None = 0,
  Transacted = 1,
  Queued = 2,
  Encrypted = 4,
  Persisted = 16,
  FaultTolerant = Transacted | Queued | Persisted
}

常量应该用于单个值，例如 PI.没有 PI 值的范围，只有 PI.

Constants should be for a single value, like PI. There isn't a range of PI values, there is just PI.

其他需要考虑的点是:

• a:常量不一定表示常量之间的关系，而枚举表示某些东西可以是枚举定义的集合之一.
• b:定义的枚举在用作参数时可以帮助您进行类型检查.常量只是值，因此它们不提供任何额外的语义信息.

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