C＃int到枚举转换 [英] C# int to enum conversion

问题描述

可能重复：

在C＃中将int int枚举到

Possible Duplicate:
Cast int to enum in C#

如果我有以下代码：

enum foo : int
{
    option1 = 1,
    option2,
    ...
}

private foo convertIntToFoo(int value)
{
    // Convert int to respective Foo value or throw exception
}

转换代码是什么样的？

推荐答案

只要将您的int转换为Foo就可以了：

It's fine just to cast your int to Foo:

int i = 1;
Foo f = (Foo)i;

如果您尝试转换未定义的值，它仍然可以工作。可能来自这个的唯一的伤害是你以后如何使用这个值。

If you try to cast a value that's not defined it will still work. The only harm that may come from this is in how you use the value later on.

如果你真的想确保你的值在枚举中定义，你可以使用Enum.IsDefined：

If you really want to make sure your value is defined in the enum, you can use Enum.IsDefined:

int i = 1;
if (Enum.IsDefined(typeof(Foo), i))
{
    Foo f = (Foo)i;
}
else
{
   // Throw exception, etc.
}

但是，使用IsDefined的成本不仅仅是投射。你使用的取决于你的实施。您可能会考虑限制用户输入，或使用枚举时处理默认情况。

However, using IsDefined costs more than just casting. Which you use depends on your implemenation. You might consider restricting user input, or handling a default case when you use the enum.

另请注意，您不必指定您的枚举从int继承;这是默认行为。

Also note that you don't have to specify that your enum inherits from int; this is the default behavior.

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