C＃枚举不喜欢这个工作。然而，你可以很轻松地实现自己的固定的值：

C# enums don't work well like this. However, you can implement your own "fixed set of values" fairly easily:

public sealed class Foo
{
    public static readonly Foo FirstValue = new Foo(...);
    public static readonly Foo SecondValue = new Foo(...);

    private Foo(...)
    {
    }

    // Add methods here
}

碰巧的是，其中一个例子，我得到了，这是非常相似你的 - 的 DateTimeFieldType 在野田佳彦时间。有时你甚至可能要进行启封类，但保留私有构造 - 它允许你创建子类的只为嵌套类的。 。非常方便的限制继承

As it happens, one example I've got of this is remarkably similar to yours - DateTimeFieldType in Noda Time. Sometimes you might even want to make the class unsealed, but keep the private constructor - which allows you to create subclasses only as nested classes. Very handy for restricting inheritance.

缺点是，你不能使用开关：（

The downside is that you can't use switch :(