c# - 我可以在尝试使用或返回枚举值时避免强制转换它吗？

Question

如果我有以下枚举:

public enum ReturnValue{
    Success = 0,
    FailReason1 = 1,
    FailReason2 = 2
    //Etc...
}

我可以在返回时避免转换吗，像这样:

public static int main(string[] args){
    return (int)ReturnValue.Success;
}

如果不是，为什么默认情况下不将枚举值视为 int？

Answer 1

枚举应该是类型安全的。我认为他们并没有让它们隐式转换以阻止其他用途。尽管框架允许您为它们分配一个常量值，但您应该重新考虑您的意图。如果您主要使用枚举来存储常量值，请考虑使用静态类:

public static class ReturnValue
{
    public const int Success = 0;
    public const int FailReason1 = 1;
    public const int FailReason2 = 2;
    //Etc...
}

这让你可以做到这一点。

public static int main(string[] args){
    return ReturnValue.Success;
}

编辑

当您确实想要为枚举提供值时，就是您想要组合它们的时候。请参阅以下示例:

[Flags] // indicates bitwise operations occur on this enum
public enum DaysOfWeek : byte // byte type to limit size
{
    Sunday = 1,
    Monday = 2,
    Tuesday = 4,
    Wednesday = 8,
    Thursday = 16,
    Friday = 32,
    Saturday = 64,
    Weekend = Sunday | Saturday,
    Weekdays = Monday | Tuesday | Wednesday | Thursday | Friday
}

然后可以使用按位数学来使用此枚举。有关某些应用程序，请参见下面的示例。

public static class DaysOfWeekEvaluator
{
    public static bool IsWeekends(DaysOfWeek days)
    {
        return (days & DaysOfWeek.Weekend) == DaysOfWeek.Weekend;
    }

    public static bool IsAllWeekdays(DaysOfWeek days)
    {
        return (days & DaysOfWeek.Weekdays) == DaysOfWeek.Weekdays;
    }

    public static bool HasWeekdays(DaysOfWeek days)
    {
        return ((int) (days & DaysOfWeek.Weekdays)) > 0;
    }

    public static bool HasWeekendDays(DaysOfWeek days)
    {
        return ((int) (days & DaysOfWeek.Weekend)) > 0;
    }
}