c# - Can I avoid casting an enum value when I try to use or return it?

Question

If I have the following enum:

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

Can I avoid casting when I return, like this:

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

If not, why isn't an enum value treated as an int by default?

Answer 1

enums are supposed to be type safe. I think they didn't make them implicitly castable to discourage other uses. Although the framework allows you to assign a constant value to them, you should reconsider your intent. If you primarily use the enum for storing constant values, consider using a static class:

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

That lets you do this.

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

EDIT

When you do want to provide values to an enum is when you want to combine them. See the below example:

[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
}

This enum can then be consumed by using bitwise math. See the below example for some applications.

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;
    }
}