Enum.HasFlag, why no Enum.SetFlag?

Question

I have to build an extension method for each flag type I declare, like so:

public static EventMessageScope SetFlag(this EventMessageScope flags, 
    EventMe         


        

Answer 1

I've done something that works for me and that's very simple...

    public static T SetFlag(this Enum value, T flag, bool set)
    {
        Type underlyingType = Enum.GetUnderlyingType(value.GetType());

        // note: AsInt mean: math integer vs enum (not the c# int type)
        dynamic valueAsInt = Convert.ChangeType(value, underlyingType);
        dynamic flagAsInt = Convert.ChangeType(flag, underlyingType);
        if (set)
        {
            valueAsInt |= flagAsInt;
        }
        else
        {
            valueAsInt &= ~flagAsInt;
        }

        return (T)valueAsInt;
    }

Usage:

    var fa = FileAttributes.Normal;
    fa = fa.SetFlag(FileAttributes.Hidden, true);