How to change enum definition without impacting clients using it in C#

Question

I have the following enum defined. I have used underscores as this enum is used in logging and i don't want to incur the overhead of reflection by using custom attribute.We use very heavy logging. Now requirement is to change "LoginFailed_InvalidAttempt1" to "LoginFailed Attempt1". If i change this enum, i will have to change its value across application. I can replace underscore by a space inside logging SP. Is there any way by which i can change this without affecting whole application.Please suggest.

public enum ActionType
{
    None,
    Created,
    Modified,
    Activated,
    Inactivated,
    Deleted,
    Login,
    Logout,
    ChangePassword,
    ResetPassword,
    InvalidPassword,
    LoginFailed_LockedAccount,
    LoginFailed_InActiveAccount,
    LoginFailed_ExpiredAccount,
    ForgotPassword,
    LoginFailed_LockedAccount_InvalidAttempts,
    LoginFailed_InvalidAttempt1,
    LoginFailed_InvalidAttempt2,
    LoginFailed_InvalidAttempt3,
    ForgotPassword_InvalidAttempt1,
    ForgotPassword_InvalidAttempt2,
    ForgotPassword_InvalidAttempt3,
    SessionTimeOut,
    ForgotPassword_LockedAccount,
    LockedAccount,
    ReLogin,
    ChangePassword_Due_To_Expiration,
    ChangePassword_AutoExpired

}

Answer 1

The best way to do it will be with a Description attribute. I understand that you don't use reflection, but you can always cache the result so it only happens once?

Add the description attribute:

[Description("LoginFailed Attempt1")]
LoginFailed_InvalidAttempt1

Then when displaying the text value of the enum, you can get the description out using the following bit of code:

private static Dictionary<Type, Dictionary<Enum, string>> enumMaps = null;

public static string GetDescription(Enum value)
{
    Type eType = value.GetType();
    if (enumMaps == null)
    {
        enumMaps = new Dictionary<Type, Dictionary<Enum, string>> ();
    }
    Dictionary<Enum, string> map;
    if (enumMaps.ContainsKey(eType))
    {
        map = enumMaps[eType];
    }
    else
    {
        map = new Dictionary<Enum, string>();
        foreach (Enum e in Enum.GetValues(eType))
        {
            FieldInfo fi = eType.GetField(e.ToString());
            DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(
                typeof(DescriptionAttribute), false);
            map[e] = (attributes.Length > 0) ? attributes[0].Description : e.ToString();
        }
        enumMaps[eType] = map;
    }
    return map[value];
}

As you can see from the code above, the reflection is only done once. Any subsequent calls on the same Enum value will return the result from a Dictionary which is lightning fast.