{Programming} & Life

Every now and then I find myself needing to set multiple values to an enum object and test this later on, synonymously I usually find myself also scouring the net on the best practice on how to set, access and test these enum flags

So today I thought I would post a definitive reference I found on the net..

Specify flag-annotated enum:

[Flags]
public enum Column
{
None = 0,
Priority = 1 << 0,
Customer = 1 << 1,
Contract = 1 << 2,
Description = 1 << 3,
Tech = 1 << 4,
Created = 1 << 5,
Scheduled = 1 << 6,
DueDate = 1 << 7,
All = int.MaxValue
};

The [Flags] attribute allows you to do this:

Column MyColumns = Column.Customer | Column.Contract;

To check if contains flag:

if ((MyColumns & Column.Customer) != 0)

To check if has flag or higher:

if (MyColumns >= Column.Customer)

To check if has flag or lower:

if (MyColumns <= Column.Customer)

To set a flag:

MyColumns |= Column.Tech;

To clear a flag:

MyColumns &= ~Column.Tech;

To toggle (flip) a flag:

MyColumns ^= Column.Contract;

To clear all flags:

MyColumns = Column.None;

To set all flags:

MyColumns = Column.All;

To set all flags EXCEPT one or more:

MyColumns = Column.All ^ Column.Tech ^ Column.Status;

Credit to Jeremy Lundy for the comprehensive write up.