Question

I’m using a enum with flags attribute as a way of tracking status.

An example is the following:

Created = 1
Completed = 2
Dispatched = 4

Without writing anything too rigid (if check this, do that, if check that, do this) i want to be able to find the highest flag which has been set so in this example:

Item.Status = Status.Created | Status.Completed

the mythical method would return 2 – as completed is the flag set with the highest value.

GetMaxSetFlagValue(Item.Status) // returns 2

I’ve found questions which revolved around the actual enum, just not a value which uses flags. I’m fairly sure this could be achieved with Linq…?

Answer 1

Something like the following should work:

static int GetMaxSetFlagValue<T>(T flags) where T : struct
{
   int value = (int)Convert.ChangeType(flags, typeof(int));
   IEnumerable<int> setValues = Enum.GetValues(flags.GetType()).Cast<int>().Where(f => (f & value) == f);
   return setValues.Any() ? setValues.Max() : 0;
}

The method will fail if T is not an enum type, so a check should preferably be performed in the beginning of the method. Also it will not work for an enum with an underlying type larger than int (i.e. long).