带有flags属性的枚举

Question

我有枚举：

    [Flags, Serializable,]
    public enum WeekDays {
        Sunday = 1,
        Monday = 2,
        Tuesday = 4,
        Wednesday = 8,
        Thursday = 16,
        Friday = 32,
        Saturday = 64,
        WeekendDays = Sunday | Saturday,
        WorkDays = Monday | Tuesday | Wednesday | Thursday | Friday,
        EveryDay = WeekendDays | WorkDays
    }

而且，我在一个包含WeekDays枚举值的类中有属性WeekDays ：

public int WeekDays {get; set;}

例如， WorkDays包含62（从星期一到星期五）。
如何检查当前的WeekDays属性是否包含当天？

Answer 1

Enum具有方法HasFlag用于确定是否在当前实例中设置了一个或多个位字段。

Answer 2

使用按位运算符&查看某个值是否为集合的一部分：

var today = WeekDays.Thursday;
var workdays = WeekDays.WorkDays;

if((today & workdays) == today) {
    // today is a workday
}

if((today & WeekDays.Friday) == today) {
    // it's friday
}

Answer 3

使用& ：

    [Flags, Serializable,]
    public enum WeekDays
    {
        Sunday = 1,
        Monday = 2,
        Tuesday = 4,
        Wednesday = 8,
        Thursday = 16,
        Friday = 32,
        Saturday = 64,
        WeekendDays = Sunday | Saturday,
        WorkDays = Monday | Tuesday | Wednesday | Thursday | Friday,
        EveryDay = WeekendDays | WorkDays
    }

    public static WeekDays Days { get; set; }

    private static void Main(string[] args)
    {
        WeekDays today = WeekDays.Sunday;

        Days = WeekDays.WorkDays;

        if ((Days & today) == today)
        {
            Console.WriteLine("Today is included in Days");
        }

        Console.ReadKey();
    }

Answer 4

WeekDays weekDayValue = .... ;
var today = Enum.Parse(typeof(WeekDays),DateTime.Now.DayOfWeek.ToString())
bool matches = ( weekDayValue & today ) == today;

Answer 5

做：

int r = (int)(WeekDays.WorkDays & WeekDays.Sunday)
if (r !=0)
  you have it.

Answer 6

您只需要使用按位布尔逻辑来执行此操作。 如果你要说

WeekDays.Tuesday & WeekDays.WorkDays

那么布尔逻辑将返回4（因为4和62 = 4）。

基本上＆表示对于每个位位置，如果两者都是1，则返回该数字。 所以你只需要检查它是否> 0。

要以您当前的格式获取今天，那么您需要做一些数学...

(int)DateTime.Now.DayOfWeek将返回从0（星期日）到6（星期六）的星期几。

我们需要映射这些以匹配您的范围。 幸运的是，使用Math.Pow很容易。

int today = Math.Pow(2,(int)DateTime.Now.DayOfWeek);
if (today&WeekDays.WorkDays>0)
    isWorkDay = true;
else
    isWorkDay = false;

Answer 7

获取所有枚举名称和值，然后执行“和”计算以测试WeekDays是否包含当天