正确使用Enum的FlagsAttribute
FlagsAttribute 标志枚举对象的值可以包括多个枚举成员，每个成员代表枚举值中的一个位域
使用步骤
- 添加标记
[Flags] - 用 2 的幂（即 1、2、4、8 等）定义枚举常量,比如0,1,1<<1,1<<2,1<<3
- 标记
[Flags]的枚举项之间可以进行NOT,OR,AND,XOR操作
例子1
[Flags]
public enum DaysOfWeek
{
Sunday = 1,
Monday = 1 << 1,
Tuesday = 1 << 2,
Wednesday = 1 << 3,
Thursday = 1 << 4,
Friday = 1 << 5,
Saturday = 1 << 6,
}
var workDays1 = DaysOfWeek.Monday | DaysOfWeek.Tuesday |
DaysOfWeek.Thursday | DaysOfWeek.Thursday | DaysOfWeek.Friday;
var workDays2 = DaysOfWeek.Friday | DaysOfWeek.Saturday
| DaysOfWeek.Sunday;
~workDays1
//DaysOfWeek.Saturday,DaysOfWeek.Sunday
workDays1 ^workDays2
//DaysOfWeek.Monday, DaysOfWeek.Tuesday,DaysOfWeek.Thursday,
//DaysOfWeek.Thursday,DaysOfWeek.Saturday, DaysOfWeek.Sunday
workDays1&DaysOfWeek.Monday //DaysOfWeek.Monday
例子2
//判断是否包含某项
//.net4.0新增
if (workDays1.HasFlag(DaysOfWeek.Monday))
{
//...
}
//4.0以前的版本
if ((workDays1 & DaysOfWeek.Monday) == DaysOfWeek.Monday)
{
//...
}