标记枚举（flags）的使用
时间：2010-09-18 来源：四海清一
标记枚举是为标记相互包含而使用的，每个成员被赋给一个唯一的按位值。
用按位或运算符（|）来组合按位标记。用按位和运算符（&）来确定一个标记的存在。
从组合状态中去掉一个元素用& (~）。
示例代码：
1
using System;
2using System.Collections.Generic;
3using System.Text;
4
5namespace ConsoleApplication1
6
{
7
class Program
8
{
9 [Flags]
10 public enum Contribution
11 {
12 Pension=0x01,
13 ProfitSharing=0x02,
14 CreditBureau=0x04,
15 SavingsPlan=0x08,
16 All = Pension | ProfitSharing | CreditBureau | SavingsPlan
17
}
18 public class Employee
19 {
20 private Contribution prop_contributions;
21 public Contribution contributions
22 {
23 get { return prop_contributions; }
24 set { prop_contributions = value; }
25 }
26 }
27
28 public class Starter
29 {
30 public static void Main()
31 {
32 Employee bob = new Employee();
33 bob.contributions = Contribution.ProfitSharing | Contribution.CreditBureau;
34 if ((bob.contributions & Contribution.ProfitSharing) == Contribution.ProfitSharing)
35 {
36 Console.WriteLine("Bob enrolled in profit sharing");
37 Console.WriteLine(bob.contributions);
38 bob.contributions = bob.contributions & (~Contribution.ProfitSharing);
39 Console.WriteLine(bob.contributions);
40 }
41 }
42 }
43 }
44
}
using System;2
using System.Collections.Generic;3
using System.Text;4
5
namespace ConsoleApplication16
{7
class Program8
{9
[Flags]10
public enum Contribution11
{12
Pension=0x01,13
ProfitSharing=0x02,14
CreditBureau=0x04,15
SavingsPlan=0x08,16
All = Pension | ProfitSharing | CreditBureau | SavingsPlan17
}18
public class Employee19
{20
private Contribution prop_contributions;21
public Contribution contributions22
{23
get { return prop_contributions; }24
set { prop_contributions = value; }25
}26
}27
28
public class Starter29
{30
public static void Main()31
{32
Employee bob = new Employee();33
bob.contributions = Contribution.ProfitSharing | Contribution.CreditBureau;34
if ((bob.contributions & Contribution.ProfitSharing) == Contribution.ProfitSharing)35
{36
Console.WriteLine("Bob enrolled in profit sharing");37
Console.WriteLine(bob.contributions);38
bob.contributions = bob.contributions & (~Contribution.ProfitSharing);39
Console.WriteLine(bob.contributions);40
}41
}42
}43
}44
}
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