C# FlagAttriute 的小妙招

FlagAttriute ，指示可将枚举视为位域（即一组标志）。

官网中文解说：https://docs.microsoft.com/zh-cn/dotnet/api/system.flagsattribute?redirectedfrom=MSDN&view=netframework-4.7.2

以下是对应的demo,可以利用该特性，将业务场景中的角色设定为：1，2，4，8 这种按位操作，再判断是否包含该角色~

 1  public class EnumDemo
 2     {
 3         public static void Test()
 4         { 
 5             DirectionEnumType type = (DirectionEnumType)13;
 6 
 7             //可以用来判断是否存在right值
 8             bool IsExistRigth = ((type & DirectionEnumType.Right) == DirectionEnumType.Right);
 9 
10             Console.WriteLine(type);
11 
12             Console.WriteLine(IsExistRigth);
13             Console.WriteLine(1 << 5); //2的5次方  32
14 
15              //有对应值的会输出 int - string 数据，没有值的，则输出 int -int数据
16             for (int val = 0; val <= 16; val++)
17                 Console.WriteLine("{0,3} - {1:G}", val, (SingleHue)val);
18 
19             Console.WriteLine("--------------------------------");
20 
21 
22             //有值的，或者有对应的组合值的，会输出int -string数据，否则输出 int-int 数据
23             for (int val = 0; val <= 16; val++)
24                 Console.WriteLine("{0,3} - {1:G}", val, (MultiHue)val);
25 
26             /*
27 Top, Bottom, Left
28 False
29 32
30   0 - None
31   1 - Black
32   2 - Red
33   3 - 3
34   4 - Green
35   5 - 5
36   6 - 6
37   7 - 7
38   8 - Blue
39   9 - 9
40  10 - 10
41  11 - 11
42  12 - 12
43  13 - 13
44  14 - 14
45  15 - 15
46  16 - 16
47  --------------------------------
48   0 - None
49   1 - Black
50   2 - Red
51   3 - Black, Red
52   4 - Green
53   5 - Black, Green
54   6 - Red, Green
55   7 - Black, Red, Green
56   8 - Blue
57   9 - Black, Blue
58  10 - Red, Blue
59  11 - Black, Red, Blue
60  12 - Green, Blue
61  13 - Black, Green, Blue
62  14 - Red, Green, Blue
63  15 - Black, Red, Green, Blue
64  16 - 16
65              */
66         }

 1    [Flags]
 2     public enum DirectionEnumType
 3     {
 4         Top = 1,
 5         Right = 2,
 6         Bottom = 4,
 7         Left = 8,
 8     }
 9 
10     enum SingleHue : short
11     {
12         None = 0,
13         Black = 1,
14         Red = 2,
15         Green = 4,
16         Blue = 8
17     };
18 
19     // Define an Enum with FlagsAttribute.
20     [FlagsAttribute]
21     enum MultiHue : short
22     {
23         None = 0,
24         Black = 1,
25         Red = 2,
26         Green = 4,
27         Blue = 8
28     };

C# FlagAttriute 的 小妙招

C# FlagAttriute 的小妙招