C#中枚举类型enum的使用

C#中枚举类型enum的使用

关于enum应用的总结（摘自 http://hi.baidu.com/yangzhiping/blog/item/9d841fd5a4309dc451da4baa.html）

 

1、关于enum的定义 enum Fabric { Cotton = 1, Silk = 2, Wool = 4, Rayon = 8, Other = 128 } 2、符号名和常数值的互相转换               Fabric fab = Fabric.Cotton;             int fabNum = (int)fab;//转换为常数值。必须使用强制转换。             Fabric fabString = (Fabric)1;//常数值转换成符号名。如果使用ToString()，则是 （（Fabric）1）.ToString()，注意必须有括号。             string fabType = fab.ToString();//显示符号名             string fabVal = fab.ToString (" D");//显示常数值   3、获得所有符号名的方法（具体参见Enum类）           public enum MyFamily         {             YANGZHIPING = 1,             GUANGUIQIN = 2,             YANGHAORAN = 4,             LIWEI = 8,             GUANGUIZHI = 16,             LISIWEN = 32,             LISIHUA = 64,         }               foreach (string s in Enum.GetNames(typeof(MyFamily)))             {                 Console.WriteLine(s);             }   4、将枚举作为位标志来处理 根据下面的两个例子，粗略地说，一方面，设置标志[Flags]或者[FlagsAttribute]，则表明要将符号名列举出来；另一方面，可以通过强制转换，将数字转换为 符号名。说不准确。看下面的例子体会吧。注意：           例一：           Fabric fab = Fabric.Cotton | Fabric.Rayon | Fabric.Silk;           Console.WriteLine("MyFabric = {0}", fab);//输出：Fabric.Cotton | Fabric.Rayon | Fabric.Silk; 例二： class FlagsAttributeDemo {     // Define an Enum without FlagsAttribute.     enum SingleHue : short     {         Black = 0,         Red = 1,         Green = 2,         Blue = 4     };     // Define an Enum with FlagsAttribute.     [FlagsAttribute]     enum MultiHue : short     {         Black = 0,         Red = 1,         Green = 2,         Blue = 4     };     static void Main( )     {         Console.WriteLine(             "This example of the FlagsAttribute attribute \n" +             "generates the following output." );         Console.WriteLine(             "\nAll possible combinations of values of an \n" +             "Enum without FlagsAttribute:\n" );                 // Display all possible combinations of values.         for( int val = 0; val <= 8; val++ )             Console.WriteLine( "{0,3} - {1}",  val, ( (SingleHue)val ).ToString( ) );         Console.WriteLine(  "\nAll possible combinations of values of an \n" + "Enum with FlagsAttribute:\n" );                 // Display all possible combinations of values.         // Also display an invalid value.         for( int val = 0; val <= 8; val++ )             Console.WriteLine ( "{0,3} - {1}",  val, ( (MultiHue)val ).ToString( ) );     } } /* This example of the FlagsAttribute attribute generates the following output. All possible combinations of values of an Enum without FlagsAttribute:   0 - Black   1 - Red   2 - Green   3 - 3   4 - Blue   5 - 5   6 - 6   7 - 7   8 - 8 All possible combinations of values of an Enum with FlagsAttribute:   0 - Black   1 - Red   2 - Green   3 - Red, Green   4 - Blue   5 - Red, Blue   6 - Green, Blue   7 - Red, Green, Blue   8 - 8 */ 5、枚举作为函数参数。经常和switch结合起来使用。下面举例         public static double GetPrice(Fabric fab)         {             switch (fab)             {                 case Fabric.Cotton: return (3.55);                 case Fabric.Silk: return (5.65);                 case Fabric.Wool: return (4.05);                 case Fabric.Rayon: return (3.20);                 case Fabric.Other: return (2.50);                 default: return (0.0);             }         } 6、上面三点一个完整的例子         //1、enum的定义         public enum Fabric : short         {             Cotton = 1,             Silk = 2,             Wool = 3,             Rayon = 8,             Other = 128         }         //将枚举作为参数传递         public static double GetPrice(Fabric fab)         {             switch (fab)             {                 case Fabric.Cotton: return (3.55);                 case Fabric.Silk : return (5.65);                 case Fabric.Wool: return (4.05);                 case Fabric.Rayon: return (3.20);                 case Fabric.Other: return (2.50);                 default: return (0.0);             }         }         public static void Main()         {             Fabric fab = Fabric.Cotton;             int fabNum = (int)fab;             string fabType = fab.ToString();             string fabVal = fab.ToString ("D");             double cost = GetPrice(fab);             Console.WriteLine("fabNum = {0}\nfabType = {1}\nfabVal = {2}\n", fabNum, fabType, fabVal);             Console.WriteLine("cost = {0}", cost);         } 7、Enum类的使用 Enum.IsDefinde、Enum.Parse两种方法经常一起使用，来确定一个值或符号是否是一个枚举的成员，然后创建一个实例。Enum.GetName打印出一个成员的值；Enum.GetNames打印出所有成员的值。其中注意typeof的使用。这一点很重要。         public enum MyFamily         {             YANGZHIPING = 1,             GUANGUIQIN = 2,             YANGHAORAN = 4,             LIWEI = 8,             GUANGUIZHI = 16,             LISIWEN = 32,             LISIHUA = 64,         }             string s = "YANGHAORAN";             if (Enum.IsDefined(typeof(MyFamily), s))             {                 MyFamily f = (MyFamily)Enum.Parse(typeof(MyFamily), s);                 GetMyFamily(f);                 Console.WriteLine("The name is:" + Enum. GetName(typeof(MyFamily), 2));                 string[] sa = Enum.GetNames(typeof(MyFamily));                 foreach (string ss in sa)                 {                     Console.WriteLine(ss);