获取Enum中项个数的优雅方法

在Microsoft.Practices.ObjectBuilder2中的StagedStrategyChain<TStageEnum>类中只用的下面的方法来获取枚举里元素的个数：

   1: private static int NumberOfEnumValues()

   2: {

   3:       return typeof(TStageEnum).GetFields(BindingFlags.Public | BindingFlags.Static).Length;

   4: }

使用方式：

   1: readonly List<IBuilderStrategy>[] stages;

   2:  

   3: /// <summary>

   4: /// Initialize a new instance of the <see cref="StagedStrategyChain{TStageEnum}"/> class.

   5: /// </summary>

   6: public StagedStrategyChain()

   7: {

   8:      stages = new List<IBuilderStrategy>[NumberOfEnumValues()];

   9:  

  10:        for(int i = 0; i < stages.Length; ++i)

  11:        {

  12:            stages[i] = new List<IBuilderStrategy>();

  13:        }

  14: }