C# 单例模式

饿汉， 懒汉模式就不说了，下面是IODH模式

  static void Main(string[] args)
        {
            Singleton s1, s2;
            s1 = Singleton.getInstance();
            s2 = Singleton.getInstance();
            var obj = System.Object.Equals(s1, s2);
        }

  public class Singleton
     {
         private Singleton() { }
         private static class HolderClass
         {
             public static Singleton instance = new Singleton();
         }
         public static Singleton getInstance()
         {
             return HolderClass.instance;
         }
     }