(DesignPattern)Singleton.-创新互联

The purpose of the Singleton pattern is to ensure that there is only one instance of a class, and that there is a global access point to that object.

Design:

• Make the constructor private and add a private static constructor as well.
• Add a private static read-only object that is internally instantialed using the private constructor.
• Add a public static property that accesses the private object.

Implementation:

  public sealed class Singleton
    {
// Private constructor.   private Singleton()
        {
            Console.WriteLine("One instance is created."); 
        }

// private object instantiated with private constructor.   private static readonly Singleton instance = new Singleton(); 

// Public static property to get the object.   public static Singleton UniqueInstance
        {
get
            {
return instance; 
            }
        }
    }

  class Program
    {
static void Main(string[] args)
        {
            Singleton s0= Singleton.UniqueInstance;
            Singleton s1= Singleton.UniqueInstance;
            Singleton s2= Singleton.UniqueInstance; 
        }
    }