c#単例モード

using System;

using System.Collections.Generic;

using System.Text;



namespace  

{

    class Program

    {

        static void Main(string[] args)

        {

            Singleton s1 = Singleton.GetInstance();

            Singleton s2 = Singleton.GetInstance();



            if (s1 == s2)

            {

                Console.WriteLine("Objects are the same instance");

            }



            Console.Read();

        }

    }





    class Singleton

    {

        private static Singleton instance;

        private static readonly object syncRoot = new object();

        private Singleton()

        {

        }



        public static Singleton GetInstance()

        {

            if (instance == null)

            {



                lock (syncRoot)// 

                {



                    if (instance == null)// ， ， ， 

                    {

                        instance = new Singleton();

                    }

                }

            }

            return instance;

        }



    }



    //public sealed class Singleton

    //{

    //    private static readonly Singleton instance = new Singleton();

    //    private Singleton() { }

    //    public static Singleton GetInstance()

    //    {

    //        return instance;

    //    }

    //}

}