C# 单例

using System;
using System.Threading;

namespace Singleton
{
    class Program
    {
        static void Main(string[] args)
        {
            Singleton s1 = Singleton.CreateInstance();
            Singleton s2 = Singleton.CreateInstance();
            Console.WriteLine(s1 == s2);
            Console.ReadKey();
        }
    }

    class Singleton
    {
        private static Singleton instance;
        private Singleton() { }//私有构造函数，防止实例化
        private static object obj = new object();//通过Lock关键字实现同步
        public static Singleton CreateInstance()
        {
            if (instance == null)
            {
                lock (obj)
                {
                    if (instance == null)
                    {
                        instance = new Singleton();
                    }

                }
            }
            return instance;
        }

    }
}