设计模式——单例模式

    internal class SingletonOne
    {
        private static SingletonOne _singleton;
        private SingletonOne()
        {
        }

        public static SingletonOne Instance
        {
            get
            {
                if (_singleton == null)
                {
                    Interlocked.CompareExchange(ref _singleton, new SingletonOne(), null);
                }

                return _singleton;
            }
        }
    }