1.       Singleton单件模式(创建型模式)

using System;

using System.Collections.Generic;

using System.Text;

namespace ConsoleApplication1

{

    ///<summary>

    ///单线程Singleton模式

    ///保证一个类仅有一个实例，并提供一个该实例的全局访问点。

    ///</summary>

    public class Singleton

    {

        private static Singleton instance;

        private Singleton(){}

        public static Singleton Instance

        {

            get

            {

                if (instance == null)

                {

                    instance = new Singleton();

                }

                return instance;

            }

        }

}

    class Test

    {

        public static void Main()

        {

            Singleton t1 = Singleton.Instance;

            Singleton t2 = Singleton.Instance;

            Console.WriteLine(object.ReferenceEquals(t1, t2) == true);

        }

 }

}