C#單例---餓漢式和懶漢式

單例模式:

步驟:

1.定義靜態私有對象

2.構造函數私有化

3.定義一個靜態的,返回值為該類型的方法,一般以Getinstance/getInit為方法名稱

單例模式有懶漢和餓漢,最好使用餓漢

1.餓漢式---先實例化

public class Singleton
    {
        private static Singleton  _singleton = new Singleton();//1
        private Singleton()  //2
        {
        }
        public static Singleton GetInstance()  //3
        {

            return _singleton;
        }


    }

2.懶漢式---後實例化

using System;

namespace 單例懶漢
{

 public class Singleton

    {
        private static Singleton _singleton;   //1
        private Singleton()   // 2
        {

        }
        public static Singleton GetInstance()  3
        {
            if (_singleton == null)
            {
                _singleton = new Singleton();
            }
            return _singleton;
        }
   }
}