C# 单例的实现

1. 静态单例

using System;
using System.Collections.Generic;

namespace InstanceTest
{
    public class DogManager {
        public static readonly DogManager Instance = new DogManager();

        private DogManager() { }

        public void Eat() {
            Console.WriteLine("吃");
        }
    }
     
    class Program
    {
        static void Main(string[] args)
        {
            DogManager.Instance.Eat();
        }
    }
}

2.延时单例

using System;
using System.Collections.Generic;

namespace InstanceTest
{
    public class DogManager {
        private static DogManager _instance = null;

        private DogManager() { }

        public static DogManager Insance() {
            if (_instance == null) {
                _instance = new DogManager();
            }
            return _instance;
        }

        public void Eat() {
            Console.WriteLine("吃");
        }
    }
     
    class Program
    {
        static void Main(string[] args)
        {
            DogManager.Insance().Eat();
        }
    }
}

注意把构造函数写成private，让他不能通过new获得。