Singleton mode in C #

Generally, Singleton is just like this.

class Singleton {public static Singleton  instance;private Singleton(){}public static Singleton Getinstance(){if(instatnce == null){instance = new Singleton();}return instance;}}

But today I learned a C # unique Singleton statement:

class sealed Singleton {public static readonly Singleton  instance = new Singleton();private Singleton(){}}

This method is simple and practical, greatly reducing the amount of code.

However, the disadvantage is that it cannot be inherited and initialized at startup, and initialization cannot be delayed.

 

In this way, I wrote a simple loadbalance class.

public sealed class LoadBalancer{    public static readonly LoadBalancer balancer = new LoadBalancer();    private ArrayList servers = new ArrayList();    private Random random = new Random();    protected LoadBalancer()     {        servers.Add("SERVER I");        servers.Add("SERVER II");        servers.Add("SERVER III");        servers.Add("SERVER IV");        servers.Add("SERVER V");    }    public string Server     {        get         {            int i = random.Next(servers.Count);            return servers[i].ToString();        }    }}class Program{    static void Main(string[] args)    {        LoadBalancer b1 = LoadBalancer.balancer;        LoadBalancer b2 = LoadBalancer.balancer;        LoadBalancer b3 = LoadBalancer.balancer;        LoadBalancer b4 = LoadBalancer.balancer;        if (b1 == b2 || b2 == b3 || b3 == b4)            Console.WriteLine("Same instance");        Console.WriteLine(b1.Server);        Console.WriteLine(b2.Server);        Console.WriteLine(b3.Server);        Console.WriteLine(b4.Server);        Console.ReadLine();    }}

The call result is:

 

Same instance

Server III

Server I

Server IV

Server IV