singleton pattern简单随笔

单件模式，就是确保一个类只有一个实例，并提供一个全局访问点。

 1 namespace SingletonPatternSam
 2 {
 3     class Program
 4     {
 5         static void Main(string[] args)
 6         {
 7             SamSingleton.Instance.Display();
 8             Console.WriteLine(SamSingleton.Instance.ToString());
 9             Console.ReadLine();
10         }
11     }
12 
13     public sealed class SamSingleton
14     {
15         private static string str = "";
16         private static readonly SamSingleton instance = new SamSingleton();//构造实例对象
17         static SamSingleton()
18         {
19             str = "KKK";
20         }
21         public static SamSingleton Instance
22         {
23             get { return instance; }
24         }
25         
26         public void Display()
27         {
28             Console.WriteLine("XXXX");
29         }
30         public override string ToString()
31         {
32             return str;
33         }
34     }
35 }