C# 两行代码实现 延迟加载的单例模式（线程安全）
关键代码第4，5行。
很简单的原理不解释：readonly + Lazy(.Net 4.0 + 的新特性)
1 public class LazySingleton 2 { 3 //Lazy singleton 4 private LazySingleton() { Console.WriteLine("Constructing"); } 5 private static readonly Lazy<LazySingleton> Linstance = new Lazy<LazySingleton>(() => { return new LazySingleton(); }); 6 7 //not lazy Singleton 8 //public static readonly LazySingleton instance = new LazySingleton(); 9 10 public String Name { get; set; } 11 public static LazySingleton Instance { get { return Linstance.Value; } } 12 13 //For test 14 public static bool IsValueCreated { get { return Linstance.IsValueCreated; } } 15 } 16 17 public class LazySingletonDemo 18 { 19 public static void Execute() 20 { 21 Task.Run(() => Foo1()); 22 //Thread.Sleep(1000); 23 Task.Run(() => Foo1()); 24 Task.Run(() => Foo1()); 25 26 } 27 28 public static void Foo1() 29 { 30 if (!LazySingleton.IsValueCreated) 31 Console.WriteLine("LazySingleton is not initialized"); 32 33 LazySingleton.Instance.Name = "HK"; 34 35 Console.WriteLine(LazySingleton.Instance.Name); 36 } 37 }
测试结果：
