基础才是重中之重~LazyInitializer.EnsureInitialized对属性实现化的性能优化_.NET_编程开发_程序员俱乐部

LazyInitializer.EnsureInitialized是frameworks4.0引入的新东西，实现对属性延时初始化的功能，它作用在System.Threading命名空间下，所以，它与多线程有着密切的关系，即当多人同步使用这个方法时，对存储的对象有着某种作用，这是msdn的相关说明：

这个方法可以用于多个执行者初始化Target目录对象。

在多个执行者同时存取这个方法的情况下，可能会建立多个T执行个体，但只有一个执行个体会存储至target。在些类情况下，这个方法将不会放置未储存的对象。如果这类对象必须被放置，则由呼叫端判断未使的对象，然后再对物件进行适当的放置。

对于概念不清楚的同步，没有关系，看下面的例子如完全明白了，呵呵

下面的实例介绍了对属性的两个初始化，并进行比较，延时初始化的好处，即在对象使用时再去初始化它，当一个方法体中，如果一个对象初始化了一次，不要再进行重复的初始化工作。

代码1，展现了性能不好的情况

代码2，展现了优化的情况

代码3，微软为了我们进行了封装，在多线程中表现更好

代码1：

  class TestLazyInitializer1
    {

        public People People
        {
            get
            {

                return new People();

            }
        }

        public void Print1()
        {
            Console.WriteLine(People.Name);
        }
        public void Print2()
        {
            Console.WriteLine(People.Name);
        }

    }

代码2：

 class TestLazyInitializer2
    {
        People _people;
        public People People
        {
            get
            {

                return _people == null
                    ? (_people = new People())
                    : _people;

            }
        }

        public void Print1()
        {
            Console.WriteLine(People.Name);
        }
        public void Print2()
        {
            Console.WriteLine(People.Name);
        }

    }

代码3：

 class TestLazyInitializer
    {
        private People _people;
        /// <summary>
        /// 延时初始化指定属性
        /// </summary>
        public People People
        {
            get
            {
                return LazyInitializer.EnsureInitialized(
                    ref _people, () =>
                    {
                        return new People();
                    });
            }
        }

        public void Print1()
        {
            Console.WriteLine(People.Name);
        }
        public void Print2()
        {
            Console.WriteLine(People.Name);
        }

    }

而它们运行的结果，我们可想而知了，当一个类中多次使用同一个对象时，性能不好的，返回的Name(当前时间)，肯定是不同的，而性能好的，只初始化一次的，返回的Name(当前时间)肯定是一个值，呵呵。

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aMXClbe7fG6QqeGJmIfEF5pPuXcaiHPGfz957Cj1nr6iH9WhPXY/6rQGHgq5AAJAHSAiAJkBYASYC0AEgCfl+LH0/oswdX+6BgXH5Me9Bog+Tg97VcPom8OG45GTGz44wMpFV34Pe1rA5d8WhtzKus7Wk/1t6D/BDNQM3A72sxPXPGoUxpeQMGNQa/r8V0To+Dy4O136CQOI2DUgMlgd/XYrakxyHUW6iHYv2AMsDvazFbcsYhKDvOaDOjcucBagd+X4sZD2ccXA1Cs8jvB9Qe/L5WnJ9QV1a714M3/iA/oFTwaQwAkgBpAZAESAuAJEBaACQB0gIgCZAWAEmAtABIAqQFQBIgLQCSAGkBkARIC4AkQFoAJAHSAiAJkBYASYC0AEgCpAVAEiAtAFLwf9C8Ybsdp4uYAAAAAElFTkSuQmCC" 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感谢阅读！