ASP.NET Core IOC容器

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            //IOC容器支持依赖注入
            {
                ServiceCollection serviceDescriptors = new ServiceCollection();
                serviceDescriptors.AddTransient<IMicrophone, Microphone>();
                serviceDescriptors.AddTransient<IPower, Power>();
                serviceDescriptors.AddTransient<IHeadphone, Headphone>();
                ServiceProvider serviceProvider =serviceDescriptors.BuildServiceProvider();
                IHeadphone headphone = serviceProvider.GetService<IHeadphone>();
            }

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AddTransient：瞬时生命周期,每一次创建都是是一个全新的实例
ServiceCollection serviceDescriptors = new ServiceCollection();
serviceDescriptors.AddTransient<IMicrophone, Microphone>();
ServiceProvider serviceProvider =serviceDescriptors.BuildServiceProvider();
IMicrophone microphone1 = serviceProvider.GetService<IMicrophone>();

AddSingleton：单例生命周期：同一个类型，创建出来的是同一个实例
ServiceCollection serviceDescriptors = new ServiceCollection();
serviceDescriptors.AddSingleton<IMicrophone, Microphone>();
ServiceProvider serviceProvider = serviceDescriptors.BuildServiceProvider();
IMicrophone microphone1 = serviceProvider.GetService<IMicrophone>();

AddScoped：作用域生命周期： 同一个serviceProvider获取到的是同一个实例
ServiceCollection serviceDescriptors = new ServiceCollection();
serviceDescriptors.AddScoped<IMicrophone, Microphone>();
ServiceProvider serviceProvider1 = serviceDescriptors.BuildServiceProvider();
IMicrophone microphone1 = serviceProvider1.GetService<IMicrophone>();

ServiceCollection 抽象和具体之间多种注册方式

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{
    ServiceCollection serviceDescriptors = new ServiceCollection();
    serviceDescriptors.AddTransient<IMicrophone, Microphone>();
    ServiceProvider serviceProvider1 = serviceDescriptors.BuildServiceProvider();
    IMicrophone microphone1 = serviceProvider1.GetService<IMicrophone>();
}
{
    ServiceCollection serviceDescriptors = new ServiceCollection();
    serviceDescriptors.AddTransient(typeof(IMicrophone), typeof(Microphone));
    ServiceProvider serviceProvider1 = serviceDescriptors.BuildServiceProvider();
    IMicrophone microphone1 = serviceProvider1.GetService<IMicrophone>();
}
//注册抽象和一段业务逻辑
{
    ServiceCollection serviceDescriptors = new ServiceCollection();
    serviceDescriptors.AddTransient(typeof(IPower), provider =>
    {
        //在这里可以我们自己来决定如何创建这个对象的实例；可以对创建出来的这个实例，可以做加工
        IMicrophone microphone = provider.GetService<IMicrophone>();
        return new Power(microphone);
    });

    serviceDescriptors.AddTransient(typeof(IMicrophone), typeof(Microphone));
    ServiceProvider serviceProvider1 = serviceDescriptors.BuildServiceProvider();
    IPower power = serviceProvider1.GetService<IPower>();
}
{
    ServiceCollection serviceDescriptors = new ServiceCollection();
    serviceDescriptors.AddTransient(typeof(Microphone));
    ServiceProvider serviceProvider1 = serviceDescriptors.BuildServiceProvider();
    Microphone microphone1 = serviceProvider1.GetService<Microphone>();
}

{
    ServiceCollection serviceDescriptors = new ServiceCollection();
    serviceDescriptors.AddTransient<Microphone>();
    ServiceProvider serviceProvider1 = serviceDescriptors.BuildServiceProvider();
    Microphone microphone1 = serviceProvider1.GetService<Microphone>();
}