//MVC自带的三种依赖注入方式
//MVC自带的三种依赖注入方式public WeatherForecastController(ILogger<WeatherForecastController> logger, IConfiguration configuration, IHostEnvironment hostEnvironment){_logger = logger;this.configuration = configuration;this.hostEnvironment = hostEnvironment;}[HttpGet]public IEnumerable<WeatherForecast> Get(){var rng = new Random();//第二种依赖注入方式IHostEnvironment host = HttpContext.RequestServices.GetService(typeof(IHostEnvironment)) as IHostEnvironment;//第三种依赖注入方式var host2 = HttpContext.RequestServices.GetRequiredService<IHostEnvironment>();return Enumerable.Range(1, 5).Select(index => new WeatherForecast{Date = DateTime.Now.AddDays(index),TemperatureC = rng.Next(-20, 55),Summary = Summaries[rng.Next(Summaries.Length)]}).ToArray();}
public void ConfigureServices(IServiceCollection services){services.AddControllers();services.AddSingleton<IServiceCollection>();//每次都是原来的那个services.AddScoped<ILogger>(); //本次进入Controller的URL 获取的都是一样的services.AddTransient<ILogger>(); //每次都是新的services.AddSingleton<IServiceCollection>(x => new ServiceCollection());//等同于services.AddSingleton<IServiceCollection, ServiceCollection>();}
