DotNETCore 学习笔记 依赖注入和多环境

Dependency Injection
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ASP.NET services can be configured with the following lifetimes:

Transient
Transient lifetime services are created each time they are requested. This lifetime works best for 

lightweight, stateless services.

Scoped
Scoped lifetime services are created once per request.

Singleton
Singleton lifetime services are created the first time they are requested (or when ConfigureServices is run 

if you specify an instance there) and then every subsequent request will use the same instance. If your 

application requires singleton behavior, allowing the services container to manage the service’s lifetime 

is recommended instead of implementing the singleton design pattern and managing your object’s lifetime in 

the class yourself.

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"dependencies" : {
  "Autofac": "4.0.0",
  "Autofac.Extensions.DependencyInjection": "4.0.0"
},

public IServiceProvider ConfigureServices(IServiceCollection services)
{
  services.AddMvc();
  // add other framework services

  // Add Autofac
  var containerBuilder = new ContainerBuilder();
  containerBuilder.RegisterModule<DefaultModule>();
  containerBuilder.Populate(services);
  var container = containerBuilder.Build();
  return new AutofacServiceProvider(container);
}

public class DefaultModule : Module
{
  protected override void Load(ContainerBuilder builder)
  {
    builder.RegisterType<CharacterRepository>().As<ICharacterRepository>();
  }
}

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Working with Multiple Environments

ASPNETCORE_ENVIRONMENT：Development, Staging, and Production

env.IsEnvironment("environmentname")
or
env.EnvironmentName == "Development" 

Startup{EnvironmentName} (for example StartupDevelopment)

Configure{EnvironmentName}() ConfigureDevelopment() 

Configure{EnvironmentName}Services(). ConfigureDevelopmentServices（）