TL; DR
瞬态对象总是不同的。为每个控制器和每个服务提供一个新实例。
范围对象在一个请求中是相同的，但在不同的请求中是不同的。
每个对象和每个请求的单例对象都是相同的。
为了进一步说明，来自ASP.NET文档的此示例显示了以下区别：
为了说明这些生存期和注册选项之间的区别，请考虑一个简单的界面，该界面将一个或多个任务表示为具有唯一标识符的操作OperationId。根据我们如何配置此服务的生存期，容器将为请求的类提供相同或不同的服务实例。为了清楚说明请求哪个生存期，我们将为每个生存期创建一个类型的选项：
using System;
namespace DependencyInjectionSample.Interfaces
{
public interface IOperation
{
Guid OperationId { get; }
}
public interface IOperationTransient : IOperation
{
}
public interface IOperationScoped : IOperation
{
}
public interface IOperationSingleton : IOperation
{
}
public interface IOperationSingletonInstance : IOperation
{
}
}
我们使用单个类（）来实现这些接口，该类Operation在其构造函数中接受GUID；如果未提供，则使用新的GUID：
using System;
using DependencyInjectionSample.Interfaces;
namespace DependencyInjectionSample.Classes
{
public class Operation : IOperationTransient, IOperationScoped, IOperationSingleton, IOperationSingletonInstance
{
Guid _guid;
public Operation() : this(Guid.NewGuid())
{
}
public Operation(Guid guid)
{
_guid = guid;
}
public Guid OperationId => _guid;
}
}
接下来，在中ConfigureServices，根据其命名生命周期将每种类型添加到容器中：
services.AddTransient<IOperationTransient, Operation>();
services.AddScoped<IOperationScoped, Operation>();
services.AddSingleton<IOperationSingleton, Operation>();
services.AddSingleton<IOperationSingletonInstance>(new Operation(Guid.Empty));
services.AddTransient<OperationService, OperationService>();
请注意，该IOperationSingletonInstance服务正在使用ID为的特定实例Guid.Empty，因此使用此类型时将很清楚。我们还注册了一个OperationService依赖于其他每种Operation类型的，因此对于每种操作类型，该请求将清楚地表明此服务是与控制器使用相同的实例，还是获得新的实例。该服务所做的全部工作就是将其依赖项公开为属性，以便可以在视图中显示它们。
using DependencyInjectionSample.Interfaces;
namespace DependencyInjectionSample.Services
{
public class OperationService
{
public IOperationTransient TransientOperation { get; }
public IOperationScoped ScopedOperation { get; }
public IOperationSingleton SingletonOperation { get; }
public IOperationSingletonInstance SingletonInstanceOperation { get; }
public OperationService(IOperationTransient transientOperation,
IOperationScoped scopedOperation,
IOperationSingleton singletonOperation,
IOperationSingletonInstance instanceOperation)
{
TransientOperation = transientOperation;
ScopedOperation = scopedOperation;
SingletonOperation = singletonOperation;
SingletonInstanceOperation = instanceOperation;
}
}
}
为了演示对应用程序的各个单独请求之内和之间的对象生存期，该示例包括一个OperationsController请求每种类型的请求IOperation以及一个请求OperationService。Index然后，该操作将显示所有控制器和服务的OperationId值。
using DependencyInjectionSample.Interfaces;
using DependencyInjectionSample.Services;
using Microsoft.AspNetCore.Mvc;
namespace DependencyInjectionSample.Controllers
{
public class OperationsController : Controller
{
private readonly OperationService _operationService;
private readonly IOperationTransient _transientOperation;
private readonly IOperationScoped _scopedOperation;
private readonly IOperationSingleton _singletonOperation;
private readonly IOperationSingletonInstance _singletonInstanceOperation;
public OperationsController(OperationService operationService,
IOperationTransient transientOperation,
IOperationScoped scopedOperation,
IOperationSingleton singletonOperation,
IOperationSingletonInstance singletonInstanceOperation)
{
_operationService = operationService;
_transientOperation = transientOperation;
_scopedOperation = scopedOperation;
_singletonOperation = singletonOperation;
_singletonInstanceOperation = singletonInstanceOperation;
}
public IActionResult Index()
{
// ViewBag contains controller-requested services
ViewBag.Transient = _transientOperation;
ViewBag.Scoped = _scopedOperation;
ViewBag.Singleton = _singletonOperation;
ViewBag.SingletonInstance = _singletonInstanceOperation;
// Operation service has its own requested services
ViewBag.Service = _operationService;
return View();
}
}
}
现在，对此控制器操作提出了两个单独的请求：
观察哪个OperationId值在请求内以及请求之间变化。
瞬态对象总是不同的。为每个控制器和每个服务提供一个新实例。
范围对象在一个请求中是相同的，但在不同的请求中是不同的
每个对象和每个请求的单例对象都相同（无论是否在中提供了实例ConfigureServices）
