ASP.NET Core Dependency Injection 3

Question 1

Which lifetime should be used for a service that maintains shared state across all requests?

Accepted Answer

Singleton

Answer

Scoped

Answer

Transient

Answer

PerThread

Question 2

What is the default DI container used in ASP.NET Core?

Accepted Answer

Microsoft.Extensions.DependencyInjection

Answer

Autofac

Answer

Ninject

Answer

Unity

Question 3

How is scope validation enabled in ASP.NET Core DI to detect captive dependencies?

Accepted Answer

Set ValidateScopes = true in ServiceProviderOptions

Answer

Call services.ValidateScopes()

Answer

Add UseValidation() to the pipeline

Answer

It is always enabled automatically

Question 4

Which method lets you replace an existing service registration in ASP.NET Core DI?

Accepted Answer

services.Replace(ServiceDescriptor.Scoped<IService, NewImpl>())

Answer

services.Override<IService, NewImpl>()

Answer

services.Swap<IService, NewImpl>()

Answer

services.Update<IService, NewImpl>()

Question 5

What happens if a service is not registered and GetService<T>() is called?

Accepted Answer

It returns null

Answer

It throws InvalidOperationException

Answer

It creates a default instance

Answer

It registers the service automatically

Question 6

Which interface allows a service to perform cleanup when the DI scope is disposed?

Accepted Answer

IDisposable

Answer

ICleanupService

Answer

IScopedCleanup

Answer

IAsyncDisposable only