ASP.NET Core Dependency Injection 2

Question 1

Which method retrieves a required service and throws if it is not registered?

Accepted Answer

GetRequiredService<T>()

Answer

GetRequiredService() throws InvalidOperationException if the service is not found, unlike GetService() which returns null.

Question 2

How do you inject multiple implementations of the same interface in ASP.NET Core DI?

Accepted Answer

Inject IEnumerable<TService> in the constructor

Answer

ASP.NET Core DI resolves all registered implementations of an interface when IEnumerable<TService> is injected.

Question 3

What is the purpose of the IServiceScope interface in ASP.NET Core?

Accepted Answer

It creates a child DI scope for resolving scoped services outside a request

Answer

IServiceScope provides a scoped IServiceProvider, used to resolve scoped services in background services or tests.

Question 4

Which DI registration method allows providing a factory function instead of a type?

Accepted Answer

services.AddScoped<T>(sp => new T(...))

Answer

The overload accepting Func<IServiceProvider, T> allows custom construction logic using the service provider.

Question 5

What is constructor injection in ASP.NET Core DI?

Accepted Answer

Declaring dependencies as constructor parameters that the DI container resolves automatically

Answer

Constructor injection is the primary DI pattern where ASP.NET Core resolves and passes dependencies automatically when creating the class.

ASP.NET Core Practice Test