Class DependencyInjectionTypeRegistrar

Namespace

Ploch.CommandLine.Spectre.DependencyInjection

Assembly

Ploch.CommandLine.Spectre.dll

Provides an implementation of Spectre.Console's Spectre.Console.Cli.ITypeRegistrar that integrates with Microsoft.Extensions.DependencyInjection for dependency injection.

public sealed class DependencyInjectionTypeRegistrar : ITypeRegistrar

Inheritance

object

DependencyInjectionTypeRegistrar

Implements

ITypeRegistrar

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

Lifetimes follow one rule. Everything registered through Register(Type, Type) — which is how Spectre registers every command, settings type, type converter and pair deconstructor — is transient: a new instance is created for every resolution, so a command holds its transient dependencies for its own lifetime rather than the host's. Dependency lifetimes are unchanged, so singleton services stay shared. RegisterInstance(Type, object) and RegisterLazy(Type, Func<object>?) are singletons, because that is what Spectre's contract asks for: the first must hand back the very instance it was given, and the second describes a lazily created instance: the first instance the factory creates successfully is shared by every later resolution, while a factory that throws is run again on the next resolution, because the container caches only a created instance.

The infrastructure the library registers itself — the console, the IOutput, the message formatter processor and the application's CancellationTokenSource — stays singleton by design: those are shared or stateless, and a command is meant to receive the same instance the application uses.

Spectre registers its types when the application runs, after every ConfigureServices delegate, and the last registration of a service type wins. Registering a command type as a singleton from ConfigureServices therefore has no effect; state that must outlive one resolution belongs in a singleton service the command depends on.

Constructors

DependencyInjectionTypeRegistrar(IHostBuilder)

Provides an implementation of Spectre.Console's Spectre.Console.Cli.ITypeRegistrar that integrates with Microsoft.Extensions.DependencyInjection for dependency injection.

Methods

Build()

Builds and returns a type resolver that can resolve types from the configured service provider.

Register(Type, Type)

Registers a service type with its corresponding implementation type as a transient service, so every resolution creates a new instance.

RegisterInstance(Type, object)

Registers an existing instance as a singleton service, so every resolution returns that very instance, as Spectre's contract requires.

RegisterLazy(Type, Func<object>?)

Registers a factory function that will be invoked to create an instance of the service when needed. The result is a lazily created singleton: the factory runs on the first resolution and every later resolution returns the same instance.