ContravariantRegistrationSource Class

Enables contravariant Resolve() for interfaces that have a single contravariant ('in') parameter.

Inheritance Hierarchy

SystemObject
Autofac.Features.VarianceContravariantRegistrationSource

Namespace: Autofac.Features.Variance
Assembly: Autofac (in Autofac.dll) Version: 6.0.0+39696a967e8826f7f1ebc8c1ff4523c9dd75abe0

Syntax

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public class ContravariantRegistrationSource : IRegistrationSource

Public Class ContravariantRegistrationSource
	Implements IRegistrationSource

The ContravariantRegistrationSource type exposes the following members.

Constructors

	Name	Description
	ContravariantRegistrationSource	Initializes a new instance of the ContravariantRegistrationSource class

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Properties

	Name	Description
	IsAdapterForIndividualComponents	Gets a value indicating whether the registrations provided by this source are 1:1 adapters on top of other components (e.g., Meta, Func, or Owned).

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Methods

	Name	Description
	Equals	Determines whether the specified object is equal to the current object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Serves as the default hash function. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	RegistrationsFor	Retrieve registrations for an unregistered service, to be used by the container.
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Examples

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interface IHandler<in TCommand>
{
    void Handle(TCommand command);
}

class Command { }

class DerivedCommand : Command { }

class CommandHandler : IHandler<Command> { ... }

var builder = new ContainerBuilder();
builder.RegisterSource(new ContravariantRegistrationSource());
builder.RegisterType<CommandHandler>();
var container = builder.Build();
// Source enables this line, even though IHandler<Command> is the
// actual registered type.
var handler = container.Resolve<IHandler<DerivedCommand>>();
handler.Handle(new DerivedCommand());

Reference

Autofac.Features.Variance Namespace