FactoryTypeRegistration

Table Of Contents

• Factory Type Registration
  • Implementing IFactory<T> and IAsyncFactory<T>
  • Disposal
  • Example

Factory Type Registration

If a type implements IFactory<T> or IAsyncFactory<T> you can register it as a provider for T using the [RegisterFactory] attribute. StrongInject will look for a suitable constructor to instantiate the type, as described here.

RegisterFactoryAttribute has 3 parameters.

[AttributeUsage(AttributeTargets.Class, AllowMultiple = true, Inherited = false)]
public class RegisterFactoryAttribute : Attribute
{
    public RegisterFactoryAttribute(Type factoryType, Scope factoryScope = Scope.InstancePerResolution, Scope factoryTargetScope = Scope.InstancePerResolution);

    public Type FactoryType { get; }
    public Scope FactoryScope { get; }
    public Scope FactoryTargetScope { get; }
}

factoryType will be registered as a factory for any type T such that it implements IFactory<T> or IAsyncFactory<T>. A warning will be issued if it does not implement either interface.

factoryScope is used to control how often the factory is instantiated.

factoryTargetScope is used to control how often an instance of T will be created from the factory.

Implementing IFactory<T> and IAsyncFactory<T>

See the documentation (WIP).

Disposal

If factoryType implements IDisposable or IAsyncDisposable, an instance of factoryType will be automatically disposed by StrongInject once it is no longer used.

Any instances created by the factory will be passed to IFactory<T>.Release(T)/IAsyncFactory<T>.ReleaseAsync(T) once they are no longer used. It is the factory's responsibility to dispose them. See the documentation (WIP).

Example

using StrongInject;
using System;

public class A : IDisposable { public void Dispose() { } }
public class Factory : IFactory<A>, IDisposable
{
    public A Create() => new A();

    public void Dispose() { }

    public void Release(A instance) => instance.Dispose();
}

[RegisterFactory(typeof(Factory), Scope.SingleInstance, Scope.InstancePerResolution)]
public partial class Container : IContainer<A> { }

var container = new Container();
container.Run(x => Console.WriteLine(x.ToString())); // Will create a new instance of Factory. Will call Factory.Create() to create an instance of A. After the lambda completes, will call factory.Release() to dispose of the instance of A.
container.Run(x => Console.WriteLine(x.ToString())); // Will reuse the existing instance of Factory since it is SingleInstance. Will call Factory.Create() to create an instance of A since it is InstancePerResolution. After the lambda completes, will call factory.Release() to dispose of the instance of A.
container.Dispose(); // Will dispose of the single instance of Factory