weak-reference.md

Weak Reference

using Pure.DI;

DI.Setup(nameof(Composition))
    .Bind<IDependency>().To<Dependency>()
    .Bind<IService>().To<Service>()

    // Composition root
    .Root<IService>("Root");

var composition = new Composition();
var service = composition.Root;

interface IDependency;

class Dependency : IDependency;

interface IService;

class Service(WeakReference<IDependency> dependency) : IService
{
    public IDependency? Dependency =>
        dependency.TryGetTarget(out var value)
            ? value
            : null;
}

Running this code sample locally

• Make sure you have the .NET SDK 9.0 or later is installed

dotnet --list-sdk

• Create a net9.0 (or later) console application

dotnet new console -n Sample

• Add reference to NuGet package
  • Pure.DI

dotnet add package Pure.DI

• Copy the example code into the Program.cs file

You are ready to run the example 🚀

dotnet run

The following partial class will be generated:

partial class Composition
{
  private readonly Composition _root;

  [OrdinalAttribute(256)]
  public Composition()
  {
    _root = this;
  }

  internal Composition(Composition parentScope)
  {
    _root = (parentScope ?? throw new ArgumentNullException(nameof(parentScope)))._root;
  }

  public IService Root
  {
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    get
    {
      return new Service(new WeakReference<IDependency>(new Dependency()));
    }
  }
}

Class diagram:

Loading

---
 config:
  class:
   hideEmptyMembersBox: true
---
classDiagram
	Dependency --|> IDependency
	Service --|> IService
	Composition ..> Service : IService Root
	Service *--  WeakReferenceᐸIDependencyᐳ : WeakReferenceᐸIDependencyᐳ
	WeakReferenceᐸIDependencyᐳ *--  Dependency : IDependency
	namespace Pure.DI.UsageTests.BCL.WeakReferenceScenario {
		class Composition {
		<<partial>>
		+IService Root
		}
		class Dependency {
			+Dependency()
		}
		class IDependency {
			<<interface>>
		}
		class IService {
			<<interface>>
		}
		class Service {
			+Service(WeakReferenceᐸIDependencyᐳ dependency)
		}
	}
	namespace System {
		class WeakReferenceᐸIDependencyᐳ {
			+WeakReference(IDependency target)
		}
	}