generic-root-arguments.md

Generic root arguments

using Pure.DI;

DI.Setup(nameof(Composition))
    .RootArg<TT>("someArg")
    .Bind<IService<TT>>().To<Service<TT>>()

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

var composition = new Composition();
IService<int> service = composition.GetMyService<int>(someArg: 33);

interface IService<out T>
{
    T? Dependency { get; }
}

class Service<T> : IService<T>
{
    // The Dependency attribute specifies to perform an injection,
    // the integer value in the argument specifies
    // the ordinal of injection
    [Dependency]
    public void SetDependency(T dependency) =>
        Dependency = dependency;

    public T? Dependency { get; private set; }
}

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(128)]
  public Composition()
  {
    _root = this;
  }

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

  [MethodImpl(MethodImplOptions.AggressiveInlining)]
  public IService<T1> GetMyService<T1>(T1 someArg)
  {
    if (someArg is null) throw new ArgumentNullException(nameof(someArg));
    Service<T1> transientService0 = new Service<T1>();
    transientService0.SetDependency(someArg);
    return transientService0;
  }
}

Class diagram:

---
 config:
  class:
   hideEmptyMembersBox: true
---
classDiagram
	ServiceᐸT1ᐳ --|> IServiceᐸT1ᐳ
	Composition ..> ServiceᐸT1ᐳ : IServiceᐸT1ᐳ GetMyServiceᐸT1ᐳ(T1 someArg)
	ServiceᐸT1ᐳ o-- T1 : Argument "someArg"
	namespace Pure.DI.UsageTests.Generics.GenericRootArgScenario {
		class Composition {
		<<partial>>
		+IServiceᐸT1ᐳ GetMyServiceᐸT1ᐳ(T1 someArg)
		}
		class IServiceᐸT1ᐳ {
			<<interface>>
		}
		class ServiceᐸT1ᐳ {
			+Service()
			+SetDependency(T1 dependency) : Void
		}
	}

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