inject-attribute.md

July 3, 2026 · View on GitHub

Inject attribute

If you want attributes without defining your own, add this package:

It provides Inject and Inject<T> for constructors, methods, properties, and fields, letting you configure injection metadata.

using Shouldly;
using Pure.DI.Abstractions;
using Pure.DI;

DI.Setup(nameof(PersonComposition))
    .Arg<int>("personId")
    .Bind<Uri>("Person Uri").To(() => new Uri("https://github.com/DevTeam/Pure.DI"))
    .Bind("NikName").To(() => "Nik")
    .Bind().To<Person>()

    // Composition root
    .Root<IPerson>("Person");

var composition = new PersonComposition(personId: 123);
var person = composition.Person;
person.ToString().ShouldBe("123 Nik https://github.com/DevTeam/Pure.DI");

interface IPerson;

class Person([Inject("NikName")] string name) : IPerson
{
    private object? _state;

    [Inject<int>] internal object Id = "";

    public void Initialize([Inject<Uri>("Person Uri", 1)] object state) =>
        _state = state;

    public override string ToString() => $"{Id} {name} {_state}";
}

Running this code sample locally

Make sure you have the .NET SDK 10.0 or later installed

dotnet --list-sdk

Create a net10.0 (or later) console application

dotnet new console -n Sample

Add references to the NuGet packages

dotnet add package Pure.DI
dotnet add package Shouldly
dotnet add package Pure.DI.Abstractions

Copy the example code into the Program.cs file

You are ready to run the example 🚀

dotnet run

This package should also be included in a project:

The following partial class will be generated

partial class PersonComposition
{
  private readonly int _argPersonId;

  [OrdinalAttribute(128)]
  public PersonComposition(int personId)
  {
    _argPersonId = personId;
  }

  public IPerson Person
  {
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    get
    {
      string transientString = "Nik";
      Uri transientUri = new Uri("https://github.com/DevTeam/Pure.DI");
      var transientPerson = new Person(transientString);
      transientPerson.Id = _argPersonId;
      transientPerson.Initialize(transientUri);
      return transientPerson;
    }
  }
}

Class diagram:

---
 config:
  class:
   hideEmptyMembersBox: true
---
classDiagram
	Person --|> IPerson
	PersonComposition ..> Person : IPerson Person
	Person o-- Int32 : Argument "personId"
	Person *-- Uri : "Person Uri" Uri
	Person *-- String : "NikName" String
	namespace Pure.DI.UsageTests.Attributes.InjectAttributeScenario {
		class IPerson {
			<<interface>>
		}
		class Person {
				<<class>>
			+Person(String name)
			~Object Id
			+Initialize(Object state) : Void
		}
		class PersonComposition {
		<<partial>>
		+IPerson Person
		}
	}
	namespace System {
		class Int32 {
				<<struct>>
		}
		class String {
				<<class>>
		}
		class Uri {
				<<class>>
		}
	}