compile time dependency injection for .Net

• Aims
• Requirements
• Nuget
• Usage
  • Declaring a container
  • Using a container.
  • Registration
    • Basics
    • Scope
    • Modules
    • Instance fields and properties
    • Factories
    • Generic Factory Methods
    • Decorators
    • Providing registrations at runtime or integrating with other IOC containers
    • How StrongInject picks which registration to use
  • Delegate Support
  • Post Constructor Initialization
  • Async Support
  • Resolving all instances of a type
  • Disposal
  • Thread Safety
  • Inbuilt Modules
• Product Roadmap
• Contributing
• Need Help?

1. Compile time checked dependency injection. If the type you're resolving isn't registered you get an error at compile time, not runtime.
2. Fast. There's no dictionary lookups, no runtime code generation. Just the fastest code it's possible to generate to resolve your type.
3. Encourage best practices. You can't use the container as a service locator. You can't forget to dispose the resolved types.
4. No reflection or runtime code generation. Instead StrongInject uses roslyn Source Generators, meaning it's fast, and works well on UWP/IOS too. This also means it's linker friendly - see https://devblogs.microsoft.com/dotnet/app-trimming-in-net-5/.
5. Async support. StrongInject fully supports async initialization and disposal, a feature sorely lacking in many IOC containers.

Source generators are currently in preview and so you will require a preview version of VS and dotnet.

Visual Studio preview version >= 16.8 preview 4

.NET 5 preview version >= 5.0.100-rc.2

https://www.nuget.org/packages/StrongInject/

We recommend you use floating versions for now, as StrongInject is still in preview and changing rapidly. <PackageReference Include="StrongInject" Version="0.0.1-CI-*" />

The wiki is currently a work in progress. It aims to give a more thorough formal overview of everything in StrongInject, whereas this section of the readme gives a briefer overview relying heavily on examples. I would read through this first, then check out the wiki if you have any questions.

To create a container for a specific type, declare your container partial and inherit from StrongInject.IContainer<T>:

using StrongInject;

public class A {}

[Register(typeof(A))]
public partial class Container : IContainer<A> {}

If it's possible to resolve the type parameter StrongInject will generate the implementation of IContainer for you. Else it will produce an error diagnostic.

You can implement IContainer<T> for different values of T. They will all share SingleInstance dependencies.

using StrongInject;

public class A {}
public class B {}

[Register(typeof(A))]
[Register(typeof(B))]
public partial class Container : IContainer<A>, IContainer<B> {}

There are two ways to use a container - using the Run methods or the Resolve methods.

Either way you'll find it easier if you the extension methods defined in StrongInject.ContainerExtensions rather than those defined directly on the container, so make sure you're using StrongInject;

The Run method on IContainer<T> takes a Func<T, TResult>. It resolves an instance of T, calls the func, disposes of any dependencies which require disposal, and then returns the result of the func. This ensures that you can't forget to dispose any dependencies, but you must make sure not too leak those objects out of the delegate. There are also overloads that allow you to pass in a void returning lambda.

using StrongInject;

public class Program
{
  public static void Main()
  {
    System.Console.WriteLine(new Container().Run(x => x.ToString()));
  }
}

In some cases this isn't flexible enough, for example if you want to use StrongInject from another IOC container, or you need more fine grained control over the lifetime of T.

For these cases you can call the Resolve method. This reurns an Owned<T> which is essentially a disposable wrapper over T. Make sure you call Owned<T>.Dispose once you're done using Owned<T>.Value.

using StrongInject;

public class Program
{
  public static void Main()
  {
    using var ownedOfA = new Container().Resolve();
    var a = ownedOfA.Value;
    System.Console.WriteLine(a.ToString());
  }
}

As you saw above, you can register a type with a container using the RegistrationAttribute:

using StrongInject;

public class A {}
public class B {}

[Register(typeof(A))]
[Register(typeof(B))]
public partial class Container : IContainer<A>, IContainer<B> {}

All the dependencies of the container type parameter must be registered or you will get a compile time error.

By default [Register(typeof(A))] will register an type A as itself. You can however register a type as any base type or implemented interface:

using StrongInject;

public class BaseBase {}
public interface IBase {}
public class Base : BaseBase, IBase {}
public interface IA {}
public class A : Base, IA {}

[Register(typeof(A), typeof(IA), typeof(IBase), typeof(BaseBase))]
public partial class Container : IContainer<BaseBase> {}

If you do so, you will have to explicitly also register it as itself if that is desired: [Register(typeof(A), typeof(A), typeof(IA), typeof(IBase), typeof(BaseBase))]

If there is a single public non-parameterless constructor, StrongInject will use that to construct the type. If there is no public non-parameterless constructor StrongInject will use the parameterless constructor if it exists and is public. Else it will report an error.

The scope of a registration determines how often a new instance is created, how long it lives, and who uses it.

It can be set as the second parameter of a registration:

using StrongInject;

public class A {}
public interface IB {}
public class B : IB {}

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

There are currently 3 diferent scopes:

Instance Per Resolution

This is the default scope.

A single instance is shared between all dependencies created for a single resolution. For example if 'A' debends on 'B' and 'C', and 'B' and 'C' both depend on an instance of 'D', then when 'A' is resolved 'B' and 'C' will share the same instance of 'D'.

Note every SingleInstance dependency defines a seperate resolution, so if 'B' and/or 'C' are SingleInstance they would not share an instance of 'D'.

Instance Per Dependency

A new instance is created for every usage. For example even if type 'B' appears twice in the constructor of 'A', two different instances will be passed into the constructor.

SingleInstance

A single instance will be shared across all dependencies, from any resolution

You can add registrations to any type, and then import them using the ModuleRegistrationAttribute. This allows you to create reusable modules of common registrations.

using StrongInject;

public class A {}

[Register(typeof(A))]
public class Module {}

[RegisterModule(typeof(Module))]
public partial class Container : IContainer<A> {}

If you import multiple modules, and they both register the same type differently, you will get an error.

There are two ways to solve this:

1. Register the type directly. This will override the registrations in imported modules.
2. Exclude the registration from one of the modules when you import it: [RegisterModule(typeof(Module), exclusionList: new [] { typeof(A) })]

You can mark a field or a property with the [Instance] attribute, to register it as an instance of the field/property type. The field/property will be called for every dependency, but it is bad practice for it to be mutable or expensive, and so this should be irrelevant in practice.

using StrongInject;
using System.Collections.Generic;

public class A
{
    public A(Dictionary<string, object> configuration){}
}

[Register(typeof(A))]
public partial class Container : IContainer<A>
{
    [Instance] Dictionary<string, object> _configuration;
    public Container(Dictionary<string, object> configuration) => _configuration = configuration;
}

If the instance field/property is defined on the container type, it can be private or public, instance or static. However if you want to export the instance as part of a module it must be public and static.

using StrongInject;
using System;

public class A
{
    public A(IEqualityComparer<string> equalityComparer){}
}

public class StringEqualityComparerModule
{
    [Instance] public static IEqualityComparer<string> StringEqualityComparer = StringComparer.CurrentCultureIgnoreCase;
}

[Register(typeof(A))]
[RegisterModule(typeof(StringEqualityComparerModule))]
public partial class Container : IContainer<A>
{
}

If you want the instance to also be registered as its interfaces or base classes, or to be used as a factory for other types, you can configure all this and more using the options parameter. The above example could also have been registered like this:

using StrongInject;
using System;

public class A
{
    public A(IEqualityComparer<string> equalityComparer){}
}

public class StringEqualityComparerModule
{
    [Instance(Options.AsImplementedInterfaces)] public static StringComparer StringEqualityComparer = StringComparer.CurrentCultureIgnoreCase;
}

[Register(typeof(A))]
[RegisterModule(typeof(StringEqualityComparerModule))]
public partial class Container : IContainer<A>
{
}

Sometimes a type requires more complex construction than just calling the constructor. For example you might want to hard code some parameters, or call a factory method. Some types don't have the correct constructors to be registered directly.

In such cases you can write a method returning the type you want to construct and mark it with the [Factory] attribute.

using StrongInject;

public interface IInterface {}
public class A : IInterface {}
public class B : IInterface {}

[Register(typeof(A))]
[Register(typeof(B))]
public partial class Container : IContainer<IInterface[]>
{
    [Factory] private IInterface[] CreateInterfaceArray(A a, B b) => new IInterface[] { a, b };
}

You can set the scope of the factory method (how often it's called), by passing in the scope parameter: [Factory(Scope.SingleInstance)].

If the factory method is defined on the container type, it can be private or public, instance or static. However if you want to export the factory method as part of a module it must be public and static.

using StrongInject;

public interface IInterface {}
public class A : IInterface {}
public class B : IInterface {}

public class Module
{
    [Factory] public static IInterface[] CreateInterfaceArray(A a, B b) => new IInterface[] { a, b };
}

[Register(typeof(A))]
[Register(typeof(B))]
[RegisterModule(typeof(Module))]
public partial class Container : IContainer<IInterface[]>
{
}

If the factory method returns Task<T> or ValueTask<T> it will be considered an async registration for T (see below).

In some cases you want to maintain some state in your factory, or control disposal. For such cases the IFactory<T> interface exists.

You can register a type implementing IFactory<T> as a Factory Registration. This will automatically register it as both IFactory<T> and T. An instance of T will be constructed by calling IFactory<T>.Create().

using StrongInject;
using System.Buffers;

public interface IInterface {}
public class A : IInterface {}
public class B : IInterface {}
public record InterfaceArrayFactory(A A, B B) : IFactory<IInterface[]>
{
    public IInterface[] Create()
    {
        var array = ArrayPool<IInterface>.Shared.Rent(2);
        array[0] = A;
        array[1] = B;
        return array;
    }
    public void Release(IInterface[] instance)
    {
        ArrayPool<IInterface>.Shared.Return(instance);
    }
}

[Register(typeof(A))]
[Register(typeof(B))]
[RegisterFactory(typeof(InterfaceArrayFactory))]
public partial class Container : IContainer<IInterface[]> { }

Whilst a factory doesn't have to be a record, doing so significantly shortens the amount of code you have to write.

The scope of the factory and the factory target is controlled separately. This allows you to e.g. have a singleton factory, but call CreateAsync on every resolution:

[RegisterFactory(typeof(InterfaceArrayFactory), scope: Scope.SingleInstance, factoryTargetScope: Scope.InstancePerResolution, typeof(IFactory<IInterface[]>))]

If a factory implements IFactory<T> for multiple Ts it will be registered as a factory for all of them.

A factory method can be generic. All of the type parameters must be used in the return type. When resolving a type StrongInject will first look for non generic registrations which can resolve that type. If there are none, it will see if it can use any generic factory methods to resolve the type. For example this is how you could allow StrongInject to resolve an ImmutableArray:

public class ImmutableArrayModule
{
    [Factory] public static ImmutableArray<T> CreateImmutableArray<T>(T[] arr) => arr.ToImmutableArray();
}

Generic methods can also have constraints. StrongInject will ignore generic methods during resolution if the constraints do not match.

A decorator is a type which exposes a service by wrapping an underlying instance of the same service. Calls may pass straight through to the underlying service, or may be intercepted and custom behaviour applied. See https://en.wikipedia.org/wiki/Decorator_pattern.

You can register a type as a decorator using the [RegisterDecorator(type, decoratedType)] attribute.

Here is an example of how you could time how long a call took using the decorator pattern and stronginject.

using System;
using System.Diagnostics;
using StrongInject

public class Foo {}
public interface IService
{
    Foo GetFoo()
}

public class Service : IService
{
    public Foo GetFoo() => new Foo();
}

public class ServiceTimingDecorator : IService
{
    private readonly IService _impl;
    public ServiceTimingDecorator(IService impl) => _impl = impl;
    public Foo GetFoo()
    {
        var watch = Stopwatch.StartNew();
        var foo = _impl.GetFoo();
        watch.Stop;
        Console.WriteLine($"Getting foo took {watch.ElapsedMilliseconds} ms");
        return foo;
    }
}

[Register(typeof(Service), typeof(IService))]
[RegisterDecorator(typeof(ServiceTimingDecorator), typeof(IService))]
public class Container : IContainer<IService> {}

StrongInject will resolve an instance of Service, and then wrap it in an instance of ServiceTimingDecorator. Whenever anyone asks for an IService they will get an instance of ServiceTimingDecorator.

You can't specify the scope of a decorator, as its scope is the same as that of the type it wraps.

The decorator constructor must have exactly one parameter of the decorated type, but can have any other parameters as well so long as they are not of the decorated type.

Instances provided by delegate parameters are never decorated.

You can also define decorator factory methods, and even generic decorator factory methods via the [DecoratorFactoryAttribute]:

[Register(typeof(Service), typeof(IService))]
public class Container : IContainer<IService>
{
    [DecoratorFactory] IService CreateDecorator(IService service) => new ServiceTimingDecorator(service);
}

Generic decorator factory methods gives you a powerful way to intercept resolution. For example you could theoretically use Castle.DynamicProxy along with a generic decorator factory to log every service thats created, or time all calls to all services:

using Castle.DynamicProxy;
using StrongInject;
using System;
using System.Diagnostics;
using System.Threading;

public class Interceptor : IInterceptor
{
    public void Intercept(IInvocation invocation)
    {
        var stopwatch = Stopwatch.StartNew();
        invocation.Proceed();
        stopwatch.Stop();
        Console.WriteLine($"Call to {invocation.Method.Name} took {stopwatch.ElapsedMilliseconds} ms");
    }
}

public class Foo { }
public class Bar { }

public interface IService1
{
    void Frob();
    Foo GetFoo();
}

public interface IService2
{
    Bar UseBar(Bar bar);
}

public class Service1 : IService1
{
    public void Frob()
    {
        Thread.Sleep(10);
    }

    public Foo GetFoo()
    {
        Thread.Sleep(20);
        return new Foo();
    }
}

public class Service2 : IService2
{
    public Bar UseBar(Bar bar)
    {
        Thread.Sleep(30);
        return bar;
    }
}

[Register(typeof(Service1), typeof(IService1))]
[Register(typeof(Service2), typeof(IService2))]
public partial class Container : IContainer<IService1>, IContainer<IService2>
{
    private readonly IInterceptor _interceptor = new Interceptor();
    private readonly ProxyGenerator _proxyGenerator = new ProxyGenerator();

    [DecoratorFactory]
    T Time<T>(T t) where T : class
    {
        if (typeof(T).IsInterface)
        {
            return _proxyGenerator.CreateInterfaceProxyWithTarget(t, _interceptor);
        }
        else
        {
            return _proxyGenerator.CreateClassProxyWithTarget(t, _interceptor);
        }
    }
}

public class Program
{
    public static void Main()
    {
        var container = new Container();
        container.Run<IService1>(x =>
        {
            x.Frob();
            _ = x.GetFoo();
        });
        container.Run<IService2>(x => _ = x.UseBar(new Bar()));
    }
}

The above program will print something like:

Call to Service1.Frob took 20 ms
Call to Service1.GetFoo took 26 ms
Call to Service2.UseBar took 42 ms

You can register multiple decorators for a type, and they will all be applied. As of now there is no way to control in which order they are applied, but the order is deterministic.

If you register an [Instance] and don't want it decorated, you can use Options.DoNotDecorate: [Instance(Options.DoNotDecorate)].

What if you need to provide configuration for a registration at runtime? Or alternatively what if you need to integrate with an existing container?

We've already mentioned above that you can mark instance fields or properties on a container as [Instance]s. This allows you to access information only available at runtime during resolution:

using StrongInject;

public class A
{
    public A(Configuration configuration){}
}

public class Configuration {}

[Register(typeof(A))]
public partial class Container : IContainer<A>
{
    [Instance] Configuration _configuration;
    public Container(Configuration configuration) => _configuration = configuration;
}

In some cases the runtime fields you need might be of a type that you would be hesitant to register, such as bool, or string. In such cases you can use factory methods to only access them where appropriate:

using StrongInject;

public interface IInterface { }
public class A : IInterface { }
public class B : IInterface { }

[Register(typeof(A))]
[Register(typeof(B))]
public partial class Container : IContainer<IInterface>
{
    private readonly bool _useB;
    public Container(bool useB) => _useB = useB;

    [Factory]
    IInterface GetInterfaceInstance(Func<A> a, Func<B> b) => _useB ? b() : a();
}

In some cases though you need greater control over the disposal of the created instances. To do so you can make an Instance field implementing IFactory<T> or IAsyncFactory<T> and use Options.UseAsFactory. For example here's how you could integrate with Autofac:

using StrongInject;

public class A
{
    public A(B b){} 
}
public class B {}

public class AutofacFactory<T>(Autofac.IContainer autofacContainer) : IFactory<T> where T : class
{
    private readonly ConcurrentDictionary<T, Autofac.Owned<T>> _ownedDic = new();
    private readonly Autofac.IContainer _autofacContainer;
    public AutofacFactory(Autofac.IContainer autofacContainer) => _autofacContainer = autofacContainer;
    public T Create()
    {
        var owned = _autofacContainer.Resolve<Owned<T>>();
        _ownedDic[owned.Value] = owned;
        return owned.Value;
    };
    public void Release(T instance)
    {
        if (_ownedDic.TryGetValue(instance, out var owned))
            owned.Dispose();
    }
}

[Register(typeof(A))]
public partial class Container : IContainer<A>
{
    [Instance(Options.AsImplementedInterfacesAndUseAsFactory)] private readonly AutofacFactory<B> _autofacFactory;
    public Container(AutofacFactory<B> autofacFactory) => _autofacFactory = autofacFactory;
}

This registers AutofacFactory<B> as all implemented interfaces, namely IFactory<B>. Since this is a factory, this also becomes a registration for B as well.

Create is called once per resolution (equiavalent to Instance Per Resolution scope). This can be adjusted further by registering it as [Instance(Options.AsImplementedInterfacesAndUseAsFactory | Options.FactoryTargetScopeShouldBeSingleInstance) for example.

It is possible for there to be multiple registrations for a type. In such a case resolving an instance of the type will result in an error, unless there is a best registration. The rule for picking the best registration is simple - any registration defined by a module is better than registrations defined on other modules that that module imports.

So for example, imagine there is a Container, and two modules, ModuleA and ModuleB.

If all three define a registration for SomeInterface, then the one defined on the container will always be the best.

If just ModuleA and ModuleB define a registration for SomeInterface then things will depend:

• If Container imports both modules, resolving SomeInterface will always result in an error (even if ModuleA imports ModuleB or vice versa).
• If Container imports ModuleA, and ModuleA imports ModuleB, then ModuleA's registration will be best.
• If Container imports ModuleB, and ModuleB imports ModuleA, then ModuleB's registration will be best.

To fix errors as a result of multiple registrations for a type, the simplest thing to do is to add a single best registration directly to the container. If the container already has multiple registrations for the type, then move those registrations to a seperate module and import them.

StrongInject can automatically resolve non-void reurning delegates even if they're not registered. It tries to resolve the return type. The delegate parameters can be used in the resolution, and will override any existing resolutions.

There are two reasons you might want to use delegate resolution:

1. To return a new instance of the return type on every call:

using System;
using StrongInject;

public class A
{
  public A(Func<B> fB) => Console.WriteLine(fB() != fB()); //prints true
}

public class B{}

[Register(typeof(A))]
[Register(typeof(B))]
public class Container : IContainer<A> {}

2. To provide parameters which are not available at resolution time:

using System;
using StrongInject;

public class Server
{
  private Handler _frobbingHandler;
  private Handler _nonFrobbingHandler;
  public Server(Func<bool, Handler> handlerFunc) => (_frobbingHandler, _nonFrobbingHandler) = (handlerFunc(true), handlerFunc(false));
  
  public bool HandleRequest(Request request, bool shouldFrob) => shouldFrob ? _frobbingHandler.HandleRequest(request) : _nonFrobbingHandler.HandleRequest(request);
}

public class Handler
{
  public Handler(bool shouldFrob) => ...
}

[Register(typeof(Server))]
[Register(typeof(Handler))]
public class Container : IContainer<Server> {}

If the return type can only be resolved asynchronously (see below), the delegate must return Task<T> or ValueTask<T>. e.g.

using System;
using StrongInject;
using System.Threading.Tasks;

public class Server
{
  private Func<bool, Task<Handler>> _handlerFunc;
  public Server(Func<bool, Task<Handler>> handlerFunc) => _handlerFunc = handlerFunc;
  
  public async Task<bool> HandleRequest(Request request, bool shouldFrob) => (await _handlerFunc(shouldFrob)).HandleRequest(request);
}

public class Handler : IRequiresAsyncInitialization
{
  public Handler(bool shouldFrob) => ...
  public async ValueTask ResolveAsync() => ...
}

[Register(typeof(Server))]
[Register(typeof(Handler))]
public class Container : IContainer<Server> {}

If your type implements IRequiresInitialization, Initialize will be called after construction. Whilst this is only useful in a few edge cases for synchronous methods, IRequiresAsyncInitialization is extremely useful as constructors cannot be async. Therefore I'll leave an example of using this API for the section on async support.

Every interface used by StrongInject has an asynchronous counterpart. There's IAsyncContainer, IAsyncFactory and IRequiresAsyncInitialization.

You can resolve an instance of T asynchronously from an IAsyncContainer<T> by calling StrongInject.AsyncContainerExtensions.RunAsync. RunAsync has overloads allowing you to pass in sync or async lambdas. As such IAsyncContainer<T> is useful even if resolution is completely synchronous if usage is asynchronous.

It is an error resolving T in an IContainer<T> if it depends on an asynchronous dependency.

A type can implement both IContainer<T1> and IAsyncContainer<T2>. They will share single instance depdendencies.

Here is a full fledged example where data will be loaded from the database as part of resolution using IRequiresAsyncInitialization:

using StrongInject;
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

public interface IDb
{
    Task<Dictionary<string, string>> GetUserPasswordsAsync();
}

public class PasswordChecker : IRequiresAsyncInitialization, IAsyncDisposable
{
    private readonly IDb _db;

    private Dictionary<string, string> _userPasswords;

    private Timer _timer;

    public PasswordChecker(IDb db)
    {
        _db = db;
    }

    public async ValueTask InitializeAsync()
    {
        _userPasswords = await _db.GetUserPasswordsAsync();
        _timer = new Timer(async _ => { _userPasswords = await _db.GetUserPasswordsAsync(); }, null, 60000, 60000);
    }

    public bool CheckPassword(string user, string password) => _userPasswords.TryGetValue(user, out var correctPassword) && password == correctPassword;

    public ValueTask DisposeAsync()
    {
        return _timer.DisposeAsync();
    }
}

[Register(typeof(PasswordChecker), Scope.SingleInstance)]
public partial class Container : IAsyncContainer<PasswordChecker>
{
    private readonly IDb _db;

    public Container(IDb db)
    {
        _db = db;
    }

    [Factory]
    IDb GetDb() => _db;
}

public static class Program
{
  public static async Task Main(string[] args)
  {
    await new Container(new Db()).RunAsync(x => 
      Console.WriteLine(x.CheckPassword(args[0], args[1])
        ? "Password is valid"
        : "Password is invalid"));
  }
}

When resolving an array type, if there are no user provided registrations for the array type, the array will be created by resolving all registrations (including generic registrations) for the element type, and filling the array with these instances.

For example:

public class A : IInterface {}
public class B : IInterface {}
public interface IInterface {}

[Register(typeof(A), typeof(IInterface))]
[Register(typeof(B), typeof(IInterface))]
public class Container : IContainer<IInterface[]>

This will resolve an array containing an instance of type A and an instance of type B.

The contents of the array are arbitrary but deterministic. A new array is created for every dependency, so users are free to mutate it.

Note that duplicate registrations will be deduplicated, so in the following case:

public class A : IInterface {}
public interface IInterface {}

[Register(typeof(A), typeof(IInterface))]
[Register(typeof(A), typeof(IInterface))]
public class Container : IContainer<IInterface[]>

The array will contain 1 item, but in this case:

public class A : IInterface {}
public interface IInterface {}

[Register(typeof(A), typeof(IInterface))]
[Register(typeof(A), Scope.SingleInstance, typeof(IInterface))]
public class Container : IContainer<IInterface[]>

It will contain 2 items.

Once a call to Run or RunAsync is complete, any Instance Per Resolution or Instance Per Dependency instances created as part of the call to Run or RunAsync will be disposed.

Similiarly when an Owned<T> is disposed, any Instance Per Resolution or Instance Per Dependency instances created as part of resolving T will be disposed.

In RunAsync/ResolveAsync if the types implement IAsyncDisposable it will be preferred over IDisposable. Dispose and DisposeAsync will not both be called, just DisposeAsync. In Run/Resolve, IAsyncDisposable will be ignored. Only Dispose will ever be called.

Since IFactory<T> is free to create a new instance every time or return a singleton, StrongInject cannot call dispose directly. Instead it calls IFactory<T>.Release(T instance). The factory is then free to dispose the class or not. When referencing the .NET Standard 2.1 package Release has a default implementation which does nothing. You only need to implement it if you want custom behaviour. If you reference the .NET Standard 2.0 package you will need to implement it either way.

Single Instance dependencies and their dependencies are disposed when the container is disposed. If the container implements IAsyncDisposable it must be disposed asynchronously even if it also implements IDisposable.

Note that dependencies may not be disposed in the following circumstances:

1. Resolution throws
2. Disposal of other dependencies throws.

StrongInject provides the following thread safety guarantees:

1. Resolution is thread safe, so long as it doesn't call back into the container recursively (e.g. a factory calling container.RunAsync).
2. If the container is disposed during resolution, then either dependencies will be created by the resolution, and will then be disposed, or resolution will throw and no dependencies will be created. Dependencies will not be created and then not disposed.
3. A SingleInstance dependency will never be created more than once.

StrongInject provides a number of inbuilt modules which can be used 'out of the box' in the StrongInject.Modules namespace for the most commonly required functionality. You still need to import these modules via RegisterModule, although you can get all of the less opinionated modules in one go by importing the StandardModule.

At the moment the following modules are provided:

1. LazyModule (registers Lazy<T>)
2. CollectionsModule (registers IEnumerable<T>, IReadOnlyList<T> and IReadOnlyCollection<T>)
3. ValueTupleModule (registers all tuples from sizes 2 till 10)
4. SafeImmutableArrayModule (registers ImmutableArray<T>)
5. UnsafeImmutableArrayModule (provides a faster non-copying registration for ImmutableArray<T> which cannot be used if a custom registration for T[] exists)

At the moment the StandardModule imports lazyModule, CollectionsModule and ValueTuple module.

If you would like more modules/registrations added please open an issue.

https://github.com/YairHalberstadt/stronginject/projects/1

This is currently in preview, meaning we can (and will) make API breaking changes. Now is the best time to file suggestions if you feel like the API could be approved.

Similiarly please do open issues if you spot any bugs.

Please feel free to work on any open issue and open a PR. Ideally open an issue before working on something, so that the effort doesn't go to waste if it's not suitable.

I tend to hang around on gitter so feel free to chat at https://gitter.im/stronginject/community#share.

You can also open an issue, ask on stackoverflow, or tag me on twitter.