UJect

Uject is an attempt at a simplified dependency injection framework for Unity3d Games.

How to use

At its simplest, you can use a DiContainer as a dictionary of interfaces to concrete instances:

public class SampleClass
{
    //Create a new container
    private DiContainer container = new DiContainer("MyContainer");
    
    public SampleClass()
    {
        //Bind IInterface to an existing instance of impl
        var impl = new Impl();
        container.Bind<IInterface>().ToInstance(impl);

        //Retrieve from the container
        var dependency = container.Get<IInterface>();
    }

    private interface IInterface {}
    private class Impl : IInterface {}
}

Binding

Basic Bindings

UJect provides a simple binding interface for a few different use cases:

1. Bind to existing instance

        //Bind IInterface to an existing instance of impl
        var impl = new Impl();
        container.Bind<IInterface>().ToInstance(impl);

2. Bind to a new instance

        //Bind IInterface to a new instance of impl
        container.Bind<IInterface>().ToNewInstance<Impl>();

3. Bind to factory

        //Bind IInterface to a new instance, which will be created by the factory at resolution time
        IInstanceFactory<Impl> myFactory = ...;
        container.Bind<IInterface>().ToFactory(myFactory);

4. Bind to factory method

        //Bind IInterface to a new instance, which will be created by the factory method at resolution time
        Func<Impl> myFactoryFunc = ...;
        container.Bind<IInterface>().ToFactoryMethod(myFactoryFunc);

5. [Experimental] Bind to a Resource

        //Bind IInterface to a Unity resource (from a Resources folder)
        container.Bind<IInterface>().ToResource("MyResources/ImplAsset");

Unbinding

You can unbind by calling

        container.Unbind<IInterface>();

Custom IDs

Sometimes, you want to bind multiple instances of the same interface. In that case, you can give bind each with a custom string id:

        var impl1 = new Impl();
        var impl2 = new Impl();
        container.Bind<IInterface>().WithId("InstanceA").ToInstance(impl1);
        container.Bind<IInterface>().WithId("InstanceB").ToInstance(impl2);

They can be retrieved in a similar manner:

        var dependency1 = container.Get<IInterface>("InstanceA");
        var dependency2 = container.Get<IInterface>("InstanceB");

Injection

Because calling Get<TInterface>() everywhere is annoying, UJect comes with an [Inject] attribute, which can be used to automatically inject dependencies into other classes via reflection.

public class SampleClass
{
    //Create a new container
    private DiContainer container = new DiContainer("MyContainer");
    
    public SampleClass()
    {
        container.Bind<IInterface>().ToNewInstance<Impl>();
        container.Bind<IInterface2>().ToNewInstance<Impl2>();

        //Retrieve from the container
        var dependency = container.Get<IInterface>();
    }

    private interface IInterface {}
    private class Impl : IInterface 
    {
        [Inject] private readonly IInterface2 impl2;
    }
    
    private interface IInterface2 {}
    private class Impl2 : IInterface2 {}
}

In this example, impl2 will be automatically injected into the Impl instance when IInterface is resolved.