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Pre IL Code Generation


this feature requires Unity 2019.3 or later.

VContainer has the ability to perform the meta programming part faster by generating IL code at compile time. As a result, there is no reflection at runtime, and it is expected to be 3-6x faster. It works in the IL2CPP environment.

With VContainer, for example, the following code (as IL) is automatically generated:

class ClassA
private sealed class __GeneratedInjector : IInjector
public object CreateInstance(IObjectResolver resolver, IReadOnlyList<IInjectParameter> parameters)
I6 fromConstructor = resolver.ResolveOrParameter<I6>("fromConstructor1", parameters);
I7 fromConstructor2 = resolver.ResolveOrParameter<I7>("fromConstructor2", parameters);
return new ClassA(fromConstructor, fromConstructor2);
public void Inject(object instance, IObjectResolver resolver, IReadOnlyList<IInjectParameter> parameters)
ClassA clasA = (ClassA)instance;
I3 service = resolver.ResolveOrParameter<I3>("service3", parameters);
I4 service2 = resolver.ResolveOrParameter<I4>("service4", parameters);
allInjectionFeatureService.MethodInjectable1(service, service2);
I5 service3 = resolver.ResolveOrParameter<I5>("service5", parameters);
I6 service4 = resolver.ResolveOrParameter<I6>("service6", parameters);
classA.MethodInjectable2(service3, service4);
classA.PrivatePropertyInjectable = resolver.Resolve<I2>();
classA.PublicPropertyInjectable = resolver.Resolve<I3>();
classA.privateFieldInjectable = resolver.Resolve<I4>();
classA.PublicFieldInjectable = resolver.Resolve<I5>();

How to enable code generation mode#

1. Add VContainer.EnableCodeGen asmdef to your references#

If you have asmdef in your project that refers to the following 2 asmdef, they are targets for IL weaving.

  • VContainer
  • VContainer.EnableCodeGen

2. Build your assembly#

The next time the specified assembly is compiled, VContainer will make changes to the compiled dll.

If it succeeds, it will be logged. For example:

VContainer code generation optimization for MyGame.dll 24 types (40.0355ms)


In Unity 2020.2 and later, the ILPostProcessor can no longer output logs. As a temporary measure, the above log is output as a warning, but it may be removed in the future.