Mini Dependency Injection Container?

Short answer: public class MyContainer { private Dictionary<Type, Type> map = new(); public void Register<TInterface, TImplementation>() { map[typeof(TInterface)] = typeof(TImplementation); } public TInterface Resolve<TInterface>() { var impl = map[typeof(TInterface)]; return (TInterface)Activator.CreateInstance(impl); } }

Example code

public class MyContainer
{
private Dictionary<Type, Type> map = new();
public void Register<TInterface, TImplementation>()
{
map[typeof(TInterface)] = typeof(TImplementation);
}
public TInterface Resolve<TInterface>()
{
var impl = map[typeof(TInterface)];
return (TInterface)Activator.CreateInstance(impl);
}
}

Real-world example (ShopNest)

Answer with: definition → one ShopNest-style story → trade-off → how you would verify it in production.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.