Snippet

Minimalistic Dependency Injection Container

Understanding the internals of frameworks is vital for expert developers. This snippet implements a basic IoC (Inversion of Control) container using a dictionary of factory delegates. It demonstrates how types are mapped to instantiation logic without relying on heavy external libraries.

snippet.cs

csharp

public class SimpleContainer
{
    private readonly Dictionary<Type, Func<object>> _factories = new();
 
    public void Register<T>(Func<T> factory) where T : class 
        => _factories[typeof(T)] = () => factory();
 
    public T Resolve<T>() where T : class 
        => (T)_factories[typeof(T)]();
}
 
// Usage
var container = new SimpleContainer();
container.Register<ILogger>(() => new ConsoleLogger());
var logger = container.Resolve<ILogger>();

Breakdown

Dictionary<Type, Func<object>>

Stores a mapping from an interface or class type to a function that creates its instance.

Saves a lambda expression that will be invoked whenever the type T is requested.

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Minimalistic Dependency Injection Container

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