# Layers: Models, Services, Controllers

Apps are split into layers (controllers, services, data access and models), each with one job, each handed the layer below it through its constructor.

![Cheat sheet: Layers: Models, Services, Controllers](https://fsdtrainingmedia.blob.core.windows.net/public/images/2026/11/43fbc0df8195492abf21939f2f29f9e0.webp)

- Category: C#
- Level: Journeyman
- Tags: Business Logic, c-sharp, Layered Architecture, OOP
- Updated: November 3, 2026

Source: https://www.ask-codey.com/cheat-sheets/dependency-injection-layers-models-services-controllers-cheat-sheet