implementing-repository-pattern

Define an interface like IUserRepository with async CRUD methods, then create a concrete implementation such as UserRepository. Register the pair in the DI container with services.AddSingleton and inject it into a Service class via the constructor.

The Repository layer handles only data access operations against a data source, while the Service layer contains business logic and calls the repository. This separation keeps business rules independent of storage details and improves testability.

In Prism 9, override RegisterTypes in your PrismApplication and call containerRegistry.RegisterSingleton<IUserRepository, UserRepository>(). Modules can also register their own repositories inside their RegisterTypes method.

A generic IRepository<T> with standard CRUD methods reduces duplication when many entities share the same operations. For entities with specialized queries, prefer dedicated interfaces like IUserRepository to keep contracts explicit.

Avoid it for trivial applications where an ORM like Entity Framework already abstracts data access, since adding another layer only adds indirection. It is most valuable when you need testability, multiple data sources, or complex business logic separation.