dotnet-patterns

Use async all the way by returning Task from methods and awaiting calls instead of blocking with .Result or .Wait(). Always accept and pass a CancellationToken, and use Task.WhenAll to run independent operations concurrently.

The Result pattern returns an explicit success or failure object instead of throwing exceptions for expected failures like validation errors. Use it for business-rule failures while reserving exceptions for truly exceptional conditions.

Define an interface such as IOrderRepository with async methods accepting CancellationToken, then implement it using AppDbContext with AsNoTracking for read queries. Register the implementation with AddScoped in the DI container.

Blocking on async code with .Result or .Wait() risks thread starvation and deadlocks under load. The fix is to make the entire call chain async and await each operation instead of synchronously blocking.

Use records for immutable value objects and DTOs where equality is value-based, and init-only properties for immutable request models. Reserve mutable classes with public setters for cases where mutation is an explicit, justified choice.