Tema: csharp

• .NET: convenções de injeção de dependências — lifetimes, scopes e a armadilha da dependência cativa

  O Microsoft.Extensions.DependencyInjection regista serviços num IServiceCollection com lifetime transient, scoped ou singleton, e injeta-os através de construtores públicos. As regras documentadas são: nunca injetar um serviço scoped num singleton, deixar o container libertar (dispose) o que ele próprio criou, evitar chamadas ao estilo service locator, e validar os scopes para que as dependências cativas falhem no arranque, em vez de deixarem escapar estado entre pedidos.

  article · pt · unreviewed · conhecimento em 2026-09-16

• Writing a unit test in JUnit 5 and xUnit.net: annotations, lifecycle and parameterised cases side by side

  JUnit Jupiter marks tests with @Test, runs @BeforeEach and @AfterEach around each one on a fresh instance by default, and drives data-driven cases with @ParameterizedTest plus a source annotation; xUnit.net uses [Fact], the constructor and IDisposable for per-test setup on a fresh instance, [Theory] with [InlineData] for cases, and fixtures for shared expensive context. Writing tests with the same shape in both keeps a polyglot team's conventions aligned.

  methodology · en · unreviewed · conhecimento em 2026-09-16

• C# async/await pitfalls: sync-over-async, async void and ConfigureAwait

  The classic mistakes in C# asynchronous code are blocking on a Task with .Result, .Wait() or GetAwaiter().GetResult() (deadlocks under a single-threaded SynchronizationContext, thread-pool starvation on servers), async void methods whose exceptions cannot be caught, and misplacing ConfigureAwait(false), which belongs in general-purpose libraries and not in application code.

  article · en · unreviewed · conhecimento em 2026-09-16

• Pinning NuGet dependencies: PackageReference, central package management and packages.lock.json

  NuGet resolves the lowest applicable version of each package at restore time, so a restore can drift when new versions or floating ranges appear; a repeatable build declares versions once in Directory.Packages.props, enables RestorePackagesWithLockFile so packages.lock.json records the full closure, commits the lock file for applications, and restores with --locked-mode in CI.

  methodology · en · unreviewed · conhecimento em 2026-09-16

• Nullable reference types in C#: a compile-time contract, not a runtime check

  With <Nullable>enable</Nullable> the C# compiler treats string as non-nullable and string? as nullable, tracks the null-state of every expression and warns on mismatches; nothing changes at run time, string and string? are the same type, and the null-forgiving operator ! plus the nullable-analysis attributes ([NotNullWhen], [MemberNotNull]) are how you tell the compiler what it cannot infer.

  article · en · unreviewed · conhecimento em 2026-09-16

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