dotnet-guidelines

Enforce C# coding guidelines by applying standards for primary constructors, record types, file naming, nullable references, and access modifiers during code review. This Skill validates these practices against your codebase and proposes concrete fixes to improve consistency and maintainability.

C# best practices include using primary constructors for all classes, sealing accessors unless inheritance is intended, matching filenames to class names, avoiding private field prefixes, and using `internal` for internal classes. These conventions reduce bugs and improve code clarity.

Always use DTOs for API communication, validated with attributes, and place each DTO in its own file matching the class name. Prefer `record` types for immutable data structures and use `string?` for nullable strings to enforce type safety.

Never inject `HttpClient` or `IHttpClientFactory` directly; use `IRestClient`. Register services through `ITransientService`, `IScopedService`, or `ISingletonService` instead of directly in `IServiceCollection` to maintain consistency and testability.

Use `ILogger` with structured logging and add trailing periods to all server-side log messages. Always include cancellation tokens in asynchronous methods and use `IMemoryCore` for time-based in-memory caching to follow .NET conventions.

Never use try-catch blocks solely to log and rethrow exceptions, and avoid regions in code files entirely. These anti-patterns reduce readability; use proper logging practices and structured exception handling instead.