dotnet-guidelines

What problem does it solve?

This Skill codifies C# coding guidelines and best practices to reduce bugs and improve maintainability across .NET projects.

Core Features & Use Cases

• Always use Primary Constructors for classes.
• Always prefer record types for immutable data structures.
• Never mix multiple classes or DTOs in a single file; filename MUST match the class/DTO name (e.g., UserDto.cs).
• Avoid private fields prefixed with _.
• Add a trailing period to all server-side log messages.
• Use string? for nullable strings.
• Use var for local variables when the type is obvious.
• Avoid Regions in code files.
• Use collection initializers and static lambdas when applicable.
• Always seal accessors for classes or records if not intended for inheritance.
• Always use internal for internal classes or records.
• Never inject HttpClient/IHttpClientFactory; use IRestClient.
• Never register services directly in IServiceCollection; use ITransientService, IScopedService, or ISingletonService.
• Always use ILogger with structured logging.
• Always use cancellation tokens for asynchronous methods.
• Always use IMemoryCore for time-based in-memory caching.
• Always use DTOs for API communication, validated with attributes.
• Always name lambda parameters with x.
• Never use try-catch blocks solely to log and rethrow exceptions.
• If backend changes are made, run dotnet build to ensure no errors.

Quick Start

Review a .cs file (e.g., UserService.cs) to verify primary constructors, immutable DTO usage, and absence of Regions; propose concrete fixes.