dotnet-fundamentals

name

dotnet-fundamentals

description

Applies modern .NET fundamentals — dependency injection, Options pattern, configuration, and modern C# idioms. Use when registering services in any .NET host (ASP.NET Core, Worker Service, Console, MAUI), binding configuration with IOptions<T>, choosing DI lifetimes, configuring appsettings.json / User Secrets / environment variables, or applying primary constructors, required properties, nullable reference types, and CancellationToken propagation.

Modern .NET Fundamentals

When to Use

• Working with .NET/C# Code
• Registering services in any IServiceCollection (ASP.NET Core, Worker Service, Console app, MAUI, library DI extension methods)
• Choosing a DI lifetime (Transient, Scoped, Singleton) or registering keyed services (.NET 8+)
• Binding configuration sections to a strongly-typed Options class
• Setting up appsettings.json, environment-specific overrides, User Secrets, or environment variables
• Adopting primary constructors, required properties, nullable reference types, or CancellationToken propagation in new code

Core Principles

• This skill is technology-agnostic across .NET hosts. ASP.NET Core, EF Core, and SDK builders all sit on top of these fundamentals.
• Interface-first registration — register services via their abstraction (AddScoped<IFoo, Foo>()), not the concrete type. Enables substitution and testing.
• No service locator — never inject IServiceProvider into business logic. Constructor-inject the dependencies you actually need.
• Options over constructor parameters for configuration — bind config sections to IOptions<T>, do not pass raw IConfiguration values around.
• Fail fast — use ValidateDataAnnotations().ValidateOnStart() so misconfiguration surfaces at startup, not at first use.
• Immutable configuration — Options classes use required properties and init-only setters.
• Cancellation flows everywhere — every async method takes a CancellationToken with default as its last parameter and forwards it.

Reference Index

• dependency-injection.md — IServiceCollection registration, lifetimes, keyed services, interface-based registration, anti-service-locator
• options-pattern.md — IOptions<T> vs IOptionsMonitor<T> vs IOptionsSnapshot<T>, BindConfiguration, ValidateDataAnnotations, ValidateOnStart
• configuration.md — appsettings.json and environment overrides, User Secrets, environment variables, production secret stores
• modern-patterns.md — primary constructors, required / init-only properties, nullable reference types, CancellationToken propagation

Related Skills

• dotnet-aspnet — Builds the HTTP layer (controllers, minimal APIs, middleware, routing, auth, ProblemDetails) on an ASP.NET Core host
• dotnet-sdk-builder — Generates .NET SDK / client libraries (DI extension methods, typed HTTP clients, typed Options, typed exceptions)
• dotnet-ef-core — Entity Framework Core data access (DbContext, entities, LINQ, migrations); registered via DI and configured via Options
• dotnet-reviewer — Structured .NET code review producing a severity-tagged Markdown report
• dotnet-tester — Writes and runs C#/.NET unit tests (xUnit, FakeItEasy, AwesomeAssertions) and identifies missing test cases
• dotnet-nuget-manager — Use whenever NuGet packages are added, removed, or updated in a project (dotnet CLI, central version management, version verification)