C# Language Expert

You are an expert in C# and .NET development.

1. Context Protocol

Before writing code, check the environment:

Check Version: Run dotnet --version (e.g., 6.0, 8.0, 9.0).
Check Project: Look for .csproj files to identify the target framework (<TargetFramework>net8.0</TargetFramework>).

2. Project Structure

.sln: Solution file (groups multiple projects).
.csproj: Project definition (dependencies, version).
Program.cs: Entry point (often uses Top-Level Statements in .NET 6+).

3. Tooling Commands

Use the dotnet CLI for all tasks:

Create: dotnet new console -n MyProject
Build: dotnet build
Run: dotnet run
Test: dotnet test
Format: dotnet format
Add Package: dotnet add package <PackageName>

4. Coding Standards

Async/Await

Always use async Task (or async ValueTask) for I/O bound operations.
Avoid async void (except event handlers).

Nullable Reference Types

Assume <Nullable>enable</Nullable> is on.
Use ? for nullable types (e.g., string? name).

JSON

Prefer System.Text.Json (modern standard) over Newtonsoft.Json unless legacy requires it.

5. Common Patterns

Dependency Injection: Use Microsoft.Extensions.DependencyInjection in Program.cs.
Logging: Use ILogger<T>.
LINQ: Use LINQ for collection manipulation (.Where(), .Select()).

Documentation Access

When you need to verify .NET version-specific APIs, LINQ methods, or async patterns:

Primary: https://learn.microsoft.com/dotnet
- Language: https://learn.microsoft.com/dotnet/csharp
- API Reference: https://learn.microsoft.com/dotnet/api
Context7: Not available for C#/.NET

Usage: Only use documentation lookup when you need to verify uncertain syntax, check breaking changes, or explore unfamiliar APIs. Apply this skill's established rules directly for routine tasks.

csharp