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.NET Developer Setup

Covers C#, ASP.NET Core, WinForms, WPF, and MAUI. If you work primarily in Visual Studio and prefer a GUI-first workflow, this guide covers everything you need without requiring a terminal.

Terminal-free setup (Visual Studio only)​

If you live entirely inside Visual Studio and don't want a terminal, this is all you need:

1. Install GitHub Copilot in Visual Studio​

GitHub Copilot is built into Visual Studio 2022 version 17.10 and later. If you're on an older version, install it from Extensions → Manage Extensions → search "GitHub Copilot".

Sign in with your GitHub account in the Copilot panel. You need a GitHub Copilot subscription (Individual, Business, or Enterprise), separate from your Anthropic/Claude subscription.

What you get inside Visual Studio:

  • Inline completions: suggestions appear as you type, accept with Tab
  • Copilot Chat panel: open with View → GitHub Copilot Chat or Ctrl+\, Ctrl+C
  • Smart actions: right-click any selection for "Explain", "Fix", "Generate tests", "Generate docs"
  • Commit message generation: in the Git Changes window, click the Copilot sparkle icon

2. Use Copilot Chat effectively​

Open the chat panel and use it for anything you'd normally ask a colleague:

Explain what this method does and whether there are any edge cases I should handle.
Refactor this class to follow the repository pattern. The data access is currently
mixed into the controller - separate it into a service and a repository.
Generate xUnit tests for every public method in this class. Include tests for null
inputs and boundary values.
I'm getting this exception: [paste stack trace]. What is causing it and how do I fix it?

3. Designer-specific tips (WinForms / WPF / MAUI)​

The Visual Studio designer works visually - Copilot helps with the code behind it:

  • WinForms: Select any event handler stub the designer generated, right-click → Copilot → "Explain". Ask Copilot Chat to "fill in this Click handler to validate the form and call SaveCustomer()".
  • WPF: Paste a ViewModel stub and ask "Add INotifyPropertyChanged to every property in this class and implement RelayCommand for the Save and Cancel buttons."
  • MAUI: Ask "Convert this WPF ViewModel to work with MAUI - replace ICommand with RelayCommand from CommunityToolkit.Mvvm."
  • XAML: Copilot understands XAML. Select a block in the XAML editor and ask "Add a loading spinner that shows while IsLoading is true."

With a terminal (optional but recommended for ASP.NET Core / APIs)​

If you're building ASP.NET Core APIs, background services, or anything that runs dotnet commands, adding Claude Code gives you agentic multi-file tasks that Copilot can't do alone.

1. Install Node.js​

Claude Code is distributed via npm. Download Node.js 18+ from nodejs.org (Windows installer, no configuration needed).

Verify in a terminal (Command Prompt or PowerShell):

node --version   # should print v18.x or higher
npm --version

2. Install Claude Code​

npm install -g @anthropic-ai/claude-code

Open a terminal in your project folder and run:

cd C:\Projects\MyService
claude

3. Configure project context (CLAUDE.md)​

Create a CLAUDE.md file at the solution root. Claude Code reads it on every session:

# Project context

## Stack
- .NET 9, C# 13, ASP.NET Core (minimal API style)
- Entity Framework Core 9 with SQL Server
- MediatR for CQRS, FluentValidation for input validation
- xUnit + Moq for testing

## Conventions
- Follow MediatR request/handler pattern for all business logic
- Never put business logic in controllers - controllers only dispatch commands/queries
- Use record types for DTOs and command/query objects
- All public APIs must have XML doc comments
- Async all the way down - no .Result or .Wait()

## Commands
- `dotnet build` - build solution
- `dotnet test` - run all tests
- `dotnet run --project src/Api` - start API
- `dotnet ef migrations add MigrationName` - add EF migration

## Do not modify
- `src/Infrastructure/Migrations/` - managed by EF Core tooling

4. Claude Code tasks for .NET​

Generate a MediatR command and handler for creating a new Order. The handler
should validate the request with FluentValidation, persist via the repository,
and publish an OrderCreated domain event. Follow the pattern in
src/Application/Commands/CreateCustomer.cs.
Review my staged changes for async anti-patterns (.Result, .Wait(), async void)
and any EF Core queries that could cause N+1 problems.
Write xUnit tests for the CreateOrderCommandHandler. Mock the repository and event
publisher. Cover: happy path, validation failure, and repository exception.

Tips​

  • Copilot works well with C# idioms. It understands LINQ, async/await, nullable reference types, and pattern matching. Be explicit about which version of C# you're targeting if you need a specific feature.
  • For Copilot Chat: use #file references. In VS 2022 17.8+, type # in the chat panel to reference a specific file - this gives Copilot exact context without copy-pasting.
  • WinForms/WPF: don't ask AI to design the UI. The visual designer is faster for layout. Use AI for the logic behind it.
  • EF Core migrations: never auto-generate blindly. Always review generated migrations before applying. Ask Copilot to "explain what this migration does" if you're unsure.
  • NuGet packages: verify before adding. AI sometimes suggests outdated or renamed packages. Check nuget.org to confirm the current package name and version.