.NET Core Expert

Purpose

Provides expertise in cross-platform .NET development, including .NET MAUI for mobile/desktop, cross-platform console applications, and cloud-native .NET services. Covers .NET 8 features and cross-platform deployment.

When to Use

Building cross-platform .NET applications
Developing with .NET MAUI (mobile/desktop)
Creating cross-platform console tools
Deploying .NET to Linux containers
Building cloud-native .NET services
Cross-platform file and process handling
Using .NET Native AOT compilation

Quick Start

Invoke this skill when:

Building cross-platform .NET applications
Developing with .NET MAUI
Creating cross-platform console tools
Deploying .NET to Linux containers
Using .NET Native AOT compilation

Do NOT invoke when:

Windows-only WPF/WinForms (use windows-app-developer)
Legacy .NET Framework (use dotnet-framework-4.8-expert)
Web APIs specifically (use csharp-developer)
Azure infrastructure (use azure-infra-engineer)

Decision Framework

Cross-Platform UI:
├── Mobile + Desktop → .NET MAUI
├── Desktop only → Avalonia or MAUI
├── Web → Blazor
└── Console → Cross-platform console app

Deployment Target:
├── Linux containers → Self-contained, Alpine
├── Windows service → Worker service
├── macOS app → .NET MAUI or Avalonia
├── Single file → Publish single-file
└── Fast startup → Native AOT

Core Workflows

1. .NET MAUI App Setup

Create MAUI project from template
Configure target platforms
Set up MVVM architecture
Implement platform-specific code
Add handlers for native features
Configure app lifecycle
Test on each platform

2. Cross-Platform Deployment

Configure RuntimeIdentifiers
Choose self-contained or framework-dependent
Set up trimming if needed
Handle platform-specific paths
Package for each platform
Test on target OS

3. Native AOT Compilation

Enable PublishAot in project
Review AOT compatibility
Handle reflection limitations
Test trimmed application
Verify startup performance
Deploy optimized binary

Best Practices

Use Path.Combine for cross-platform paths
Check RuntimeInformation.IsOSPlatform
Use conditional compilation sparingly
Test on all target platforms
Use cross-platform abstractions
Handle line endings properly

Anti-Patterns

| Anti-Pattern | Problem | Correct Approach | |--------------|---------|------------------| | Windows paths | Breaks on Linux/Mac | Use Path.Combine | | P/Invoke everywhere | Platform-specific | Use cross-platform APIs | | Ignoring case sensitivity | Fails on Linux | Consistent casing | | Untested on targets | Runtime failures | CI for each platform | | Heavy reflection with AOT | Trimming breaks app | Use source generators |