Windows XAML Developer

Overview

This skill provides best practices, architectural patterns, and library recommendations for building high-quality Windows desktop applications using XAML-based frameworks (WinUI 3 and WPF). It emphasizes the Model-View-ViewModel (MVVM) pattern, Dependency Injection (DI), and modern C# features.

When to Use

• •When generating code for Windows desktop applications (WinUI 3, WPF, UWP).
• •When structuring a new Windows XAML project.
• •When implementing the MVVM pattern.
• •When troubleshooting XAML binding or UI responsiveness issues.

Core Principles

1. •MVVM First: Always separate UI logic (View) from business logic (ViewModel). Avoid code-behind (.xaml.cs) except for pure UI concerns (e.g., window manipulation).
2. •Dependency Injection: Use DI to manage services and ViewModels. Avoid static singletons for testability.
3. •Responsive UI: Never block the UI thread. Use async/await for I/O and heavy computations.
4. •Modern Tooling: Leverage Roslyn source generators (e.g., CommunityToolkit.Mvvm) to reduce boilerplate.
5. •Build Integrity: When refactoring code into Shared Projects or Class Libraries, ALWAYS:
   • •Update the .csproj of the consumer projects to exclude the source files if they were previously included via wildcards (e.g., <Compile Remove="SharedLib\**" />).
   • •Run dotnet clean followed by dotnet build on the entire solution to ensure no stale artifacts or duplicate attribute errors remain.

Recommended Tech Stack

Frameworks

• •Primary: WinUI 3 (Windows App SDK) - The modern, native UI stack for Windows. Best for new applications.
• •Secondary: WPF (.NET 8/9) - Mature, stable ecosystem. Best for complex enterprise apps or when specific third-party controls are needed.

Essential Libraries

Project Structure

Organize the solution to enforce strict separation of concerns:

MyWindowsApp/
├── App.xaml                 # Application entry & DI composition root
├── Views/                   # XAML Windows, Pages, and UserControls
├── ViewModels/              # C# ViewModels (one per View)
├── Models/                  # Domain entities and data structures
├── Services/                # Business logic and data access interfaces/implementations
├── Converters/              # IValueConverter implementations
└── Assets/                  # Images, fonts, and resources