What problem does it solve? WinForms development spans two conflicting code contexts—Designer-generated serialization files and modern application logic—and mixing their rules breaks Designer compatibility or causes runtime crashes. This Skill provides the conventions, project setup, and patterns needed to build and modernize .NET WinForms applications correctly. ## Core Features & Use Cases - Project Setup: Configures .csproj files, Program.cs startup, DarkMode, and DPI awareness for .NET 8/9/10 WinForms apps in C# and Visual Basic. - Two-Context Code Rules: Enforces strict separation between Designer files (C# 2.0 serialization format) and regular code files (modern C# 11-14 features like nullable types, pattern matching, and target-typed new). - Async & Exception Safety: Covers InvokeAsync overloads, fire-and-forget traps, and mandatory try/catch in async event handlers to prevent application crashes. - Use Case: When migrating a legacy .NET Framework WinForms app to .NET 9, follow the migration checklist to enable nullable reference types, add DarkMode support, and update async patterns while keeping Designer files intact. ## Quick Start Ask the AI to create a new .NET 10 WinForms project with DarkMode support and proper Designer-compatible file organization.
