winforms

Instructions for restoring and building the WinForms repository. Use when asked how to restore NuGet packages, build the full solution, build a single project, create packages, or troubleshoot build errors.

Instructions for downloading and installing .NET preview runtime versions required by the WinForms repository. Use when test executables fail with "framework not found" errors or when a specific .NET preview runtime version needs to be installed.

Instructions for running unit tests, integration tests, and individual tests in the WinForms repository. Use this when asked how to run tests, filter them, use Visual Studio workflows, or troubleshoot test failures.

Instructions for modernizing and refactoring existing C# / VB.NET code files. Use when asked to refactor, modernize, clean up, review, or improve existing source files in this repository. Covers upgrading to C# 14 / .NET 10 idioms, comment quality, spelling and grammar fixes, XML documentation, and readability improvements.

C# and .NET coding standards for generating new code files. Use when creating new classes, methods, controls, tests, or any new C# / VB source files in this repository. Covers C# 14 / .NET 10 patterns, naming, formatting, XML docs, WinForms conventions, and performance idioms.

Instructions for writing unit tests for Graphics, Bitmap, GraphicsPath, and Font rendering APIs in System.Drawing. Covers bitmap-based verification, integer/float overload testing, version-guarded test blocks, and FluentAssertions patterns for path-point validation.

Instructions for adding new public APIs (properties, methods, events, delegates) to existing WinForms controls or components. Covers API issue tracking, PublicAPI file maintenance, property/event conventions, CodeDOM serialization, design-time attributes, and XML documentation.

Instructions for using GDI, GDI+ for drawing primitives, shapes and processing/rendering bitmaps and rendering Fonts. Also, tenets for adding new APIs to System.Drawing for modernization and improving drawing, imaging, and font features.

Instructions for writing unit tests for new public APIs on WinForms controls and components. Covers test project structure, naming conventions, property tests, event tests, OnXxx method tests, SubControl patterns, data attributes, and handle-state verification.