skills.rest
hdeshev
hdeshevCOMMUNITY
Explore all skills by this author →
WebsiteGitHub

modern-csharp

Write version-aware modern C# code compatible with the repository's target framework and LangVersion.

Updated May 2, 2026
Search Tags:#csharp#code review#refactoring#migration#dotnet#code modernization#langversion
One-click install
npx skills add https://github.com/hdeshev/pi-config --skill modern-csharp-hdeshev
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: modern-csharp
Source: https://github.com/hdeshev/pi-config/tree/main/agent/skills/modern-csharp
Command: npx skills add https://github.com/hdeshev/pi-config --skill modern-csharp-hdeshev

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve? It prevents C# code from using language features that the repository's target framework or LangVersion does not support, while guiding deliberate modernization toward idiomatic C# 12, 13, and 14 patterns. ## Core Features & Use Cases - Language Ceiling Detection: Inspects TargetFramework, LangVersion, and installed SDKs to determine which C# features are actually safe to use. - Modernization Guidance: Applies primary constructors, collection expressions, records, pattern matching, raw string literals, and C# 13/14 features only where the repo supports them. - Migration References: Provides before-and-after migration patterns from C# 8 through C# 14 with validation steps like dotnet build and dotnet test. - Use Case: When upgrading a .NET 9 service, use this Skill to safely adopt C# 13 features like params collections and System.Threading.Lock without breaking the build. ## Quick Start Ask the agent to review this C# repository and modernize the code using only features supported by its target framework and LangVersion.

Frequently Asked Questions about modern-csharp

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I know which C# features my .NET project supports?▼

Check the TargetFramework and LangVersion in your csproj or Directory.Build files. .NET 9 maps to C# 13 and .NET 10 maps to C# 14; newer language versions than the target framework supports are not supported.

How to migrate older C# code to modern syntax?▼

Migrate incrementally: start with non-breaking syntax updates like switch expressions and using declarations, then adopt records and primary constructors, then collection expressions. Verify each phase with dotnet build and dotnet test.

Can I use C# 14 features on .NET 9?▼

No. C# 14 is the stable language for .NET 10, while .NET 9 supports C# 13. Using a newer language version than the target framework supports is not supported and should not be forced via LangVersion.

Should I set LangVersion to latest or preview?▼

Avoid LangVersion=latest because it makes builds machine-dependent. Use preview only when the repository intentionally opts into preview features; otherwise rely on the default version implied by the target framework.

When should I avoid primary constructors in C#?▼

Keep traditional constructors when you need multiple overloads with complex logic, significant parameter validation, explicit field visibility, or constructor chaining in base classes. Primary constructors suit simple dependency capture scenarios.

Related Skills

Explore More Software Engineering Skills→
AGIBuildAGIBuild
10

dotnet-version-detection

Detect .NET TFMs and SDK versions from project files.

Community
Intermediate
s205109s205109
2

cck-verify

Verify .NET solution builds, tests, formatting, and git status before commits.

Community
Intermediate
angryconsultantangryconsultant

editorconfig

Generate a comprehensive .editorconfig file with coding style rules.

Community
Advanced
codewithmukeshcodewithmukesh
692

migrate

Guides EF Core schema migrations, .NET version upgrades, and NuGet package updates with rollback plans.

Official
Advanced