csharp-dev

name	csharp-dev
description	C# and .NET development workflow for building, testing, debugging, and maintaining .NET applications. Use when working with .NET, .NET Core, ASP.NET, Blazor, WPF, WinUI, or any C# project. Triggers: dotnet build, dotnet run, dotnet test, csproj, NuGet, package restore, debugging C#, memory issues, async patterns.
user-invocable	true

C# Development

When to Use This Skill

• Building, running, or testing .NET applications
• Working with .NET projects (csproj, sln files)
• NuGet package management
• Debugging C# applications
• ASP.NET Core, Blazor, WPF, WinUI, or console apps
• Async/await patterns, Tasks, concurrency
• Memory profiling or performance issues
• Entity Framework, LINQ questions

Common Workflows

Building Projects

# Build entire solution
dotnet build <solution.sln>

# Build specific project
dotnet build <project.csproj>

# Build with configuration
dotnet build <project.csproj> -c Release

# Build for specific runtime
dotnet build <project.csproj> -r win-x64

Running Projects

# Run console app
dotnet run --project <project.csproj>

# Run with arguments
dotnet run --project <project.csproj> -- --arg1 value

# Run in watch mode (for development)
dotnet watch run --project <project.csproj>

Testing

# Run all tests
dotnet test

# Run tests with coverage
dotnet test --collect:"XPlat Code Coverage"

# Run specific test project
dotnet test <test.csproj>

# Run tests matching pattern
dotnet test --filter "FullyQualifiedName~TestClassName"

NuGet Package Management

# Add package
dotnet add <project.csproj> package <PackageName>

# Add specific version
dotnet add <project.csproj> package <PackageName> --version <version>

# Remove package
dotnet remove <project.csproj> package <PackageName>

# List packages
dotnet list <project.csproj> package

Project Structure Conventions

Item	Location
Solution file	.sln in root
Project file	.csproj in project folder
Source code	src/ or project root
Tests	tests/ or *.Tests/
NuGet packages	packages/ or global cache
Build output	bin/Debug or bin/Release

Key File Patterns

• *.csproj - Project file (SDK style preferred)
• *.sln - Solution file
• Directory.Build.props - MSBuild properties shared across projects
• Directory.Build.targets - MSBuild targets shared across projects
• global.json - SDK version pinning
• nuget.config - NuGet sources configuration

Project Type Detection

Check the <Project Sdk=""> attribute in csproj files:

• Microsoft.NET.Sdk - Modern .NET SDK project
• Microsoft.NET.Sdk.Web - ASP.NET Core web app
• Microsoft.NET.Sdk.Razor - Blazor/Razor
• Microsoft.NET.Sdk.Windows - WPF/WinUI/Windows desktop

Async Patterns in C#

// Proper async pattern
public async Task<Result> DoSomethingAsync()
{
    await Task.Delay(100);
    return Result.Success;
}

// CancellationToken usage
public async Task DoWorkAsync(CancellationToken ct)
{
    for (int i = 0; i < 10; i++)
    {
        ct.ThrowIfCancellationRequested();
        await ProcessAsync(i, ct);
    }
}

// Parallel execution
var tasks = items.Select(async item => await ProcessAsync(item));
var results = await Task.WhenAll(tasks);

Debugging Tips

1. Attach to process: Debug > Attach to Process (Ctrl+Alt+P)
2. Breakpoints: F9 toggle, conditional breakpoints supported
3. Immediate window: Evaluate expressions during debug
4. Watch window: Monitor variables/expressions
5. Launch profiles: Configure in launchSettings.json

Common Issues & Solutions

Issue	Solution
"Could not find dotnet SDK"	Check global.json version, verify PATH
"Package restore failed"	Run dotnet restore with --verbosity detailed
"Ambiguous reference"	Check for duplicate using statements or package conflicts
"Missing Microsoft.NET.Sdk"	Add <Project Sdk="Microsoft.NET.Sdk"> to csproj
"Target framework not found"	Install the SDK/runtime for that framework

Resources

• C# documentation
• .NET documentation
• NuGet package reference