.SLN

Introduction

A .sln file is a Visual Studio solution: the list of projects that make up a piece of software, such as a C# .csproj or a C++ .vcxproj, with the build configurations they share, like Debug and Release for each platform. Opening the solution opens all its projects together, and building it builds them in the right order. The projects keep their own settings in their own files.

Software

• Visual Studio (Windows)
• JetBrains Rider (Windows, macOS, Linux)
• .NET SDK, whose dotnet build and dotnet sln read and change it (Windows, macOS, Linux)
• MSBuild (Windows, macOS, Linux)
• Visual Studio Code, with the C# Dev Kit extension (Windows, macOS, Linux)

Structure

A solution is a text file, usually saved as UTF-8 with a byte order mark. It opens with a line naming the format version, then comments and settings recording which Visual Studio wrote it. Each project has a Project block giving a GUID for the kind of project, its name, its path and its own GUID. A Global block follows, made of GlobalSection blocks: the solution’s configurations, how each one maps to each project’s configurations, and other settings.

Microsoft Visual Studio Solution File, Format Version 12.00
# Visual Studio Version 17
VisualStudioVersion = 17.0.31903.59
MinimumVisualStudioVersion = 10.0.40219.1
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "App", "App\App.csproj", "{6F1D3C42-...}"
EndProject
Global
	GlobalSection(SolutionConfigurationPlatforms) = preSolution
		Debug|Any CPU = Debug|Any CPU
		Release|Any CPU = Release|Any CPU
	EndGlobalSection
EndGlobal