.NET 9 - Goodbye sln!

Although the csproj file evolved and simplified a lot over time, the Visual Studio solution file (.sln) remained an ugly file format full of magic GUIDs. With the latest .NET 9 SDK(9.0.200), we finally got an alternative; a new XML-based solution file(.slnx) got introduced in preview.

So say goodbye to this ugly sln file:

	Microsoft Visual Studio Solution File, Format Version 12.00
	# Visual Studio Version 17
	VisualStudioVersion = 17.13.35825.156
	MinimumVisualStudioVersion = 10.0.40219.1
	Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TestProject1", "..\TestProject1\TestProject1.csproj", "{0CA151AB-72D3-47B3-902B-2008A79D3923}"
	EndProject
	Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "AICalculator", "AICalculator\AICalculator.csproj", "{86549BF8-C76C-C1FA-8562-3CCB90DB7837}"
	EndProject
	Global
	GlobalSection(SolutionConfigurationPlatforms) = preSolution
	Debug|Any CPU = Debug|Any CPU
	Release|Any CPU = Release|Any CPU
	Test|Any CPU = Test|Any CPU
	EndGlobalSection
	GlobalSection(ProjectConfigurationPlatforms) = postSolution
	{0CA151AB-72D3-47B3-902B-2008A79D3923}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
	{0CA151AB-72D3-47B3-902B-2008A79D3923}.Debug|Any CPU.Build.0 = Debug|Any CPU
	{0CA151AB-72D3-47B3-902B-2008A79D3923}.Release|Any CPU.ActiveCfg = Release|Any CPU
	{0CA151AB-72D3-47B3-902B-2008A79D3923}.Release|Any CPU.Build.0 = Release|Any CPU
	{0CA151AB-72D3-47B3-902B-2008A79D3923}.Test|Any CPU.ActiveCfg = Test|Any CPU
	{0CA151AB-72D3-47B3-902B-2008A79D3923}.Test|Any CPU.Build.0 = Test|Any CPU
	{86549BF8-C76C-C1FA-8562-3CCB90DB7837}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
	{86549BF8-C76C-C1FA-8562-3CCB90DB7837}.Debug|Any CPU.Build.0 = Debug|Any CPU
	{86549BF8-C76C-C1FA-8562-3CCB90DB7837}.Release|Any CPU.ActiveCfg = Release|Any CPU
	{86549BF8-C76C-C1FA-8562-3CCB90DB7837}.Release|Any CPU.Build.0 = Release|Any CPU
	{86549BF8-C76C-C1FA-8562-3CCB90DB7837}.Test|Any CPU.ActiveCfg = Test|Any CPU
	{86549BF8-C76C-C1FA-8562-3CCB90DB7837}.Test|Any CPU.Build.0 = Test|Any CPU
	EndGlobalSection
	GlobalSection(SolutionProperties) = preSolution
	HideSolutionNode = FALSE
	EndGlobalSection
	GlobalSection(ExtensibilityGlobals) = postSolution
	SolutionGuid = {C733AAA2-34BC-4EBA-8FC6-7E404EB05D41}
	EndGlobalSection
	EndGlobal

view raw Example.sln hosted with ❤ by GitHub

And meet his better looking slnx brother instead:

	<Solution>
	<Configurations>
	<BuildType Name="Debug" />
	<BuildType Name="Release" />
	<BuildType Name="Test" />
	</Configurations>
	<Project Path="../TestProject1/TestProject1.csproj" />
	<Project Path="AICalculator/AICalculator.csproj" />
	</Solution>

view raw Example.slnx hosted with ❤ by GitHub

To use this feature we first have to enable it:

• Go to Tools -> Options -> Environment -> Preview Features
• Check the checkbox next to Use Solution File Persistence Model

Now we can migrate an existing sln file to slnx using the following command:

dotnet sln migrate AICalculator.sln
.slnx file D:\Projects\Test\AICalculator\AICalculator.slnx generated.

Or create a new Visual Studio solution using the slnx format:

dotnet new sln --format slnx
The template "Solution File" was created successfully.

The new format is not yet recognized by VSCode but it does work in Jetbrains Rider:

 

Nice!