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.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:

And meet his better looking slnx brother instead:

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!