C# 15: New features with code examples

C# 15 has been released with .NET 11 and it comes with new features. You can learn more about the new features in C# 15, or watch the video:

Download the code example

You'll need to fill out the code example form. We will send you an email where you can download the code example.

Software

This is the software that will need to be installed onto your machine.

• Visual Studio 2026. Version 18.12.0 or above. It will work with the free community version.

• .NET 11 SDK. Version 11.0.0 or above.

The application

Open up RoundTheCode.CSharp15.slnx.

There are two applications:

• Library shows all the new features in separate files.

• OtherLibrary has an example of the closed keyword. Uncomment the code in Library/02-ClosedTypes.cs to see the error you get if you inherit a type that has the closed keyword in another assembly.