.NET 9 code example to download with its key new features
The .NET 9 release has seen a number of new features and you can download the code example to try them out for yourself.
Software
This is the software that will need to be installed onto your machine.
- Visual Studio 2022. Version 17.12.0 or above. It will work with the free community version.
- .NET 9 SDK. Version 9.0.0 or above.
Get the application working
You'll need to fill out the code example form. We will send you an email where you can download the code example.
Open up RoundTheCode.DotNet9NewFeatures.sln in Visual Studio 2022 and run the ASP.NET Core application which will be hosted on https://localhost:9992.
C# coding challenges
Our online code editor allows you to compile the answer.
This is how you can try out the new features:
New LINQ methods
Run either https://localhost:9992/api/linq/count-by, https://localhost:9992/api/linq/aggregate-by or https://localhost:9992/api/linq/index to test out the new LINQ methods.
Minimal API updates
Run https://localhost:9992/server-error to see the new InternalServerError method in the TypedResults static class.
The OpenAPI documentation that is produced when using ProducesProblem and ProducesValidationProblem can be viewed at https://localhost:9992/openapi/v1.json.
Developer exception page improvements
To see the new Endpoint Metadata section in the Routing tab on the developer exception page, run https://localhost:9992/api/error/error.
Keyed service support for middleware
Open up Middleware/MyMiddleware.cs to see keyed services being injected into a middleware class through the constructor and the Invoke method.
Static asset delivery optimisation
Publish the ASP.NET Core application and the publish folder will contain Gzip files .gz and Brotli .br files for the CSS and JavaScript files in the wwwroot folder.
OpenAPI document generation support
Load https://localhost:9992/openapi/v1.json to view the OpenAPI document with all the controller and Minimal API endpoints.
New HybridCache library
Run the https://localhost:9992/api/cache endpoint which uses the HybridCache library to cache the HTTP response from an external API call.
More information
Watch our .NET 9 new features video where you can see these new features and how they work.
And you can read our .NET 9 new features tutorial with explanations and examples of how each of them work.
Related pages
What's new in .NET 9? Key features you need to know!
Discover the latest updates in .NET 9. Explore new features, enhancements, and tools that you can use in your ASP.NET Core application right now!