Microsoft’s .NET 10 arrives in first preview

Microsoft has rolled out the first preview of.NET 10, a major new version of the company’s flagship software development platform. Likely to arrive as a production release in November,.NET 10 introduces C# 14 and adds major enhancements to the.NET runtime, SDK, libraries, ASP.NET Core, Blazor, and.NET MAUI, the company said.

Unveiled February 25,.NET 10 Preview 1 can be downloaded from dotnet.microsoft.com.

Enhancements arriving with C# 14 include first-class support for System.Span and System.ReadOnlySpan in the language. This involves new implicit conversions that allow more natural programming with these types, Microsoft said. This support boosts performance with no risk to safety. Also in C# 14, the argument to nameof can be an unbound generic type. C# 14 also lets developers add parameter modifiers such as scoped, ref, in, or out, or ref readonly to lambda expression parameters without specifying the parameter type.

For the.NET 10 runtime, reducing the abstraction overhead of popular language features is a key focus area for.NET 10. To pursue this goal, Microsoft has expanded the JIT (just in time) compiler’s ability to de-virtualize method calls to cover array interface methods. Also in the runtime, the JIT will stack-allocate small, fixed-sized arrays of value types that do not contain garbage collection pointers when it can guarantee the object will not outlive its parent method.

For.NET 10 libraries, APIs are being introduced that work with spans of characters, expanding normalization beyond string types and helping to avoid unnecessary allocations. APIs for making left-handed transformation matrices have been added for billboard and constrained billboard matrices, and improvements have been made to ZipArchive to improve performance and memory usage..NET 10 follows last November’s release of.NET 9. Other new features and improvements in.NET 10 Preview 1:

The F# language features better handling of generic unmanaged structs and adds a type conversions cache, only enabled for compiler runs.

For the.NET 10 SDK, a NuGet Audit feature now can prune framework-provided package references not used by the project.

Visual Basic adds unmanaged constraint support. The Visual Basic compiler also now respects the OverloadResolutionPriorityAttribute used to resolve ambiguities among method overloads. This means that new, faster Span-based overloads now are preferred by the compiler.

ASP.NET Core adds support for generating OpenAPI 3.1 documents. OpenAPI 3.1 is a significant update to the OpenAPI specification, with full support for JSON Schema draft 2020-12, Microsoft said. OpenAPI documents also now can be generated in the YAML format.

The RouteAttribute in Blazor now supports route syntax highlighting to help visualize the structure of the route template.

For Entity Framework,.NET 10 adds first-class LINQ support for the LeftJoin method, making those queries simpler to write, according to Microsoft.

 In.NET 10,.NET MAUI ships as a.NET workload and multiple NuGet packages, allowing developers to easily pin projects to specific versions and to easily preview unreleased or experimental builds, Microsoft said.