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Tag: csharp-15

4 posts

2026-07-18 dotnet-11 csharp csharp-15

C# 15 Extension Indexers Round Out Extension Members in .NET 11 Preview 6

Extension indexers landed in .NET 11 Preview 6, letting you add this[...] access to types you do not own. They complete the extension members story that started with methods and properties in C# 14.

2026-06-21 csharp dotnet csharp-15

C# 15 Closed Class Hierarchies: The closed Keyword in .NET 11 Preview 5

C# 15 adds the closed modifier in .NET 11 Preview 5, giving class hierarchies compile-time exhaustiveness in switch expressions. Here is how it works and the one gotcha.

2026-04-13 csharp-15 dotnet-11 collection-expressions

C# 15 Collection Expression Arguments: Pass Constructors Inline with with(...)

C# 15 adds the with(...) element to collection expressions, letting you pass capacity, comparers, and other constructor arguments directly in the initializer.

2026-04-08 csharp dotnet csharp-15

C# 15 Union Types Are Here: Type Unions Ship in .NET 11 Preview 2

C# 15 introduces the union keyword for type unions with exhaustive pattern matching and implicit conversions. Available now in .NET 11 Preview 2.