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Tag: csharp

243 posts · Page 2 of 25

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.

2026-07-18 microsoft-agent-framework agent-skills ai-agents

How to Package Reusable Domain Expertise as an Agent Skill in .NET with the Microsoft Agent Framework

There is no single Skill type in the Microsoft Agent Framework, but you can package domain expertise as a reusable agent, reuse it in-process with AsAIFunction, and advertise it across frameworks as an A2A AgentSkill. Full walkthrough on Agent Framework 1.0 and .NET 11.

2026-07-17 aspnetcore dotnet-11 security

ASP.NET Core 11 Preview 6 turns on automatic CSRF protection

Preview 6 rejects unsafe cross-origin browser requests by default, reading the Sec-Fetch-Site header instead of an antiforgery token. Here is what it blocks and how to opt out.

2026-07-17 errors csharp dotnet

Fix: System.InvalidOperationException: Headers are read-only, response has already started

You set a header, status code, or content type after the body was already flushed. Set all headers before the first write, or guard with HttpResponse.HasStarted and OnStarting.

2026-07-17 errors csharp dotnet

Fix: "The property could not be mapped, because it is not a supported primitive type or a valid entity type" in EF Core 11

EF Core hit a property it does not know how to store. Map it as a complex type, convert it with HasConversion, give it a key, or ignore it with [NotMapped].

2026-07-14 csharp dotnet dotnet-11

How to add response compression to an ASP.NET Core 11 API

A complete guide to response compression in ASP.NET Core 11: AddResponseCompression and UseResponseCompression, the new built-in Zstandard provider alongside Brotli and Gzip, compression levels, EnableForHttps and the CRIME/BREACH risk, custom MIME types, middleware ordering, and when to let the reverse proxy do it instead.

2026-07-14 csharp dotnet dotnet-11

How to return a typed Results<T1, T2> union from a minimal API endpoint in ASP.NET Core 11

Declare the handler's return type as Results<Ok<T>, NotFound> and return TypedResults.Ok / TypedResults.NotFound: the union gives compile-time checking that the handler only returns what it declares, and it self-describes to OpenAPI so you never write .Produces by hand. Covers async handlers, the six-type limit, and testing in ASP.NET Core 11.

2026-07-12 csharp dotnet dotnet-11

How to add output caching to a minimal API in ASP.NET Core 11

A complete, working guide to output caching in an ASP.NET Core 11 minimal API: AddOutputCache and UseOutputCache, CacheOutput on endpoints and MapGroup, named and base policies, Expire, VaryByQuery and VaryByHeader, tag-based eviction with EvictByTagAsync, cache stampede protection, ETag revalidation, and a Redis backing store.

2026-07-12 csharp dotnet dotnet-11

How to customize the OpenAPI document with AddOperationTransformer and AddSchemaTransformer in ASP.NET Core 11

A deep dive into the built-in OpenAPI transformer pipeline in .NET 11: operation vs schema transformers, the context objects, execution order, DI-activated transformers, and recipes for headers, responses, examples, and per-property tweaks.

2026-07-11 dotnet-11 csharp async

.NET 11 Runtime Async Drops the EnablePreviewFeatures Flag

As the .NET 11 previews progress toward the November release, Runtime Async has graduated: net11.0 projects opt in with a single MSBuild property, and the runtime libraries themselves now ship compiled on it.