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Tag: csharp

347 posts · Page 13 of 35

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.

2026-07-11 dotnet performance jit

What is PGO in .NET and do I need to opt in?

PGO (profile-guided optimization) lets the .NET JIT specialize hot code for the types and branches your workload actually hits. Dynamic PGO has been on by default since .NET 8, so on .NET 8 and later you do not need to opt in. Here is what it does, how to see its effect, and the rare cases where you touch the knob.

2026-07-11 dotnet performance jit

What is tiered compilation and how do I reason about it?

Tiered compilation lets the .NET JIT compile every method twice: once fast and unoptimized to get your app running, then again with full optimizations once the runtime knows a method is hot. Here is how tier 0, tier 1, on-stack replacement, and Dynamic PGO fit together, and how to observe and tune them.

2026-07-10 dotnet aspnetcore csharp

What is the IHostedService contract and when do I use it?

IHostedService is the two-method interface (StartAsync/StopAsync) the .NET generic host calls on startup and graceful shutdown. Here is exactly what the contract promises, when to implement it directly, and the .NET 10 and 11 behavior changes that catch people out.

2026-07-09 dotnet trimming native-aot

What is trim-safe code and how do I write it?

Trim-safe code is code the .NET trimmer can statically prove is reachable, so it survives when unused code is removed from a self-contained app. This is the practical guide: turn on the analyzer, drive every IL2xxx warning to zero, annotate reflection with DynamicallyAccessedMembers, propagate RequiresUnreferencedCode to public APIs, and replace unanalyzable patterns with source generators.

2026-07-07 migration semantic-kernel microsoft-agent-framework

Migrate a Semantic Kernel App to Microsoft Agent Framework 1.0

A step-by-step checklist for moving an existing Semantic Kernel 1.77 .NET app to Microsoft Agent Framework 1.13. Covers the Kernel-to-AIAgent rewrite, plugins-to-tools, thread-to-session, the KernelFunction compatibility bridge, DI changes, and the gotchas that bite mid-cutover.

2026-07-06 errors csharp csharp-14

Fix: CS9035 "Required member 'X' must be set in the object initializer" in C#

CS9035 means a member marked required was not assigned. Set it in the object initializer, or add a constructor annotated with [SetsRequiredMembers] that assigns every required member.