Fix: CS1998 "This async method lacks 'await' operators and will run synchronously" in C#
CS1998 means an async method has no await, so it runs synchronously. Drop the async modifier and return Task.FromResult, or add the await you forgot.
Tag: csharp
300 posts · Page 4 of 30
Live Speech-to-Text in C# with Foundry Local: A 0.67 GB Model and No Cloud Call
The .NET blog shipped a live microphone transcription sample on August 4, 2026 using Foundry Local and nemotron-speech-streaming-en-0.6b. Here is the session API, the PCM backpressure trap, and which NuGet package to pick.
Agent Framework's Copilot Provider Turns the Copilot CLI Into a Plain AIAgent
Microsoft.Agents.AI.GitHub.Copilot 1.16.0 shipped on July 30, 2026. The Copilot CLI runtime now sits behind the ordinary AIAgent abstraction, permissions are deny-by-default, and Squad plugs a whole agent team in as one AIAgent.
How to validate options at startup with IValidateOptions<T> in .NET 11
Implement IValidateOptions<T>, register it in DI, and chain ValidateOnStart so a bad appsettings.json kills the process instead of the first request that touches it. Covers the .NET 11 Validate<TValidator>() overload, async validation through IAsyncValidateOptions<T>, and the three places ValidateOnStart silently does nothing.
How to configure Kestrel to serve HTTP/3 in ASP.NET Core 11
A complete guide to enabling HTTP/3 on Kestrel in ASP.NET Core 11: the HttpProtocols.Http1AndHttp2AndHttp3 endpoint config, MsQuic platform requirements on Windows, Linux, and macOS, why the first request is never HTTP/3, how to verify with HttpClient and middleware, QuicTransportOptions tuning, and the firewall and proxy gotchas that make it silently fall back.
How to replace new Regex(...) with the [GeneratedRegex] source generator in .NET 11
A complete guide to converting new Regex(pattern, RegexOptions.Compiled) into [GeneratedRegex] in .NET 11: the mechanical rewrite, partial methods vs partial properties, measured startup and throughput numbers, the SYSLIB1040-1045 diagnostics, and the two patterns where the generator silently falls back to a cached Regex.
How to run CPU-bound work in a Blazor WebAssembly app with Web Workers in .NET 11
A complete guide to offloading CPU-bound work off the Blazor WebAssembly UI thread in .NET 11: why Task.Run does not help, the new blazorwebworker template, the WebWorkerClient API with cancellation and timeouts, the JSExport marshalling limits, and the second-runtime cost you pay per worker.
IOptions<T> vs IOptionsSnapshot<T> vs IOptionsMonitor<T> in .NET 11
Default to IOptions<T>. Use IOptionsMonitor<T> when a singleton has to see config reloads, and IOptionsSnapshot<T> only when a scoped consumer wants a value that is stable for one request. The deciding axis is the lifetime of the consumer, not the shape of the settings.
Fix: Your startup project doesn't reference Microsoft.EntityFrameworkCore.Design
Add Microsoft.EntityFrameworkCore.Design to the startup project that dotnet ef builds, not the project holding your DbContext, and pass -s in layered solutions.
Fix: Reflection-based serialization has been disabled for this application
This InvalidOperationException means PublishTrimmed or PublishAot flipped JsonSerializerIsReflectionEnabledByDefault to false. Fix it with a source-generated JsonSerializerContext.