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ASP.NET Core

122 posts · Page 5 of 13

2026-08-13 dotnet-11 aspnetcore blazor

Blazor Server Circuits Now Pause Themselves When the Tab Goes Idle

.NET 11 Preview 7 adds an opt-in package that pauses interactive Server circuits when the browser tab is hidden, freeing memory and SignalR connections held by users who are not actually there.

2026-08-13 errors blazor aspnetcore

Fix: 404 Not Found for blazor.server.js after installing a new .NET SDK

blazor.server.js 404s on .NET 10 because the script stopped being an embedded resource. Add RequiresAspNetWebAssets to the host project, or make sure it has a .razor file.

2026-08-12 errors aspnetcore dotnet

Fix: The 'interceptors' feature is not enabled in this namespace

CS9137 comes from the Microsoft.AspNetCore.OpenApi source generator. Add InterceptorsNamespaces to every project that calls AddOpenApi, not just the one holding the PackageReference.

2026-08-11 errors aspnetcore dotnet

Fix: The type or namespace name 'OpenApiReference' could not be found

OpenApiReference was deleted in Microsoft.OpenApi 2.0. Changing the using to Microsoft.OpenApi is not enough: replace each usage with a typed reference such as OpenApiSchemaReference.

2026-08-09 csharp dotnet dotnet-11

How to serve OpenAPI documentation with Scalar instead of Swagger UI in ASP.NET Core 11

Replace UseSwaggerUI with MapScalarApiReference in ASP.NET Core 11: routing, multiple documents, pre-filled auth, production gating, offline assets, and the Scalar-only OpenAPI extensions that mark endpoints stable or hidden.

2026-08-07 comparison dotnet aspnetcore

WebApplicationFactory vs Testcontainers for ASP.NET Core integration tests

Choose an ASP.NET Core integration-test setup by what it must prove: HTTP routing, production database behavior, or the published application image.

2026-08-06 errors blazor aspnetcore

Fix: Attempting to reconnect to the server after a Blazor Server circuit disconnects

The reconnect modal means the SignalR circuit dropped, not that your app crashed. Decide whether the retry ended in failed or rejected, then fix sticky sessions, the 3-minute retention window, the 32 KB message limit, or persist circuit state with [PersistentState].

2026-08-06 comparison dotnet dotnet-11

gRPC vs REST vs SignalR for service-to-service calls in .NET 11

For internal service-to-service calls in .NET 11, default to gRPC when you own both ends of the contract and the call is point-to-point. Use REST with JSON when anything you do not control has to call the service. SignalR is not an RPC transport between services: reach for it only when one producer has to fan a message out to many long-lived consumers.

2026-08-05 errors dotnet dotnet-11

Fix: HTTP Error 500.30 - ASP.NET Core app failed to start after deploying to IIS

500.30 means your app threw during startup inside w3wp.exe. The real exception is already in the Windows Application event log under IIS AspNetCore Module V2. Read that first, then rank the fix: missing shared framework, x86/x64 app pool mismatch, missing config, or app pool permissions.

2026-08-03 csharp dotnet dotnet-11

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.