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.
Tag: dotnet-11
268 posts · Page 4 of 27
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.
How to call a stored procedure and map its results in EF Core 11
Use FromSql on a DbSet when the procedure returns full entity rows, Database.SqlQuery<T> when it returns a projection, and ExecuteSql when it returns nothing. Never chain a LINQ operator onto an EXEC, and never read an output parameter before the reader is disposed.
How to customize source-generated System.Text.Json serialization with a type-info resolver modifier
Attach a JsonTypeInfo modifier to a source-generated JsonSerializerContext in .NET 11: why new MyContext(options) silently drops it, the WithAddedModifier setup that works, the fast path you give up (measured), and the naming-policy trap that makes modifiers no-op.
How to override the default resilience handler that Aspire registers
Aspire's AddServiceDefaults applies a standard resilience handler to every HttpClient. Calling AddStandardResilienceHandler again stacks a second one instead of replacing it. Here are the three real override paths, the -standard options name nobody documents, and the infinite timeout you inherit if you just remove it.
How to rename a table in an EF Core 11 migration without losing data
EF Core scaffolds RenameTable when you change the table name, but DropTable plus CreateTable when you rename the entity class. Here is how to tell the two apart, the ToTable trick that makes a class rename free, and the column-rename bug that silently swaps your data.
How to run a file-based C# app with `dotnet run app.cs` in .NET 11
A complete guide to file-based C# apps: running a single .cs file with dotnet run, the #:package, #:sdk, #:property, #:project and #:include directives, multi-file scripts with #:ref, argument and stdin handling, the build cache, native AOT publishing, packaging as a dotnet tool, and dotnet project convert when the script outgrows itself.
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.
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].
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.