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Tag: dotnet-11

313 posts · Page 9 of 32

2026-08-09 ef-core ef-core-11 migrations

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.

2026-08-09 csharp dotnet dotnet-11

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.

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.

2026-08-06 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 csharp dotnet

Fix: AggregateException "One or more errors occurred" when awaiting Task.WhenAll in C#

await Task.WhenAll rethrows only one of the failures. Keep the WhenAll task in a variable and read its Exception.InnerExceptions to see every error instead of one.

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 ef-core ef-core-11 concurrency

How to implement optimistic concurrency with a rowversion token in EF Core 11

Add a rowversion concurrency token in EF Core 11: the [Timestamp] and IsRowVersion setup, the SQL EF actually emits, catching DbUpdateConcurrencyException, store-wins vs client-wins vs merge, disconnected APIs with ETags, and the five traps that silently disable the whole thing.

2026-08-03 ef-core ef-core-11 value-converters

How to store an enum as a string in EF Core 11 with a value converter

Store C# enums as readable strings instead of ints in EF Core 11: HasConversion, bulk configuration for every enum, the nvarchar(max) trap, the ordering gotcha, and how to migrate an existing int column.

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.