Fix: The antiforgery token could not be decrypted in ASP.NET Core
The error means Data Protection lost the key that signed the token. Persist keys to a shared, durable store and call SetApplicationName so every instance reads the same key ring.
Tag: aspnetcore
89 posts · Page 7 of 9
Blazor static SSR forms get client-side validation in .NET 11 Preview 5
Static server-rendered Blazor forms could only validate after a full POST round-trip. .NET 11 Preview 5 renders validation metadata so the Blazor JS enforces DataAnnotations rules in the browser, no circuit required.
Fix: its render mode is not supported by the parent component's render mode (Blazor)
You put @rendermode on a child whose parent is already interactive. A subtree has exactly one render mode. Remove the child directive or move it to the boundary.
How to persist state across the Blazor static-to-interactive render boundary in .NET 11
A prerendered Blazor component runs its initialization twice and loses state at the interactive handoff. Fix it with the [PersistentState] attribute or the PersistentComponentState service in .NET 11.
How to expose OpenAPI without Swashbuckle in ASP.NET Core 11
Swashbuckle is gone from the ASP.NET Core templates. Here is how to generate and serve an OpenAPI document in .NET 11 with the built-in Microsoft.AspNetCore.OpenApi package: AddOpenApi, MapOpenApi, transformers, multiple documents, build-time generation, and a UI on top.
How to organize minimal API endpoints with MapGroup in ASP.NET Core 11
A complete guide to structuring minimal APIs in ASP.NET Core 11 with MapGroup: per-resource endpoint modules as extension methods, nested groups, shared filters and auth, route-parameter prefixes, OpenAPI tags, and the filter-ordering rules that surprise people.
How to use HybridCache in ASP.NET Core 11 with Redis as the L2 cache
Wire HybridCache to a Redis L2 in ASP.NET Core 11: register the service, add the StackExchange Redis distributed cache, and let GetOrCreateAsync give you a two-tier cache with built-in stampede protection and tag invalidation.
How to validate request bodies in minimal APIs without controllers in ASP.NET Core 11
ASP.NET Core 11 has built-in validation for minimal APIs: call AddValidation, annotate your request record with DataAnnotations, and a source generator validates the bound model and returns 400 ProblemDetails before your handler runs. No controllers, no FluentValidation, no manual checks.
Migrate a Blazor Server app to Blazor United (Blazor Web App) in .NET 11
A step-by-step checklist to move a standalone Blazor Server app to the unified Blazor Web App template on .NET 11, keeping every page on InteractiveServer with zero behaviour change.
BackgroundService vs IHostedService vs Hangfire for background jobs in .NET 11
Pick BackgroundService for in-process loops, raw IHostedService when you need fine lifecycle control, and Hangfire when jobs must survive a restart. A decision matrix with code and the one gotcha that picks for you.