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Tag: dotnet-11

213 posts · Page 3 of 22

2026-07-20 aspnetcore dotnet-11 validation

Async validation lands in Minimal APIs with .NET 11 Preview 6

Preview 6 adds AsyncValidationAttribute and IAsyncValidatableObject so DataAnnotations rules can hit the database before your endpoint runs, without blocking a thread.

2026-07-20 errors csharp csharp-14

Fix: CS8618 "Non-nullable property must contain a non-null value when exiting constructor" in C#

CS8618 means a non-nullable field or property was not initialized by the time the constructor finished. Set it in the constructor, give it a default, mark it required, or make it nullable.

2026-07-20 csharp dotnet dotnet-11

Fix: deadlock when calling .Result or .Wait() on an async method in C#

Blocking on an async Task with .Result or .Wait() deadlocks when a SynchronizationContext is present. Here is why it hangs and how to fix it in .NET 11 and C# 14.

2026-07-19 csharp dotnet dotnet-11

How to add a health check endpoint to a minimal API in ASP.NET Core 11

A complete, working guide to health checks in an ASP.NET Core 11 minimal API: AddHealthChecks and MapHealthChecks, custom IHealthCheck classes returning Healthy/Degraded/Unhealthy, the AddDbContextCheck EF Core probe, tag-based liveness and readiness endpoints for Kubernetes, a JSON ResponseWriter, ResultStatusCodes, securing the endpoint with RequireAuthorization and RequireHost, and pushing results with IHealthCheckPublisher.

2026-07-19 csharp dotnet dotnet-11

How to add an endpoint filter to a minimal API in ASP.NET Core 11

A complete, working guide to endpoint filters in an ASP.NET Core 11 minimal API: AddEndpointFilter with an inline delegate, IEndpointFilter classes with DI, GetArgument and the Arguments list, short-circuiting with Results.Problem, FIFO/FILO ordering across multiple filters, group-level filters on MapGroup, and AddEndpointFilterFactory for signature-aware filters.

2026-07-19 dotnet-11 maui coreclr

MAUI Mobile Is CoreCLR Only in .NET 11 Preview 6: The Mono Escape Hatch Is Gone

.NET 11 Preview 6 removes the separate Mono path for MAUI on Android, iOS, and Mac Catalyst. CoreCLR is now the only mobile runtime, the UseMonoRuntime escape hatch is closed, and GA is set for November 2026.

2026-07-18 dotnet-11 csharp csharp-15

C# 15 Extension Indexers Round Out Extension Members in .NET 11 Preview 6

Extension indexers landed in .NET 11 Preview 6, letting you add this[...] access to types you do not own. They complete the extension members story that started with methods and properties in C# 14.

2026-07-17 aspnetcore dotnet-11 security

ASP.NET Core 11 Preview 6 turns on automatic CSRF protection

Preview 6 rejects unsafe cross-origin browser requests by default, reading the Sec-Fetch-Site header instead of an antiforgery token. Here is what it blocks and how to opt out.

2026-07-17 errors dotnet dotnet-11

Fix: "413 Request Entity Too Large" when uploading a file to an ASP.NET Core endpoint

Kestrel caps request bodies at 30,000,000 bytes by default and returns 413 when you exceed it. Raise MaxRequestBodySize globally, per endpoint, or in web.config behind IIS.

2026-07-17 errors csharp dotnet

Fix: System.InvalidOperationException: Headers are read-only, response has already started

You set a header, status code, or content type after the body was already flushed. Set all headers before the first write, or guard with HttpResponse.HasStarted and OnStarting.