Start Debugging

Tag: aspnetcore

80 posts · Page 4 of 8

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.

2026-07-14 csharp dotnet dotnet-11

How to add response compression to an ASP.NET Core 11 API

A complete guide to response compression in ASP.NET Core 11: AddResponseCompression and UseResponseCompression, the new built-in Zstandard provider alongside Brotli and Gzip, compression levels, EnableForHttps and the CRIME/BREACH risk, custom MIME types, middleware ordering, and when to let the reverse proxy do it instead.

2026-07-14 csharp dotnet dotnet-11

How to return a typed Results<T1, T2> union from a minimal API endpoint in ASP.NET Core 11

Declare the handler's return type as Results<Ok<T>, NotFound> and return TypedResults.Ok / TypedResults.NotFound: the union gives compile-time checking that the handler only returns what it declares, and it self-describes to OpenAPI so you never write .Produces by hand. Covers async handlers, the six-type limit, and testing in ASP.NET Core 11.

2026-07-12 csharp dotnet dotnet-11

How to add output caching to a minimal API in ASP.NET Core 11

A complete, working guide to output caching in an ASP.NET Core 11 minimal API: AddOutputCache and UseOutputCache, CacheOutput on endpoints and MapGroup, named and base policies, Expire, VaryByQuery and VaryByHeader, tag-based eviction with EvictByTagAsync, cache stampede protection, ETag revalidation, and a Redis backing store.

2026-07-12 csharp dotnet dotnet-11

How to customize the OpenAPI document with AddOperationTransformer and AddSchemaTransformer in ASP.NET Core 11

A deep dive into the built-in OpenAPI transformer pipeline in .NET 11: operation vs schema transformers, the context objects, execution order, DI-activated transformers, and recipes for headers, responses, examples, and per-property tweaks.

2026-07-10 dotnet aspnetcore csharp

What is the IHostedService contract and when do I use it?

IHostedService is the two-method interface (StartAsync/StopAsync) the .NET generic host calls on startup and graceful shutdown. Here is exactly what the contract promises, when to implement it directly, and the .NET 10 and 11 behavior changes that catch people out.

2026-07-09 migration aspnetcore dotnet-11

Migrate a minimal API from manual validation checks to built-in validation in ASP.NET Core 11

A step-by-step migration guide for replacing hand-rolled if-checks in ASP.NET Core 11 minimal API handlers with the built-in source-generated DataAnnotations validator: what breaks, which manual rules do and do not port, and how to verify the 400 ProblemDetails contract stays identical.

2026-07-06 errors dotnet dotnet-11

Fix: "415 Unsupported Media Type" from a minimal API endpoint in ASP.NET Core 11

A minimal API returns 415 when the request Content-Type does not match what the endpoint binds. Send Content-Type: application/json for a body-bound type, or use [FromForm] for form and file uploads.