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Tag: minimal-apis

14 posts · Page 1 of 2

2026-09-13 aspnetcore minimal-apis dotnet-11

How to bind a complex query-string object with [AsParameters] in a minimal API in ASP.NET Core 11

Put [AsParameters] on a class or record to bind a whole query-string filter in an ASP.NET Core 11 minimal API. Covers defaults, arrays, enums, nested objects, validation, OpenAPI, and a Native AOT generator bug with positional records.

2026-08-20 errors dotnet dotnet-11

Fix: [FromForm] Dictionary<string, string> is always null in a minimal API

A [FromForm] Dictionary in a minimal API binds with an empty prefix: the form keys must be [key], not metadata[key]. Wrap it in a class to keep readable names.

2026-08-16 csharp dotnet dotnet-11

How to download a file from a Blazor component without JavaScript interop

Skip the downloadFileFromStream JS module entirely. Render an anchor with the download attribute pointing at a minimal API endpoint that returns TypedResults.File, or POST a plain HTML form with an AntiforgeryToken. Covers why the download attribute is what stops Blazor's enhanced navigation from swallowing the click, why data-enhance silently discards the file, and the cookie-vs-bearer auth trap.

2026-07-23 comparison csharp dotnet

Typed results (Results<>) vs IResult vs IActionResult in ASP.NET Core 11

In ASP.NET Core 11, return Results<T1, TN> with TypedResults for minimal APIs and ActionResult<T> for controllers. Treat bare IResult and bare IActionResult as escape hatches: they compile for any response but describe nothing to OpenAPI, so you pay for them in hand-written ProducesResponseType attributes.

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.

2026-07-14 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.

2026-07-09 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.

2026-07-03 csharp dotnet dotnet-11

How to customize minimal API validation error responses with IProblemDetailsService in ASP.NET Core 11

Call AddProblemDetails with a CustomizeProblemDetails callback to reshape the 400 that built-in minimal API validation returns in ASP.NET Core 11: add a traceId, rewrite the title, switch 400 to 422, or take full control with a custom IProblemDetailsWriter.

2026-06-15 comparison aspnetcore dotnet-11

Minimal API validation vs FluentValidation in ASP.NET Core 11: which should you pick?

Use the built-in source-generated validation for synchronous, attribute-expressible rules in ASP.NET Core 11; reach for FluentValidation when you need async rules, complex cross-field logic, or validation kept out of your domain models.