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dotnet-11

328 posts · Page 7 of 33

2026-09-01 comparison csharp csharp-14

Returning a Task directly vs async/await passthrough in a C# repository method: which should you use?

Eliding async/await in a repository passthrough saves about 6 ns and 72 bytes, and costs you a stack frame, try/catch semantics, and safe disposal. Keep return await unless the method is a pure passthrough on a measured hot path.

2026-08-30 errors ef-core ef-core-11

Fix: 23505: duplicate key value violates unique constraint on a concurrent EF Core insert

The check-then-insert in your handler is not atomic. Catch PostgresException with SqlState 23505, or collapse the whole thing into one INSERT ... ON CONFLICT statement. EnableRetryOnFailure will not help.

2026-08-30 errors ef-core ef-core-11

Fix: CREATE DATABASE permission denied in database 'master' when running dotnet ef database update

EF Core's Migrate() always checks whether the database exists and creates it if not, from a hardcoded master connection. Grant CREATE ANY DATABASE, fix the login's access to the existing database, or ship an idempotent SQL script instead.

2026-08-29 errors maui dotnet

Fix: Doesn't support required ABI when installing a .NET MAUI Android app

The APK has no native library for the device's CPU. Since .NET 9 the default Android RuntimeIdentifiers are 64-bit only, so the fix is to set RuntimeIdentifiers explicitly. Covers ADB0020, XA0036, NETSDK1083, the ABI to RID mapping, the Play Console wording, and why the four-RID snippet everyone copies breaks on .NET 11.

2026-08-29 errors dotnet docker

Fix: failed to resolve source metadata for mcr.microsoft.com/dotnet/aspnet

BuildKit cannot read the manifest for your base image. Check the tag exists, repair the Docker credential helper, open both MCR endpoints, then pre-pull for offline builds.

2026-08-28 aspire dotnet dotnet-11

Aspire 13.5 Puts a Real Terminal Inside the Dashboard

WithTerminal() gives a resource an interactive PTY session you can type into from the dashboard or attach to from your own shell. It is experimental, it detaches the debugger, and the Shell option you may have written against is gone.

2026-08-20 aspnetcore dotnet error-handling

ASP.NET Core Stops Turning 413 Into 500 in UseExceptionHandler

A PR merged into dotnet/aspnetcore main on August 19, 2026 makes ExceptionHandlerMiddleware honour BadHttpRequestException.StatusCode instead of overwriting it with 500.

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.

2026-08-19 errors swashbuckle openapi

Fix: cannot target OpenAPI 3.0 after upgrading Swashbuckle.AspNetCore to v9

Swashbuckle 8 and later emit openapi 3.0.4, not 3.0.1, and there is no OpenApiSpecVersion for a patch version. Why it changed, and four ways to pin the string your tooling expects.

2026-08-19 errors openapi swagger

Fix: Swagger UI shows Unable to render this definition after upgrading to .NET 11

ASP.NET Core 11 emits openapi 3.2.0 by default and Swagger UI below 10.1.5 rejects it. Upgrade Swashbuckle.AspNetCore.SwaggerUI, or pin OpenApiVersion back to OpenApi3_1.