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Tag: dotnet-11

269 posts · Page 11 of 27

2026-07-09 dotnet trimming native-aot

What is trim-safe code and how do I write it?

Trim-safe code is code the .NET trimmer can statically prove is reachable, so it survives when unused code is removed from a self-contained app. This is the practical guide: turn on the analyzer, drive every IL2xxx warning to zero, annotate reflection with DynamicallyAccessedMembers, propagate RequiresUnreferencedCode to public APIs, and replace unanalyzable patterns with source generators.

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.

2026-07-06 errors csharp csharp-14

Fix: CS9035 "Required member 'X' must be set in the object initializer" in C#

CS9035 means a member marked required was not assigned. Set it in the object initializer, or add a constructor annotated with [SetsRequiredMembers] that assigns every required member.

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.

2026-07-03 csharp dotnet dotnet-11

How to set up JWT bearer authentication in a minimal API in ASP.NET Core 11

A complete, working setup for JWT bearer authentication in an ASP.NET Core 11 minimal API: install the package, wire up AddAuthentication().AddJwtBearer(), issue a token, protect endpoints with RequireAuthorization, add role and claim policies, and test the whole thing with dotnet user-jwts.

2026-07-01 csharp dotnet dotnet-11

How to propagate a CancellationToken through async methods in .NET 11

Thread a CancellationToken cleanly through every layer of an async call chain in .NET 11: last-parameter convention, default values, linked tokens, ASP.NET Core RequestAborted, and the CA2016 analyzer that catches the ones you drop.

2026-07-01 csharp dotnet dotnet-11

How to time out an async operation with CancellationTokenSource.CancelAfter in C#

Use CancellationTokenSource.CancelAfter to enforce an async deadline in .NET 11: constructor vs CancelAfter, linked tokens for composing timeouts with caller tokens, exception disambiguation, Task.WaitAsync, TryReset for pooling, and testable timeouts with TimeProvider.

2026-06-26 errors csharp dotnet

Fix: FOREIGN KEY constraint failed when deleting an entity in EF Core 11

EF Core throws FOREIGN KEY constraint failed because the parent still has dependents the database refuses to orphan. Load the children, make the relationship optional, or configure OnDelete.

2026-06-26 errors csharp dotnet

Fix: No service for type 'Microsoft.EntityFrameworkCore.DbContextOptions' has been registered

EF Core throws this when AddDbContext never ran, ran after Build, or your context's constructor takes the wrong DbContextOptions. Register before Build and use DbContextOptions<YourContext>.

2026-06-25 errors csharp dotnet

Fix: 405 Method Not Allowed instead of 401 with JWT bearer in ASP.NET Core

A protected endpoint returning 405 instead of 401 almost always means routing rejected the HTTP verb before auth ran, or a cookie scheme stole the challenge. Here is how to tell which.