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347 posts · Page 14 of 35

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.

2026-07-03 dotnet efcore csharp

How to use named query filters for soft delete and multi-tenancy in EF Core 11

Apply two independent global query filters to the same entity in EF Core 11: a soft-delete filter and a tenant filter, each named so you can disable one without the other via IgnoreQueryFilters.

2026-07-01 csharp dotnet async

How to implement and consume IAsyncDisposable with await using in C#

A complete guide to IAsyncDisposable in C#: when to use await using, how to write DisposeAsync and DisposeAsyncCore correctly, and the stacking and ConfigureAwait gotchas that leak resources.

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.

2026-06-25 csharp dotnet dotnet-11

Why your ASP.NET Core JWT returns 401 even with a valid token

A valid token that still 401s almost always means the bearer handler never ran or ran under the wrong scheme. Check middleware order, the default scheme, the scheme name, and whether the header even reached the handler.