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Tag: dotnet-11

213 posts · Page 6 of 22

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.

2026-06-25 errors csharp dotnet

Fix: The seed entity for entity type 'X' cannot be added because a non-zero value is required for property 'Id'

HasData seeds an entity with a store-generated key but no explicit value. Give every seed row a stable non-zero Id, or switch to UseSeeding for generated keys.

2026-06-24 how-to csharp csharp-14

How to declare extension properties in C# 14

Extension properties land in C# 14 through the new extension block. Declare get-only, settable, static, and generic extension properties, why auto-properties are rejected, and how the compiler lowers them to get_/set_ accessors.

2026-06-23 dotnet dotnet-11

.NET 11 Preview 5 lets file-based apps reference each other with `#:ref`

.NET 11 Preview 5 adds the #:ref directive so a dotnet run script can reference another file-based app as a library, with transitive references and no project file.

2026-06-23 how-to ef-core ef-core-11

How to do keyset (cursor) pagination in EF Core 11

Replace Skip/Take with a WHERE clause that seeks past the last row you saw. Order by a fully unique key, carry the last row's values as a cursor, and EF Core 11 turns the next page into an index seek instead of an OFFSET scan.

2026-06-23 how-to ef-core ef-core-11

How to map and query JSON columns in EF Core 11

Map a nested type to a single JSON column with ComplexProperty(...).ToJson(), let EF Core 11 store it in the native SQL Server 2025 json type, then query into it with LINQ that translates to JSON_VALUE, JSON_CONTAINS, and JSON_PATH_EXISTS.