Tag: dotnet-11

.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.

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.

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.

Register more than one implementation of the same interface under a key with AddKeyedSingleton/Scoped/Transient, then resolve them with [FromKeyedServices], GetRequiredKeyedService, or KeyedService.AnyKey. The keyed and non-keyed registries are separate, which is the gotcha that bites most people.

A complete guide to TokenValidationParameters in ASP.NET Core 11: how ValidateIssuer, ValidateAudience, and ValidateLifetime work, what the defaults actually are, why Authority auto-configures the issuer and signing keys, the 5-minute ClockSkew trap, and how to read the IDX error codes when a valid-looking token is rejected.

C# 15 adds the closed modifier in .NET 11 Preview 5, giving class hierarchies compile-time exhaustiveness in switch expressions. Here is how it works and the one gotcha.

A complete guide to CORS for a bearer-token API in ASP.NET Core 11: the correct UseCors ordering relative to authentication, why a bearer token in the Authorization header is not a CORS credential, why AllowAnyHeader works but a manual wildcard does not cover Authorization, and how to keep preflight from failing.

DynamicallyAccessedMembers tells the .NET trimmer and AOT compiler which members of a Type you reach by reflection, so they are kept instead of trimmed away. It turns a silent runtime MissingMethodException into a build-time IL2070 warning. Here is what the attribute does, how the data-flow analysis behind it works, and how to annotate parameters, fields, and generic type parameters correctly.

ValueTask and ValueTask<T> are structs that let an async method return a result without heap-allocating a Task when it completes synchronously. The win is one fewer allocation on hot paths that usually finish without awaiting. The cost is a strict await-once contract. Here is what the type actually is, how it works, and the narrow set of cases where it earns its keep.

A plain-language guide to C# source generators: what they actually do, how the IIncrementalGenerator pipeline works, when they beat reflection or T4, and the cases where you should not reach for one. With runnable examples on .NET 11 and C# 14.