Tag: dotnet

Attach a JsonTypeInfo modifier to a source-generated JsonSerializerContext in .NET 11: why new MyContext(options) silently drops it, the WithAddedModifier setup that works, the fast path you give up (measured), and the naming-policy trap that makes modifiers no-op.

A complete guide to file-based C# apps: running a single .cs file with dotnet run, the #:package, #:sdk, #:property, #:project and #:include directives, multi-file scripts with #:ref, argument and stdin handling, the build cache, native AOT publishing, packaging as a dotnet tool, and dotnet project convert when the script outgrows itself.

Replace UseSwaggerUI with MapScalarApiReference in ASP.NET Core 11: routing, multiple documents, pre-filled auth, production gating, offline assets, and the Scalar-only OpenAPI extensions that mark endpoints stable or hidden.

Aspire 13.4.6 wins the .NET inner loop because it runs your projects as host processes you can debug, while Docker Compose wins when the compose file is also your CI and deployment contract. Measured startup and edit-to-running timings on both, the configuration each one injects for you, and the six gotchas that decide it.

The .NET blog's August 6, 2026 post on MTP reporting surfaces a batch of extensions that went stable in Microsoft.Testing.Platform 2.3.0: GitHub Actions annotations, crash-resilient TRX streaming, and Azure DevOps flaky history.

Replace a hand-rolled classifier-plus-switch router with AgentWorkflowBuilder.CreateHandoffBuilderWith in Microsoft.Agents.AI.Workflows 1.17.0. What breaks, the six migration steps, and the gotchas around agent Ids, descriptions, and context broadcast.

They are not alternatives. WebApplicationFactory boots your app, Testcontainers boots your dependencies. Measured on .NET SDK 10.0.201: a container fixture costs 1.7 s per class against 10 ms for SQLite, and a HasMaxLength(16) violation that Postgres rejects with 22001 is silently accepted by SQLite.

Pick xUnit v3 for greenfield .NET projects, NUnit 4.6 if you live in its constraint model, MSTest 4 if you already ship it. A measured comparison on .NET SDK 10.0.201 covering parallelism defaults, test class lifecycle, assertion failure output, and the Microsoft.Testing.Platform version conflict that breaks the NUnit runner.

For internal service-to-service calls in .NET 11, default to gRPC when you own both ends of the contract and the call is point-to-point. Use REST with JSON when anything you do not control has to call the service. SignalR is not an RPC transport between services: reach for it only when one producer has to fan a message out to many long-lived consumers.

Use declarative YAML when the graph is a sequential routing decision that non-developers change often. Use code-first WorkflowBuilder the moment you need parallelism, custom executors, or a non-Foundry agent. Here is the decision, the action catalog limits, and the code both ways.