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Tag: dotnet-11

213 posts · Page 15 of 22

2026-05-10 errors csharp dotnet

Fix: Unable to resolve service for type 'X' while attempting to activate 'Y'

ASP.NET Core throws this when a constructor asks for a type that was never registered, was registered on the wrong container, or was added after the host was built. Three concrete fixes cover almost every case.

2026-05-09 errors csharp dotnet

Fix: TaskCanceledException: A task was canceled in HttpClient

HttpClient throws TaskCanceledException for three different reasons: timeout, caller cancellation, or a connection-level abort. Tell them apart with InnerException and CancellationToken.IsCancellationRequested, then fix the right one.

2026-05-08 errors csharp dotnet

Fix: The JSON value could not be converted to System.DateTime

System.Text.Json only accepts ISO 8601 strings for DateTime. Send 2026-05-08T14:00:00Z or register a JsonConverter that parses your format. Empty strings and Unix timestamps both throw.

2026-05-07 errors csharp dotnet

Fix: The instance of entity type cannot be tracked because another instance with the same key value is already being tracked

EF Core 11 throws when two objects share a primary key inside one DbContext. Detach the old one or update it in place. AsNoTracking on the read prevents the collision.

2026-05-07 errors csharp dotnet

Fix: A second operation was started on this context instance before a previous operation completed

EF Core throws when two awaits run in parallel on the same DbContext. Await each call sequentially, or get a new DbContext per concurrent unit of work via IDbContextFactory.

2026-05-06 ai-agents semantic-kernel llm

How to Run a Semantic Kernel Plugin From a BackgroundService

Wire a Microsoft.SemanticKernel 1.75.0 plugin into a hosted BackgroundService on .NET 11 and invoke its KernelFunctions on a PeriodicTimer schedule. Covers DI scopes, [KernelFunction] resolution, prompt-cache-friendly invocation, cancellation, and the lifetime gotchas that bite when you move a plugin off the request path.

2026-05-05 errors csharp dotnet

Fix: System.InvalidOperationException: No connection string named 'DefaultConnection' could be found

If GetConnectionString returns null in .NET 11, your appsettings.json is missing the key, not copied to the build output, or the wrong environment file is being selected. Three checks fix 95% of cases.

2026-05-04 maui dotnet-maui dotnet-11

How to package a .NET MAUI app for the Microsoft Store

End-to-end guide to packaging a .NET MAUI 11 Windows app as an MSIX, bundling x64/x86/ARM64 into a .msixupload, and submitting through Partner Center: identity reservation, Package.appxmanifest, dotnet publish flags, MakeAppx bundling, and the Store-trusted certificate handoff.

2026-05-03 llm ai-agents dotnet

How to Add Tool Calling to a Microsoft.Extensions.AI Chat Client

Wire AIFunctionFactory.Create, ChatOptions.Tools, and ChatClientBuilder.UseFunctionInvocation in Microsoft.Extensions.AI 10.5 so an IChatClient can call your .NET methods automatically. Covers OpenAI and Azure OpenAI providers, the FunctionInvokingChatClient knobs that actually matter (iteration limits, concurrent calls, approval prompts, error handling), and streaming responses with tools.

2026-05-03 maui dotnet-maui dotnet-11

How to implement drag-and-drop in .NET MAUI 11

End-to-end drag-and-drop in .NET MAUI 11: DragGestureRecognizer, DropGestureRecognizer, custom DataPackage payloads, AcceptedOperation, gesture position, and the per-platform PlatformArgs traps on Android, iOS, Mac Catalyst, and Windows.