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Tag: dotnet

173 posts · Page 3 of 18

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 dotnet webassembly performance

Copilot Studio's .NET 10 WebAssembly upgrade: 20% cold path, 5% warm

Microsoft moved Copilot Studio's WASM engine from .NET 8 to .NET 10. The dual JIT/AOT package, fingerprinting, and WasmStripILAfterAOT explain the numbers.

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 dotnet ai-agents agent-framework

Microsoft Agent Framework workflows now survive process restarts via the Durable Task stack

Wrap an Agent Framework Workflow in Microsoft.Agents.AI.DurableTask and each executor step is checkpointed. Crash, redeploy, restart - the run continues where it stopped.

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.

2026-05-07 maui xamarin xamarin-forms

Migrate a high-performance Xamarin.Forms ListView to MAUI CollectionView

Step-by-step migration from Xamarin.Forms 5.0 ListView to .NET MAUI 11 CollectionView for apps that already squeezed performance out of ListView. Covers cell recycling, virtualization, grouping, pull-to-refresh, context actions, selection, ItemsLayout, EmptyView, and the gotchas that bite real apps.

2026-05-06 dotnet ai-agents agent-framework

Microsoft Agent Framework gates risky tool calls behind FunctionApprovalRequestContent

Wrap an AIFunction in ApprovalRequiredAIFunction and the agent stops mid-run to ask permission. Here is how the request and response flow works in C#.

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.