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2026-10-11 csharp dotnet

How to tail a log file in C# while another process is still writing to it

Open the log with FileShare.ReadWrite | FileShare.Delete, seek to the end, poll for new bytes, decode them with your own UTF-8 Decoder instead of StreamReader, and handle truncation and rotation explicitly. A tested tail -F implementation for .NET 10 and .NET 11.

2026-10-26 dotnet csharp

How to use a different Serilog output template per log level from appsettings.json

outputTemplate is fixed per sink, so per-level formatting needs either an ExpressionTemplate with {#if @l ...} blocks or two Logger sub-loggers with ByIncludingOnly / ByExcluding filters. Both configured purely from appsettings.json, tested on Serilog 4.4, Serilog.Settings.Configuration 10.0.1 and Serilog.Expressions 5.0.

2026-10-04 dotnet dotnet-10

How to detect Windows session lock, unlock, logon and logoff events in a C# app

Use SystemEvents.SessionSwitch in a desktop or console app, override OnSessionChange in a Windows service, or hook WM_WTSSESSION_CHANGE yourself. Covers .NET 10 code for all three, the hidden '.NET System Events' thread, why services see logon but desktop apps do not, out-of-order notifications, and how to query the current lock state with WTSQuerySessionInformation.

2026-11-04 nuget dotnet agent-skills

NuGet Packages Can Now Carry Agent Skills: What Lives in the skills/ Folder

On November 3, 2026 the .NET team showed agent skills shipping inside NuGet packages as skills/<name>/SKILL.md. Here is the layout, how restore exposes it through project.assets.json, the two tools that read it today, and what is still missing.

2026-11-04 csharp dotnet garbage-collection

What happens if you start a thread from a finalizer in .NET?

Starting a thread inside a finalizer works, but the new thread is a normal-priority foreground thread that resurrects the object, outlives GC.WaitForPendingFinalizers, can crash the process, and may touch objects that were already finalized. Blocking on it hangs shutdown. Eight cases reproduced on .NET 10 with real output, plus the safe handoff pattern.

2026-11-04 csharp dotnet async

What is AsyncLocal<T>, and why doesn't a value set inside an awaited method flow back to the caller?

AsyncLocal<T> stores a value in the ExecutionContext, which flows down into awaits, Task.Run and continuations but never back up: every async method restores the caller's context when it returns. Verified on .NET 10: eleven cases with real output, the runtime code that does the restore, and three patterns that do get a value back to the caller.

2026-11-04 mcp ai-agents llm

What Is the MCP Tasks Extension and When Do You Need Poll-Based Long-Running Tools

The MCP Tasks extension (io.modelcontextprotocol/tasks, spec 2026-07-28, SEP-2663) lets a server answer tools/call with a durable task handle instead of a result. The client polls tasks/get, answers mid-flight questions with tasks/update, and can cancel or reconnect. Here is the wire protocol, what changed from the experimental 2025-11-25 version, when a task is worth it, and a working server and client checked against @modelcontextprotocol/ext-tasks 0.2.2.

2026-11-03 blazor aspnetcore dotnet

Syncfusion Blazor Toolkit 2.0.1: 17 MIT Components, No License Key, No Data Grid

On October 29, 2026 Microsoft announced Syncfusion as a Blazor contributor. The headline is Syncfusion.Blazor.Toolkit 2.0.1: 17 MIT-licensed components for net8.0, net9.0 and net10.0, free for commercial use with no license key. Here is what is in it, how to wire it up, and where the commercial line is drawn.

2026-11-03 csharp dotnet attributes

What does [CallerArgumentExpression] capture, and how do I use it in my own guard methods?

[CallerArgumentExpression] makes the C# compiler pass the source text of an argument as a string. Verified on .NET 10 and C# 14: what exactly gets captured (whitespace, comments, parentheses, line breaks), when you get null instead, how to write NotNull, Positive and That guards, and the overload trap that silently disables it.

2026-11-03 claude-code ai-agents anthropic

What Is Claude Tag and How Does It Bring Claude Into Slack

Claude Tag is Anthropic's shared Slack agent: one org-owned identity per channel scope, with channel memory, admin-granted connectors, a GitHub App for draft PRs, and a monthly spend limit. Here is what it is, how setup and pairing work, how it differs from the old Claude in Slack and Claude Code in Slack apps, and the data-retention and billing details to check before you turn it on.

2026-11-03 csharp dotnet native-aot

What is [ModuleInitializer] in C# and when should a library use it?

[ModuleInitializer] makes the C# compiler emit a <Module> static constructor that calls your method once per assembly. When it runs is looser than most people think: on the JIT it can fire before a branch that never executes, under Native AOT it runs eagerly at startup or not at all. Why CA2255 warns libraries off it, the few cases where a library should still use it, and measured behaviour on .NET 10.

2026-11-03 dart flutter pub

What is pubspec_overrides.yaml and when should I use it in a Flutter monorepo?

pubspec_overrides.yaml is a file next to pubspec.yaml that pub reads on top of it, limited to dependency_overrides, resolution and workspace. It replaces the whole dependency_overrides section, applies workspace-wide, and is left out of published archives. What it does, when to use it in a monorepo, and every edge case, verified on Dart 3.12.2.

2026-11-02 microsoft-agent-framework dotnet ai-agents

Agent Framework 1.27: A Redirect Can No Longer Switch Your Declarative Workflow to an Authenticated HttpClient

Microsoft Agent Framework for .NET 1.27.0 makes DefaultHttpRequestHandler throw HttpRequestException when its client-provider callback returns a client for a redirect destination. Here is why that hole existed, what breaks, and how to rewrite the callback.

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