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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.

2026-10-31 comparison ai-agents claude-code

Fail-Closed vs Fail-Open Hooks for Coding Agent Guardrails: What Claude Code, Cursor, Copilot, Codex and Gemini CLI Actually Do

A guard hook that crashes or times out lets the dangerous command through in most coding agents. Fail closed for pre-action guards, fail open for everything else, and make the script fail closed by itself because Copilot, Codex and Gemini CLI treat a timeout as allow. Compared on Claude Code 2.1.295+, Cursor hooks, Copilot CLI 1.0.105, Codex and Gemini CLI, with a portable guard script.

2026-10-31 grpc aspnetcore dotnet

grpc-dotnet 2.85 Enforces MaxReceiveMessageSize After Decompression, Not Just Before

Grpc.AspNetCore and Grpc.Net.Client 2.85.0 now apply MaxReceiveMessageSize to the decompressed size of gzip and deflate messages. A 260 KB request that inflates to 256 MiB is rejected with ResourceExhausted, but legitimate large compressed payloads can start failing too.

2026-10-31 comparison csharp dotnet

yield return iterator vs returning a List<T>: what an IEnumerable method actually costs in C#

A yield return method costs one 40-byte state machine object per call no matter how many items it produces; a List<T> costs the whole backing array up front. Measured on .NET 10.0.10: iterator wins on memory and early exit, List<T> wins when the caller enumerates more than once, needs Count, or calls ToList().

2026-10-30 comparison dotnet dotnet-10

FileSystemInfo.LastWriteTime setter vs File.SetLastWriteTime in .NET

Both end in the same OS call, so the timestamp written is identical. The differences are around it: which cache gets invalidated, whether directories work on Windows, how a non-UTC DateTime is converted, and whether you can target an open handle. Use File.SetLastWriteTimeUtc, by handle when the file is open. Verified on .NET 10.0.10.

2026-10-30 marten postgresql dotnet

Marten 9.55 Fixes the Turkish I in Document Table Names: Rename Before You Upgrade

Marten 9.55.0 lowers document aliases, DDL template keys and flat-table upsert function names with the invariant culture. Apps running under tr-TR or az-AZ that store documents in tables like mt_doc_ınvoice must rename them first, or their data appears to vanish.

2026-10-30 llm claude-code ai-agents

Migrate a Coding Agent from Claude Sonnet 4.6 and Opus 4.7 to the 5.5 Family: Model IDs, Effort, and Cost

Moving an agent from claude-sonnet-4-6 or claude-opus-4-7 to claude-sonnet-5-5 or claude-opus-5-5 is not just a model ID swap. Thinking is always on, thinking-off and forced tool_choice now return 400, the effort defaults moved, Sonnet counts about 30% more tokens, and Claude Code ignores your old effortLevel on Opus 5.5. Here is the full checklist with before/after code.

2026-10-30 comparison csharp dotnet

ref T loop vs Span<T> indexing in C#: why the span version is as fast or faster in .NET 10

On .NET 10 a plain for loop over span[i] bounded by span.Length compiles to a bounds-check-free, strength-reduced, down-counting loop. A hand-written Unsafe.Add(ref r, i) loop with an int index keeps a sign extension and an up-counting compare, and measured 2-5% slower. Benchmarks and JIT disassembly for arm64 and x64 on .NET 10.0.10.

2026-10-30 comparison flutter dart

shared_preferences vs a JSON File in path_provider for Persisting Settings in Flutter

Use shared_preferences (SharedPreferencesWithCache) for a handful of flat flags and a JSON file in getApplicationSupportDirectory for a structured settings object. Covers the atomic-write pattern, the concurrent-save race, the Documents-folder trap on Windows and Linux, web support, and measured write costs on Flutter 3.44.8.

2026-10-29 errors nuget azure-devops

Fix: Azure DevOps NuGet restore fails with "Unable to find version 'x.y.z' of package" from an internal feed

The version exists, but the pipeline cannot see it. Check the build identity's feed role, the feed view in the URL, which nuget.config the task uses, package source mapping, and the 30-minute HTTP cache.

2026-10-29 errors flutter flutter-3-47

Fix: flutter upgrade says "Your flutter checkout has local changes that would be erased by upgrading"

flutter upgrade aborts if git status in the SDK folder prints anything. Inspect it, restore pubspec.lock or git stash -u, and use --force only as a last resort.

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