Gerald Versluis

@jfversluis.dev

1963 Followers 163 Following

Engineer @microsoft.com (.NET) | content creator | speaker | gamer | .NET MAUI, Blazor, C# | posts & opinions on personal title | He/Him | Talk about what you love, not what you don't. 📍 Maastricht, NL 🎥 YouTube.com/@jfversluis 🔌 jfversluis.dev

Terminal screenshot in Windows PowerShell showing the command copilot --excluded-tools='web_fetch,web_search' at a C source prompt, demonstrating how to start Copilot CLI with web fetch and web search tools excluded.

Desktop screenshot of GitHub Copilot CLI showing the slash command /remote with options to enable or disable remote control, alongside a code diff and session details.

Screenshot of a GitHub Copilot chat showing a PR status update: CI passed on the previous commit, one unresolved review thread remains, and a new CI run is pending.

Graphic titled Copilot session sizing. It compares vague Copilot tasks like make the app better, clean up the codebase, fix performance, and modernize everything with PR-sized tasks like fix this failing test, add this validation rule, update this API call, and include matching tests. Footer says treat each session like a focused branch.

Graphic titled GitHub Actions token permissions. It compares overly broad GITHUB_TOKEN permissions such as write-all with a better default of workflow contents read and write access only for the release job, summarized as start read-only and add writes deliberately.

Graphic titled Central Package Management. It compares package versions scattered across project files before, with a Directory.Packages.props file after, summarizing that one file owns package versions and there is less dependency archaeology.

Cheat sheet graphic titled HttpClient lifetime. It says not to create and dispose HttpClient for every request, warns against connection churn, port pressure, and stale DNS surprises, and recommends either a long-lived HttpClient with PooledConnectionLifetime or IHttpClientFactory named or typed clients.

Checklist graphic titled .NET MAUI release check with six items: cold start on a real device, light/dark switch while running, deep link with real parameters, network off/on, rotate resume background, and fresh install plus upgrade install.

Code-card graphic titled “Stop manual theme checks” comparing manual .NET MAUI theme checks in C# with an AppThemeBinding XAML style named CardStyle that picks light and dark resources automatically and updates when the system theme changes.

Code-card graphic titled “Your queue has no brakes” showing an unbounded List-based queue labeled “no brakes” compared with a bounded Channel<T> example labeled “backpressure”, emphasizing that bounded channels make producer and consumer pressure explicit.

Screenshot of the NuGet.org account menu showing a Trusted Publishing option and an API Keys option marked with a “Not recommended” label.

Code-card graphic titled “Stop hand-rolling timer loops”. It compares a background loop using Task.Delay with a version using PeriodicTimer and WaitForNextTickAsync. The card notes that PeriodicTimer should have one consumer at a time, should be disposed to stop, and should use the cancellation token.

Gerald Versluis holding a physical copy of his book Getting Started with Visual Studio 2026 by Apress, with several additional copies stacked on a table in front of him.

Code-card graphic titled “Freeze read-only lookups”. It compares a static readonly mutable Dictionary loaded by LoadRates with a FrozenDictionary created using ToFrozenDictionary and StringComparer.OrdinalIgnoreCase. The card notes that frozen dictionaries are best when you build once, keep the lookup around, and read many times, and not for dictionaries you keep changing.

Code-card graphic titled “Responsive layouts in .NET MAUI”. It shows a narrow preview with vertically stacked cards and a wide window preview with horizontal cards, alongside XAML using VisualStateManager, VisualStateGroupList, and AdaptiveTrigger MinWindowWidth 800 to switch a StackLayout from vertical to horizontal orientation.

Code-card graphic titled “Delete the timeout helper”. It compares a longer Task.WhenAny plus Task.Delay timeout helper with a shorter Task.WaitAsync example, and notes that CancellationToken should be passed to the underlying operation to stop the work too.

Photo of a hand holding a physical MAUI Day Kraków 2026 badge in front of a blurred dragon statue outdoors.

Circular MAUI Day badge for Köln 2026, showing the Cologne Cathedral and a bridge over water inside a blue and pink badge design.

Code screenshot-style card showing PaymentOptions with Required, Url, and Range validation attributes, and Program.cs binding options with BindConfiguration, ValidateDataAnnotations, and ValidateOnStart so invalid configuration fails at startup.

A PC tower standing on a table and in front of it a new ASRock Intel Arc B580 Challenger

Code screenshot-style card showing TimeProvider injected into app code and FakeTimeProvider used in a unit test to advance time by 15 days without waiting.

Terminal-style screenshot showing a structured GitHub Copilot CLI prompt for fixing a flaky login test, with sections for goal, context, constraints, validation, and report back.

Code screenshot-style card showing .NET MAUI HandlerChanging used to detach an Android native button Click event from the old native view.

Gerald holding up the book AI-Enabled Apps with .NET MAUI by Codrina Merigo, published by Apress, with a surprised expression

XBOX showing that 007 First Light being installed

Screenshot of VS Code Agents window showing multiple coding sessions across different repositories, with a completed session displaying a summary of changes and file diffs. Red arrow highlights the Open in Agents button in the title bar.

Animated GIF showing dotnet watch hot reload working on an Android device, updating the UI in real-time after a code change

Gerald pretending to be sick in front of the TV where Forza Horizon 6 can be seen on XBOX

Partial screenshot of the GitHub Copilot desktop app. It show's a PR that was created and a button that says Merge when ready. The button is expanded showing an option: Enable agent merge. Agent handles CI, comments, and merge.

Instructions for applying a screen protector that says: scan QR to remove bubbles.

A screen showing my purchase of the 007 First Light game on Xbox was successful

VS Code Copilot model picker showing Auto selected with 10% discount, alongside Claude Opus 4.7, Sonnet 4.6, and GPT-5.4

.NET MAUI MapClustering sample app showing pin clustering with custom coffee shop and park icons on a map of the Seattle area

Screenshot of a Copilot response saying: Sonnet's review was wrong on almost every finding. It reviewed the diff file but apparently looked at the removed lines (old routes without /v1/) instead of the added lines.

A GitHub PR on the dotnet/maui-labs repository showing that a PR titled: Add Linux GTK4 MAUI Backend has been merged a couple of minutes ago.

David Ortinau on stage with a slide that says Microsoft.Maui.Essentials.AI and had all the details about it.

Selfie with the conference venue

Partial screenshot of the GitHub Copilot CLI showing that I have 17.9% requests remaining for this month

Picture taken at .NET MAUI Day last year with the caption: tickets available now, MAUI Day, in-person at NewDay. Central London February 6, 2026.

Partial screenshot of a Copilot chat asking me to confirm if I want to run a command-line prompt. However, the proposed prompt is empty.

Boxes of PC components. Meshify 3, Arctic Liquid Freezer III Pro 360, AMD Ryzen 9950X3D, Corsair RM1000x, Samsung 9100 Pro,
G.Skill Flare X5 and MSI MPG X870E CARBON WIFI

Computer generated graphic showing the Duolingo mascot captioned: I’m a goal crusher! I’m in the top 2% of global learners

A selfie of Gerald with a silly face holding up a copy of Microsoft Azure in Action by Lars Klint.

.NET 10 swag laying on a desk