run-maui-app

name	run-maui-app
description	Build, launch, screenshot, and drive the WinPrint.Maui Windows app (winprint.exe) — including UIA automation of the File button and native Open dialog, and pixel capture that works for WinUI3 content. Use when asked to run, verify, or screenshot the MAUI app.

Run & drive the WinPrint MAUI app (Windows)

Build and launch

dotnet build src/WinPrint.Maui/WinPrint.Maui.csproj -f net10.0-windows10.0.19041.0

The app is unpackaged (WindowsPackageType=None), assembly name winprint:

$exe = "src\WinPrint.Maui\bin\Debug\net10.0-windows10.0.19041.0\win-x64\winprint.exe"
# No args — empty preview; or pass a file to load it on startup:
$proc = Start-Process -FilePath $exe -ArgumentList '"C:\full\path\to\file.cs"' -PassThru

Give it ~6-8 seconds to start. Command-line options mirror the CLI (--landscape, --sheet, --printer, --paper-size; files are positional). Relative file paths are resolved against the launch CWD (MauiProgram.cs captures it before switching CWD to the exe dir).

Verify state (works even on a locked session)

Screenshots lie or fail when the session is locked — UI Automation doesn't. Use:

& .Codex\skills\run-maui-app\scripts\Get-UIState.ps1 -ProcessId $proc.Id

Signals:

• File loaded? The 🖨 Print... button is enabled only when IsFileLoaded && !IsBusy (load failure clears ActiveFile, disabling it). This is the reliable check.
• Title: (Get-Process -Id $proc.Id).MainWindowTitle becomes WinPrint - <name> when the title sync fires. (Historically this did NOT fire for command-line-loaded files because the load starts before the page is attached to its Window — don't treat a stale title alone as "load failed"; check the Print button.)
• The page indicator ("Page x of y") and status text are drawn inside the preview drawable — invisible to UIA. Pixel capture is the only way to see them.

Screenshot (WinUI3 needs PrintWindow + PW_RENDERFULLCONTENT)

& .Codex\skills\run-maui-app\scripts\Capture-Window.ps1 -ProcessId $proc.Id -OutFile out.png

• Graphics.CopyFromScreen returns wallpaper/black if the session is locked (Get-Process LogonUI running ⇒ locked) — don't trust it.
• PrintWindow flag must be 2 (PW_RENDERFULLCONTENT) or WinUI3 composition content comes back black. Even then, captures stay black until the composition surface is poked — a UIA SetFocus on any element in the window reliably unsticks it (waiting and resizing do NOT). The script detects an all-black result, pokes focus, and recaptures automatically.
• Look at the screenshot: a loaded file shows the rendered page with header (date | filename | language), line numbers, and footer ("Page x of y").

Inject keyboard input (works on a locked session)

SendInput/SendKeys can't reach a locked desktop, but posting WM_KEYDOWN/WM_KEYUP to the app's InputSiteWindowClass child hwnd does enter the WinUI3 keyboard pipeline (posting to the top-level hwnd or DesktopChildSiteBridge does NOT). Keys route only if some XAML element has focus — use UIA SetFocus first if needed.

# Find the input-site child hwnd via EnumChildWindows (class "InputSiteWindowClass"),
# then e.g. PageDown (VK_NEXT=0x22, scan 0x51, extended):
$lpDown = [IntPtr](0x1 -bor (0x51 -shl 16) -bor 0x01000000)
$lpUp   = [IntPtr]([long]0x1 -bor (0x51 -shl 16) -bor 0x01000000 -bor 0xC0000000)
[Win32]::PostMessage($inputSite, 0x0100, [IntPtr]0x22, $lpDown)  # WM_KEYDOWN
[Win32]::PostMessage($inputSite, 0x0101, [IntPtr]0x22, $lpUp)    # WM_KEYUP

Verify paging took effect by capturing and reading the drawn footer ("Page x of y"). Note: GetKeyStateForCurrentThread-based modifier checks (Ctrl/Shift) won't see modifiers this way — posted messages don't update the thread keyboard state.

Drive the File button + Open dialog

& .Codex\skills\run-maui-app\scripts\Drive-FileOpen.ps1 -ProcessId $proc.Id -FilePath "C:\full\path\to\README.md"

This UIA-invokes the 📂 File... button, waits for the native Open dialog (a child window of the app window), sets the filename edit (automation id 1148), and clicks Open (automation id 1). Works on a locked session — no real mouse/keyboard input.

Cleanup

$proc.CloseMainWindow()   # polite close; prompts only if sheet settings were edited
# fall back to Stop-Process -Force if it lingers

Closing instances matters: the app persists window state and settings next to the exe on exit, and a leftover instance holds the bin directory, breaking the next build.