ViewModels

ViewModels Reference

Every ViewModel class in PadForge: what it backs, what it exposes, and how state flows between the UI and the services layer.

v3 (2026-04-26): Rewritten for v3. The HIDMaestro SDK surface, OpenXInput shim, thread-pool lifecycle, and bubble-up cascade live on HIDMaestro Deep Dive. If anything here drifts from the live source, the live source wins.

All ViewModels live in PadForge.App/ViewModels/ (PadForge.ViewModels namespace). Built on CommunityToolkit.Mvvm (ObservableObject, RelayCommand).

ViewModelBase

File: ViewModelBase.cs

Abstract base class for all ViewModels. Extends ObservableObject (INotifyPropertyChanged, SetProperty).

public abstract class ViewModelBase : ObservableObject
{
    private string _title = string.Empty;

    public string Title
    {
        get => _title;
        set => SetProperty(ref _title, value);
    }
}

Property	Type	Description
`Title`	`string`	Display title for the view. Used by navigation and page headers.

Culture / Localization

The constructor subscribes to Strings.CultureChanged for live language switching. When the UI language changes, every ViewModel's OnCultureChanged() runs, letting derived classes refresh culture-dependent text.

Strings.CultureChanged uses a weak event pattern. Instance-method subscribers are stored as (WeakReference<Target>, MethodInfo) pairs, so short-lived ViewModels can be garbage-collected without unsubscribing. Dead entries are pruned on each raise. Static-method subscribers use strong references.

protected ViewModelBase()
{
    Strings.CultureChanged += OnCultureChanged;  // weak. No GC leak
}

protected virtual void OnCultureChanged() { }

NavControllerItemViewModel

File: MainViewModel.cs (defined alongside MainViewModel)

Sidebar entry for one virtual controller. Shows controller type icon, slot number, and per-type instance label.

Property	Type	Description
`PadIndex`	`int`	Zero-based pad slot index (0–15). Read-only.
`Tag`	`string`	Navigation tag (`"Pad1"`–`"Pad16"`). Computed as `$"Pad{PadIndex + 1}"`.
`SlotNumber`	`int`	1-based controller number among active slots.
`InstanceLabel`	`string`	Per-type instance label (e.g., `"1"`, `"2"`).
`IconKey`	`string`	Resource key for controller type icon (e.g., `"XboxControllerIcon"`, `"DS4ControllerIcon"`, `"ExtendedControllerIcon"`, `"MidiControllerIcon"`, `"KeyboardMouseControllerIcon"`).
`IsEnabled`	`bool`	Virtual controller enabled.
`ConnectedDeviceCount`	`int`	Mapped physical devices connected.
`IsInitializing`	`bool`	Virtual controller initializing.
`IsVirtualControllerConnected`	`bool`	Live virtual controller is alive (created + reporting `IsConnected`). Drives the sidebar green-vs-yellow indicator so the slot stays green through the HM-inactivity grace window and only turns yellow once the timeout tears the VC down.

XAML binding: Sidebar ListBox binds to MainViewModel.NavControllerItems. Each template binds SlotNumber, InstanceLabel, IconKey (via DynamicResource), and IsEnabled.

MainViewModel

File: MainViewModel.cs DataContext for: MainWindow

Root ViewModel. Manages navigation state, 16 pad ViewModels, sidebar controller entries, and app-wide status.

Child ViewModels

Property	Type	Description
`Pads`	`ObservableCollection<PadViewModel>`	16 pad ViewModels (one per slot). Created in constructor.
`NavControllerItems`	`ObservableCollection<NavControllerItemViewModel>`	Sidebar items for created slots. Rebuilt by `RefreshNavControllerItems()`.
`Dashboard`	`DashboardViewModel`	Dashboard overview ViewModel.
`Devices`	`DevicesViewModel`	Devices list ViewModel.
`Settings`	`SettingsViewModel`	Application settings ViewModel.

Navigation Properties

Property	Type	Description
`SelectedNavTag`	`string`	Current nav tag: `"Dashboard"`, `"Pad1"`–`"Pad16"`, `"Devices"`, `"Settings"`, `"About"`. Also notifies `IsPadPageSelected` and `SelectedPadIndex`.
`IsPadPageSelected`	`bool`	True if a Pad page (Pad1–Pad16) is selected. Computed.
`SelectedPadIndex`	`int`	Zero-based pad index for the selected Pad page, or -1. Computed.
`SelectedPad`	`PadViewModel`	PadViewModel for the selected Pad page, or null. Computed.

App-wide Status Properties

Property	Type	Default	Description
`StatusText`	`string`	`"Ready"`	Status bar text.
`IsEngineRunning`	`bool`	`false`	Polling loop active. Calls `RefreshEngineStatus()`.
`HasActiveSlots`	`bool`	`false`	Any virtual controller slots exist. Calls `RefreshEngineStatus()`.
`EngineStatusText`	`string`	-	Computed: `"Running"` / `"Idle"` / `"Stopped"` based on engine and slot state.
`EngineStatusBrush`	`Brush`	-	Computed: Red (#F44336) = Stopped, Amber (#FFB300) = Idle (engine running, no created slots), Green (#4CAF50) = Running with active slots. Frozen (thread-safe).
`PollingFrequency`	`double`	`0`	Current polling frequency in Hz.
`ConnectedDeviceCount`	`int`	`0`	Connected input device count.

Commands

Command	CanExecute	Description
`StartEngineCommand`	`!IsEngineRunning`	Raises `StartEngineRequested`. Wired by MainWindow code-behind.
`StopEngineCommand`	`IsEngineRunning`	Raises `StopEngineRequested`.

Events

Event	Args	Description
`StartEngineRequested`	`EventArgs`	Start engine.
`StopEngineRequested`	`EventArgs`	Stop engine.
`NavControllerItemsRefreshed`	`EventArgs`	Raised after `RefreshNavControllerItems()` completes. MainWindow uses this instead of `CollectionChanged` to avoid rapid sidebar rebuilds.

Key Methods

Method	Description
`RefreshNavControllerItems()`	Rebuilds sidebar entries from `SettingsManager.SlotCreated[]`. Computes per-type instance numbers and updates each pad's `Title`, `SlotLabel`, `TypeInstanceLabel`. Raises `NavControllerItemsRefreshed` only on slot add/remove.
`ForceNavControllerItemsRefreshed()`	Forces `NavControllerItemsRefreshed` even when slot count is unchanged. Used after reorder/swap.
`RefreshEngineStatus()`	Notifies `EngineStatusText` and `EngineStatusBrush`.
`RefreshCommands()`	Notifies `CanExecuteChanged` on start/stop commands. Call after `IsEngineRunning` changes.

DashboardViewModel

File: DashboardViewModel.cs DataContext for: Dashboard page

Overview of all controller slots, engine status, connected devices, and driver status.

Slot Summaries

Property	Type	Description
`SlotSummaries`	`ObservableCollection<SlotSummary>`	Cards for created slots. Rebuilt by `RefreshActiveSlots()`.
`ShowAddController`	`bool`	"Add Controller" visible (any type has capacity).

Engine Status

Property	Type	Default	Description
`EngineStatus`	`string`	`"Stopped"`	Localized engine status.
`EngineStateKey`	`string`	`"Stopped"`	Non-localized state key (`"Running"`, `"Stopped"`, `"Idle"`) for XAML DataTriggers.
`PollingFrequency`	`double`	`0`	Polling frequency in Hz. Also notifies `PollingFrequencyText`.
`PollingFrequencyText`	`string`	-	Computed: formatted frequency (e.g., `"987.3 Hz"`) or dash when zero.

Device Counts

Property	Type	Description
`TotalDevices`	`int`	Total detected devices (online + offline).
`OnlineDevices`	`int`	Currently connected devices.
`MappedDevices`	`int`	Devices with an active slot mapping.

Driver Status

HIDMaestro is bundled with PadForge as a managed SDK and ships with the executable, so the dashboard does not surface an install/uninstall row for it. HidHide and Windows MIDI Services are optional system drivers and have their own rows.

Property	Type	Description
`IsHidHideInstalled`	`bool`	HidHide installed. Notifies `HidHideStatusText`.
`HidHideStatusText`	`string`	Computed: `"Installed"` / `"Not installed"`.
`IsMidiServicesInstalled`	`bool`	Windows MIDI Services installed. Notifies `MidiServicesStatusText`.
`MidiServicesStatusText`	`string`	Computed: `"Installed"` / `"Not installed"`.

DSU Motion Server

Property	Type	Default	Description
`EnableDsuMotionServer`	`bool`	`false`	DSU (cemuhook) motion server enabled.
`DsuMotionServerPort`	`int`	`26760`	UDP port. Clamped to 1024–65535.
`DsuServerStatus`	`string`	`"Stopped"`	DSU server status.

Web Controller Server

Property	Type	Default	Description
`EnableWebController`	`bool`	`false`	Web controller server enabled.
`WebControllerPort`	`int`	`8080`	HTTP/WebSocket port. Clamped to 1024–65535.
`WebControllerStatus`	`string`	`"Stopped"`	Web controller server status.
`WebControllerClientCount`	`int`	`0`	Connected web controller clients.

Touchpad Overlay (3.2)

On-screen transparent touchpad window that drives the DS4 / DualSense touchpad on the assigned PlayStation slot.

Property	Type	Default	Description
`EnableTouchpadOverlay`	`bool`	`false`	Overlay visible.
`TouchpadOverlayOpacity`	`double`	`0.25`	Surface opacity 0.0–1.0. Notifies `TouchpadOverlayOpacityPercent`.
`TouchpadOverlayOpacityPercent`	`int`	`25`	0–100 integer view of opacity for NumberBox binding.
`TouchpadOverlayMonitor`	`int`	`0`	Monitor index the overlay is pinned to (0 = primary).
`TouchpadOverlayLeft` / `Top`	`double`	`-1`	Window position. `-1` = centered on the chosen monitor.
`TouchpadOverlayWidth` / `Height`	`double`	`500` / `250`	Window size. Clamped to `>= 150` and `>= 80` respectively.
`IsTouchpadOverlayRunning`	`bool`	`false`	Overlay window currently shown. Drives `TouchpadOverlayStatus`.
`TouchpadOverlayStatus`	`string`	-	Localized status string (`"Running"` / `"Stopped"`).

Command	Description
`ResetOpacityCommand`	Resets opacity to default 0.25.
`ResetTouchpadOverlayPositionCommand`	Raises `ResetTouchpadOverlayPositionRequested`. `InputService` recenters the live overlay (or seeds defaults if not open) and clears persisted `Left` / `Top`.

Event	Description
`ResetTouchpadOverlayPositionRequested`	Recenter request from the UI.

Key Methods

Method	Description
`RefreshActiveSlots(IList<int>, bool)`	Rebuilds `SlotSummaries` for active slots. Updates display labels, sets `ShowAddController`. Called by InputService.

SlotSummary

File: DashboardViewModel.cs (nested class)

Summary card for one virtual controller slot on the Dashboard.

Property	Type	Default	Description
`PadIndex`	`int`	-	Zero-based slot index. Read-only.
`SlotLabel`	`string`	-	Display label (e.g., `"Virtual Controller 1"`).
`DeviceName`	`string`	`"No device"`	Primary mapped device name.
`IsActive`	`bool`	`false`	Has at least one online mapped device.
`IsVirtualControllerConnected`	`bool`	`false`	Virtual controller connected.
`IsInitializing`	`bool`	`false`	Virtual controller initializing.
`MappedDeviceCount`	`int`	`0`	Devices mapped to this slot.
`ConnectedDeviceCount`	`int`	`0`	Mapped devices connected.
`StatusText`	`string`	`"Idle"`	Status: `"Active"`, `"Idle"`, `"No mapping"`, or `"Disabled"`.
`IsEnabled`	`bool`	`true`	Slot enabled for output.
`SlotNumber`	`int`	`1`	1-based controller number among active slots.
`TypeInstanceLabel`	`string`	`"1"`	Per-type instance label.
`OutputType`	`VirtualControllerType`	`Xbox`	Virtual controller output type. (XML on-disk name is `"Microsoft"` via `[XmlEnum]` for v2/early-v3 back-compat; in-code identifier is `Xbox`.)

SettingsViewModel

File: SettingsViewModel.cs DataContext for: Settings page

Application-level settings: theme, language, drivers, profiles, and engine configuration.

Theme

Property	Type	Default	Description
`SelectedThemeIndex`	`int`	`0`	0 = System, 1 = Light, 2 = Dark. Raises `ThemeChanged`.

Event	Args	Description
`ThemeChanged`	`int`	Raised when theme selection changes. Arg = theme index.

Language

Property	Type	Description
`AvailableLanguages`	`ObservableCollection<CultureInfo>`	UI languages: en, de, fr, ja, ko, zh-Hans, pt-BR, es, it, nl.
`SelectedLanguage`	`CultureInfo`	Current UI language. Applies immediately via `Strings.ChangeCulture()`. Defaults to current culture or English.

Member	Type	Description
`LanguageCode`	`string`	Persisted language code for serialization.
`SetLanguageFromCode(string)`	method	Sets language from persisted code on startup without raising `CultureChanged`.

Driver Status: HIDMaestro

HIDMaestro is shipped as an embedded managed SDK (HIDMaestro.Core, bundled at Resources/HIDMaestro/HIDMaestro.Core.dll). The user-mode driver still needs to be registered with Windows once. That happens inside the engine via HMContext.InstallDriver() (called from InputManager.Step5.VirtualDevices.cs:EnsureHMaestroContext), not through DriverInstaller. The SettingsViewModel exposes a read-only version string read from the bundled assembly at startup.

Property	Type	Description
`HIDMaestroVersion`	`string`	HIDMaestro SDK version. Initialized from the embedded `HIDMaestro.Core` assembly via `GetEmbeddedHidMaestroVersion()`.

Driver Status: HidHide

Property	Type	Description
`IsHidHideInstalled`	`bool`	HidHide installed.
`HidHideStatusText`	`string`	Computed: `"Installed"` / `"Not installed"`.
`HidHideVersion`	`string`	HidHide version.
`HidHideWhitelistPaths`	`ObservableCollection<string>`	Whitelisted application paths.
`SelectedWhitelistPath`	`string`	Selected whitelist path. Refreshes `RemoveWhitelistPathCommand`.

Command	CanExecute	Description
`InstallHidHideCommand`	`!IsHidHideInstalled`	Raises `InstallHidHideRequested`.
`UninstallHidHideCommand`	`IsHidHideInstalled && !HasAnyHidHideDevices()`	Raises `UninstallHidHideRequested`.
`AddWhitelistPathCommand`	`IsHidHideInstalled`	Raises `AddWhitelistPathRequested`.
`RemoveWhitelistPathCommand`	`SelectedWhitelistPath != null`	Removes selected path, raises `WhitelistChanged`.

Event	Description
`InstallHidHideRequested`	Install HidHide.
`UninstallHidHideRequested`	Uninstall HidHide.
`AddWhitelistPathRequested`	Add whitelist path (opens file dialog).
`WhitelistChanged`	Whitelist was modified (add or remove).

Driver Status: Windows MIDI Services

Property	Type	Description
`IsMidiServicesInstalled`	`bool`	Windows MIDI Services available.
`MidiServicesStatusText`	`string`	Computed: `"Installed"` / `"Not installed"`.
`MidiServicesVersion`	`string`	MIDI Services version.
`IsMidiOsSupported`	`bool`	Static: `true` if OS build >= 26100 (Win11 24H2).

Command	CanExecute	Description
`InstallMidiServicesCommand`	`!IsMidiServicesInstalled && IsMidiOsSupported`	Raises `InstallMidiServicesRequested`.
`UninstallMidiServicesCommand`	`IsMidiServicesInstalled && !HasAnyMidiSlots()`	Raises `UninstallMidiServicesRequested`.

Driver Uninstall Guards

Member	Type	Description
`HasAnyMidiSlots`	`Func<bool>`	Set by MainWindow. True if any slot uses MIDI. Blocks `UninstallMidiServicesCommand`.
`HasAnyHidHideDevices`	`Func<bool>`	Set by MainWindow. True if any device has HidHide enabled. Blocks `UninstallHidHideCommand`.
`RefreshDriverGuards()`	method	Re-evaluates uninstall `CanExecute` for HidHide and MIDI Services. Call after slot creation/deletion/type changes.

Engine Settings

Property	Type	Default	Description
`AutoStartEngine`	`bool`	`true`	Auto-start engine on launch.
`MinimizeToTray`	`bool`	`false`	Minimize to system tray instead of taskbar.
`StartMinimized`	`bool`	`false`	Start minimized.
`StartAtLogin`	`bool`	`false`	Auto-start at login.
`EnablePollingOnFocusLoss`	`bool`	`true`	Continue polling on focus loss.
`PollingRateMs`	`int`	`1`	Polling interval in ms. Clamped to 1–16.
`HmInactivityDestroyTimeoutSeconds`	`int`	`60`	Seconds the engine waits for any mapped device to return online before tearing down the live HM virtual controller and freeing its kernel slot. Clamped to 0–3600. `0` disables the timeout. The slot's configuration (mappings, profile, position, enabled state) is preserved end-to-end. Only the live VC is destroyed. Once mapped devices come back online, the VC recreates automatically at the same visual position. Surviving Xbox HM VCs at higher visual positions bubble down to keep xinputhid indices contiguous after the teardown.
`EnableInputHiding`	`bool`	`true`	Master switch for device hiding (HidHide + input hooks).
`KeepHidHideCloaksBetweenLaunches`	`bool`	`false`	When true, HidHide cloaks stay asserted after PadForge exits so other apps still see the physical devices hidden. When false (default), cloaks clear on shutdown.

Settings File

Property	Type	Description
`SettingsFilePath`	`string`	Path to the loaded settings file.
`HasUnsavedChanges`	`bool`	Unsaved changes exist.

Command	Description
`SaveCommand`	Raises `SaveRequested`.
`ReloadCommand`	Raises `ReloadRequested`.
`ResetCommand`	Raises `ResetRequested`.
`OpenSettingsFolderCommand`	Raises `OpenSettingsFolderRequested`.

Event	Description
`SaveRequested`	Save settings.
`ReloadRequested`	Reload from disk.
`ResetRequested`	Reset settings.
`OpenSettingsFolderRequested`	Open settings folder.

Diagnostic Info

Property	Type	Description
`SdlVersion`	`string`	SDL3 version.
`ApplicationVersion`	`string`	Application version.
`RuntimeVersion`	`string`	.NET runtime version.

Display Preferences

Property	Type	Default	Description
`Use2DControllerView`	`bool`	`false`	Show 2D controller view instead of 3D.

Profiles

Property	Type	Default	Description
`EnableAutoProfileSwitching`	`bool`	`false`	Auto-profile switching enabled.
`ProfileItems`	`ObservableCollection<ProfileListItem>`	empty	Profile entries for UI list.
`SelectedProfile`	`ProfileListItem`	`null`	Selected profile. Refreshes delete/edit/load commands.
`ActiveProfileInfo`	`string`	`"Default"`	Active profile display text.

Command	CanExecute	Description
`NewProfileCommand`	always	Raises `NewProfileRequested`.
`SaveAsProfileCommand`	always	Raises `SaveAsProfileRequested`.
`DeleteProfileCommand`	`SelectedProfile != null && !IsDefault`	Raises `DeleteProfileRequested`.
`EditProfileCommand`	`SelectedProfile != null && !IsDefault`	Raises `EditProfileRequested`.
`LoadProfileCommand`	`SelectedProfile != null`	Raises `LoadProfileRequested` or `RevertToDefaultRequested` if default.

Event	Description
`RevertToDefaultRequested`	Revert to default profile.
`NewProfileRequested`	Create new empty profile.
`SaveAsProfileRequested`	Save current settings as profile.
`DeleteProfileRequested`	Delete selected profile.
`EditProfileRequested`	Edit selected profile metadata.
`LoadProfileRequested`	Load selected profile.

Method	Description
`RefreshProfileCommands()`	Refreshes `CanExecute` for delete/edit/load commands.

ProfileListItem

File: SettingsViewModel.cs (nested class)

Display item for a profile in the Settings list.

Property	Type	Description
`Id`	`string`	Profile identifier.
`Name`	`string`	Display name.
`Executables`	`string`	Comma-separated exe names for auto-switch.
`TopologyLabel`	`string`	Slot topology summary.
`HasNoSlots`	`bool`	Computed: all type counts are zero.
`XboxCount`	`int`	Number of Xbox slots in this profile.
`PlayStationCount`	`int`	Number of PlayStation slots.
`ExtendedCount`	`int`	Number of Extended slots.
`MidiCount`	`int`	Number of MIDI slots.
`KbmCount`	`int`	Number of Keyboard+Mouse slots.
`IsDefault`	`bool`	Computed: true if `Id == "__default__"`.

Constant	Value	Description
`DefaultProfileId`	`"__default__"`	Sentinel ID for the Default profile.

DevicesViewModel

File: DevicesViewModel.cs DataContext for: Devices page

All detected input devices (online and offline) with raw input state for the selected device.

Device List

Property	Type	Description
`Devices`	`ObservableCollection<DeviceRowViewModel>`	All known devices. Updated by InputService on change.
`SelectedDevice`	`DeviceRowViewModel`	Selected device. Notifies `HasSelectedDevice`, refreshes slot buttons and command state.
`HasSelectedDevice`	`bool`	Computed: `SelectedDevice != null`.

Device Counts

Property	Type	Description
`TotalCount`	`int`	Total detected devices.
`OnlineCount`	`int`	Connected devices.

Raw Input State Display (for selected device)

Property	Type	Description
`RawAxes`	`ObservableCollection<AxisDisplayItem>`	Axis values (progress bars).
`RawButtons`	`ObservableCollection<ButtonDisplayItem>`	Button states (circles).
`RawPovs`	`ObservableCollection<PovDisplayItem>`	POV hat values (compass).
`KeyboardKeys`	`ObservableCollection<KeyboardKeyItem>`	Keyboard layout items.
`IsKeyboardDevice`	`bool`	Selected device is a keyboard.
`IsMouseDevice`	`bool`	Selected device is a mouse.
`IsTouchpadDevice`	`bool`	Selected device exposes a touchpad surface (DS4 / DualSense / Steam Controller / Steam Deck / overlay touchpad).
`HasTouchpadData`	`bool`	At least one finger is currently in contact.
`TouchpadX0` / `TouchpadY0`	`double`	First finger normalized position (0.0–1.0).
`TouchpadX1` / `TouchpadY1`	`double`	Second finger normalized position.
`TouchpadDown0` / `TouchpadDown1`	`bool`	Per-finger contact state.
`MouseMotionX`	`double`	Mouse X motion.
`MouseMotionY`	`double`	Mouse Y motion.
`MouseScrollIntensity`	`double`	Normalized scroll intensity (−1 to 1).
`SelectedButtonTotal`	`int`	Button count on selected device.
`HasRawData`	`bool`	Raw state data available.

Gyroscope / Accelerometer

Property	Type	Description
`HasGyroData`	`bool`	Gyroscope data available.
`HasAccelData`	`bool`	Accelerometer data available.
`GyroX`	`double`	Gyroscope X value.
`GyroY`	`double`	Gyroscope Y value.
`GyroZ`	`double`	Gyroscope Z value.
`AccelX`	`double`	Accelerometer X value.
`AccelY`	`double`	Accelerometer Y value.
`AccelZ`	`double`	Accelerometer Z value.

Dynamic Slot Assignment Buttons

Property	Type	Description
`ActiveSlotItems`	`ObservableCollection<SlotButtonItem>`	Slot toggle buttons. Only includes created/active slots.

Commands

Command	CanExecute	Description
`RefreshCommand`	always	Raises `RefreshRequested`. Force-refreshes device list.
`AssignToSlotCommand`	`HasSelectedDevice`	`RelayCommand<int>`. Raises `AssignToSlotRequested` with slot index (0–15).
`ToggleSlotCommand`	`HasSelectedDevice`	`RelayCommand<int>`. Toggles slot assignment. Raises `ToggleSlotRequested`.
`HideDeviceCommand`	`HasSelectedDevice`	Sets `IsHidden = true`, raises `HideDeviceRequested`.
`RemoveDeviceCommand`	`HasSelectedDevice`	Removes device, raises `RemoveDeviceRequested`.

Events

Event	Args	Description
`RefreshRequested`	`EventArgs`	Refresh requested.
`AssignToSlotRequested`	`int`	Slot index.
`ToggleSlotRequested`	`int`	Slot index.
`HideDeviceRequested`	`Guid`	Instance GUID.
`RemoveDeviceRequested`	`Guid`	Instance GUID.
`DeviceHidingChanged`	`Guid`	HidHide or ConsumeInput toggle changed.

Key Methods

Method	Description
`RebuildRawStateCollections(int, int, int, bool, bool)`	Rebuilds axis/button/POV collections for a new device. Handles keyboard and mouse cases.
`ClearRawState()`	Clears all raw state display data.
`RefreshSlotButtons()`	Rebuilds `ActiveSlotItems` from created slots and selected device assignments.
`FindByGuid(Guid)`	Finds a `DeviceRowViewModel` by instance GUID.
`RefreshCounts()`	Updates `TotalCount` and `OnlineCount`.
`NotifyDeviceHidingChanged(Guid)`	Raises `DeviceHidingChanged`.