Extract SensorSelectionService from MainWindowViewModel

Moves tray/gadget sensor selection (the per-sensor 'tray'/'gadget' settings,
their key convention, and the GadgetSensorsChanged/TraySensorsChanged events)
into a focused, testable collaborator. The view model keeps thin delegating
methods and forwards the events, so its public surface (used by MainWindow) is
unchanged. Behavior is unchanged.

Adds 3 tests (persistence round-trip, event raising, tray filtering).

196 tests pass (was 193).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

LibreHardwareMonitor.Windows.WinUI.Tests/ViewModels/SensorSelectionServiceTests.cs

@@ -0,0 +1,83 @@
+// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
+// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+// Copyright (C) LibreHardwareMonitor and Contributors.
+
+using System.Linq;
+using LibreHardwareMonitor.Hardware;
+using LibreHardwareMonitor.Windows.WinUI.Services;
+using LibreHardwareMonitor.Windows.WinUI.ViewModels;
+using Moq;
+using Xunit;
+
+namespace LibreHardwareMonitor.Windows.WinUI.Tests.ViewModels;
+
+public class SensorSelectionServiceTests
+{
+    [Fact]
+    public void SetSensorInTray_PersistsReadsBack_AndRaisesEvent()
+    {
+        (SensorSelectionService service, _, SensorTreeItemViewModel item) = Build();
+        int raised = 0;
+        service.TraySensorsChanged += (_, _) => raised++;
+
+        service.SetSensorInTray(item, true);
+        Assert.True(service.IsSensorInTray(item));
+
+        service.SetSensorInTray(item, false);
+        Assert.False(service.IsSensorInTray(item));
+
+        Assert.Equal(2, raised);
+    }
+
+    [Fact]
+    public void SetSensorInGadget_PersistsReadsBack_AndRaisesEvent()
+    {
+        (SensorSelectionService service, _, SensorTreeItemViewModel item) = Build();
+        int raised = 0;
+        service.GadgetSensorsChanged += (_, _) => raised++;
+
+        service.SetSensorInGadget(item, true);
+        Assert.True(service.IsSensorInGadget(item));
+
+        service.SetSensorInGadget(item, false);
+        Assert.False(service.IsSensorInGadget(item));
+
+        Assert.Equal(2, raised);
+    }
+
+    [Fact]
+    public void GetTraySensorItems_ReturnsOnlyTrayFlaggedSensors()
+    {
+        (SensorSelectionService service, SensorTreeItemViewModel root, SensorTreeItemViewModel item) = Build();
+
+        service.SetSensorInTray(item, true);
+        Assert.Contains(item, service.GetTraySensorItems(root));
+
+        service.SetSensorInTray(item, false);
+        Assert.DoesNotContain(item, service.GetTraySensorItems(root));
+    }
+
+    private static (SensorSelectionService Service, SensorTreeItemViewModel Root, SensorTreeItemViewModel SensorItem) Build()
+    {
+        AppSettings settings = AppSettings.LoadDefault();
+
+        var hardwareMock = new Mock<IHardware>();
+        var sensorMock = new Mock<ISensor>();
+        sensorMock.Setup(s => s.Name).Returns("Sensor");
+        sensorMock.Setup(s => s.SensorType).Returns(SensorType.Temperature);
+        sensorMock.Setup(s => s.Index).Returns(0);
+        sensorMock.Setup(s => s.Identifier).Returns(new Identifier("cpu", "0", "temperature", "0"));
+
+        hardwareMock.Setup(h => h.Name).Returns("CPU");
+        hardwareMock.Setup(h => h.HardwareType).Returns(HardwareType.Cpu);
+        hardwareMock.Setup(h => h.Identifier).Returns(new Identifier("cpu", "0"));
+        hardwareMock.Setup(h => h.Sensors).Returns([sensorMock.Object]);
+        hardwareMock.Setup(h => h.SubHardware).Returns([]);
+
+        var root = SensorTreeItemViewModel.CreateRoot("HOST");
+        root.Children.Add(SensorTreeItemViewModel.FromHardware(hardwareMock.Object, settings));
+        SensorTreeItemViewModel sensorItem = root.EnumerateSensors().First();
+
+        return (new SensorSelectionService(settings), root, sensorItem);
+    }
+}

LibreHardwareMonitor.Windows.WinUI/ViewModels/MainWindowViewModel.cs

@@ -85,6 +85,7 @@ public sealed class MainWindowViewModel : ViewModelBase, IDisposable
     private readonly DispatcherQueue _dispatcherQueue;
     private readonly Logger _logger;
     private readonly PlotTrackingService _plotTracking = new();
+    private readonly SensorSelectionService _sensorSelection;
     private readonly RemoteWebServer _remoteWebServer;
     private readonly StartupService _startupService = new();
     private readonly WinUiStartupTrace? _startupTrace;
@@ -125,6 +126,7 @@ public sealed class MainWindowViewModel : ViewModelBase, IDisposable
         _dispatcherQueue = DispatcherQueue.GetForCurrentThread();
         _hardwareMonitor = new HardwareMonitorService(settings);
         _logger = new Logger(_hardwareMonitor.Computer);
+        _sensorSelection = new SensorSelectionService(settings);
         _remoteWebServer = new RemoteWebServer(
             () => RootItems.FirstOrDefault(),
             _hardwareMonitor.Computer,
@@ -163,9 +165,17 @@ public sealed class MainWindowViewModel : ViewModelBase, IDisposable
 
     public event EventHandler? PlotInvalidated;
 
-    public event EventHandler? GadgetSensorsChanged;
+    public event EventHandler? GadgetSensorsChanged
+    {
+        add => _sensorSelection.GadgetSensorsChanged += value;
+        remove => _sensorSelection.GadgetSensorsChanged -= value;
+    }
 
-    public event EventHandler? TraySensorsChanged;
+    public event EventHandler? TraySensorsChanged
+    {
+        add => _sensorSelection.TraySensorsChanged += value;
+        remove => _sensorSelection.TraySensorsChanged -= value;
+    }
 
     public Visibility MaxColumnVisibility => ShowMaxColumn ? Visibility.Visible : Visibility.Collapsed;
 
@@ -789,42 +799,32 @@ public sealed class MainWindowViewModel : ViewModelBase, IDisposable
 
     public bool IsSensorInGadget(SensorTreeItemViewModel item)
     {
-        return item.Sensor != null && Settings.GetValue(GetSensorSettingName(item.Sensor, "gadget"), false);
+        return _sensorSelection.IsSensorInGadget(item);
     }
 
     public bool IsSensorInTray(SensorTreeItemViewModel item)
     {
-        return item.Sensor != null && Settings.GetValue(GetSensorSettingName(item.Sensor, "tray"), false);
+        return _sensorSelection.IsSensorInTray(item);
     }
 
     public IEnumerable<SensorTreeItemViewModel> GetGadgetSensorItems()
     {
-        return RootItems.FirstOrDefault()?.EnumerateSensors().Where(IsSensorInGadget) ?? [];
+        return _sensorSelection.GetGadgetSensorItems(RootItems.FirstOrDefault());
     }
 
     public IEnumerable<SensorTreeItemViewModel> GetTraySensorItems()
     {
-        return RootItems.FirstOrDefault()?.EnumerateSensors().Where(IsSensorInTray) ?? [];
+        return _sensorSelection.GetTraySensorItems(RootItems.FirstOrDefault());
     }
 
     public void SetSensorInGadget(SensorTreeItemViewModel item, bool value)
     {
-        if (item.Sensor == null)
-            return;
-
-        SetSensorBooleanSetting(item.Sensor, "gadget", value);
-        GadgetSensorsChanged?.Invoke(this, EventArgs.Empty);
+        _sensorSelection.SetSensorInGadget(item, value);
     }
 
     public void SetSensorInTray(SensorTreeItemViewModel item, bool value)
     {
-        if (item.Sensor == null)
-            return;
-
-        SetSensorBooleanSetting(item.Sensor, "tray", value);
-        if (!value)
-            Settings.Remove(GetSensorSettingName(item.Sensor, "traycolor"));
-        TraySensorsChanged?.Invoke(this, EventArgs.Empty);
+        _sensorSelection.SetSensorInTray(item, value);
     }
 
     public void SetSensorPenColor(SensorTreeItemViewModel item, Color? color)
@@ -1001,20 +1001,6 @@ public sealed class MainWindowViewModel : ViewModelBase, IDisposable
         OnPropertyChanged();
     }
 
-    private void SetSensorBooleanSetting(ISensor sensor, string suffix, bool value)
-    {
-        string settingName = GetSensorSettingName(sensor, suffix);
-        if (value)
-            Settings.SetValue(settingName, true);
-        else
-            Settings.Remove(settingName);
-    }
-
-    private static string GetSensorSettingName(ISensor sensor, string suffix)
-    {
-        return new Identifier(sensor.Identifier, suffix).ToString();
-    }
-
     private void SetHardwareFlag(bool value, bool currentValue, Action<bool> setValue)
     {
         if (currentValue == value)

LibreHardwareMonitor.Windows.WinUI/ViewModels/SensorSelectionService.cs

@@ -0,0 +1,84 @@
+// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
+// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+// Copyright (C) LibreHardwareMonitor and Contributors.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using LibreHardwareMonitor.Hardware;
+using LibreHardwareMonitor.Windows.WinUI.Services;
+
+namespace LibreHardwareMonitor.Windows.WinUI.ViewModels;
+
+/// <summary>
+/// Tracks which sensors the user has chosen to show in the system-tray icons and in the desktop gadget, persisting each
+/// choice as a per-sensor setting. Extracted from <see cref="MainWindowViewModel" /> to keep that selection concern (and
+/// its settings-key convention) in one testable place.
+/// </summary>
+internal sealed class SensorSelectionService
+{
+    private readonly AppSettings _settings;
+
+    public SensorSelectionService(AppSettings settings)
+    {
+        _settings = settings;
+    }
+
+    public event EventHandler? GadgetSensorsChanged;
+
+    public event EventHandler? TraySensorsChanged;
+
+    public bool IsSensorInGadget(SensorTreeItemViewModel item)
+    {
+        return item.Sensor != null && _settings.GetValue(GetSensorSettingName(item.Sensor, "gadget"), false);
+    }
+
+    public bool IsSensorInTray(SensorTreeItemViewModel item)
+    {
+        return item.Sensor != null && _settings.GetValue(GetSensorSettingName(item.Sensor, "tray"), false);
+    }
+
+    public IEnumerable<SensorTreeItemViewModel> GetGadgetSensorItems(SensorTreeItemViewModel? root)
+    {
+        return root?.EnumerateSensors().Where(IsSensorInGadget) ?? [];
+    }
+
+    public IEnumerable<SensorTreeItemViewModel> GetTraySensorItems(SensorTreeItemViewModel? root)
+    {
+        return root?.EnumerateSensors().Where(IsSensorInTray) ?? [];
+    }
+
+    public void SetSensorInGadget(SensorTreeItemViewModel item, bool value)
+    {
+        if (item.Sensor == null)
+            return;
+
+        SetSensorBooleanSetting(item.Sensor, "gadget", value);
+        GadgetSensorsChanged?.Invoke(this, EventArgs.Empty);
+    }
+
+    public void SetSensorInTray(SensorTreeItemViewModel item, bool value)
+    {
+        if (item.Sensor == null)
+            return;
+
+        SetSensorBooleanSetting(item.Sensor, "tray", value);
+        if (!value)
+            _settings.Remove(GetSensorSettingName(item.Sensor, "traycolor"));
+        TraySensorsChanged?.Invoke(this, EventArgs.Empty);
+    }
+
+    public static string GetSensorSettingName(ISensor sensor, string suffix)
+    {
+        return new Identifier(sensor.Identifier, suffix).ToString();
+    }
+
+    private void SetSensorBooleanSetting(ISensor sensor, string suffix, bool value)
+    {
+        string settingName = GetSensorSettingName(sensor, suffix);
+        if (value)
+            _settings.SetValue(settingName, true);
+        else
+            _settings.Remove(settingName);
+    }
+}