Refactor SelectedTab to DeclarativeProperty

src/AppCommon/FileTime.App.Core.Abstraction/ViewModels/IAppState.cs

@@ -8,16 +8,15 @@ namespace FileTime.App.Core.ViewModels;
 public interface IAppState
 {
     ReadOnlyObservableCollection<ITabViewModel> Tabs { get; }
-    IObservable<ITabViewModel?> SelectedTab { get; }
+    IDeclarativeProperty<ITabViewModel?> SelectedTab { get; }
     IObservable<string?> SearchText { get; }
     IDeclarativeProperty<ViewMode> ViewMode { get; }
     DeclarativeProperty<string?> RapidTravelText { get; }
-    ITabViewModel? CurrentSelectedTab { get; }
     ITimelineViewModel TimelineViewModel { get; }
 
     void AddTab(ITabViewModel tabViewModel);
     void RemoveTab(ITabViewModel tabViewModel);
     void SetSearchText(string? searchText);
     Task SwitchViewModeAsync(ViewMode newViewMode);
-    void SetSelectedTab(ITabViewModel tabToSelect);
+    Task SetSelectedTabAsync(ITabViewModel tabToSelect);
 }

src/AppCommon/FileTime.App.Core/Services/Persistence/TabPersistenceService.cs

@@ -177,7 +177,7 @@ public class TabPersistenceService : ITabPersistenceService
             .SkipWhile(t => t.TabNumber <= tabStates.ActiveTabNumber);
 
         var tabToActivate = optimalTabs.Concat(suboptimalTabs).FirstOrDefault();
-        if (tabToActivate is not null) _appState.SetSelectedTab(tabToActivate);
+        if (tabToActivate is not null) await _appState.SetSelectedTabAsync(tabToActivate);
 
         return true;
     }
@@ -205,7 +205,7 @@ public class TabPersistenceService : ITabPersistenceService
 
         return new TabStates(
             tabStates,
-            _appState.CurrentSelectedTab?.TabNumber
+            _appState.SelectedTab.Value?.TabNumber
         );
     }
 

src/AppCommon/FileTime.App.Core/Services/UserCommandHandler/NavigationUserCommandHandlerService.cs

@@ -345,7 +345,7 @@ public class NavigationUserCommandHandlerService : UserCommandHandlerServiceBase
             await _userCommandHandlerService.HandleCommandAsync(ExitRapidTravelCommand.Instance);
         }
 
-        _appState.SetSelectedTab(tabViewModel!);
+        await _appState.SetSelectedTabAsync(tabViewModel!);
     }
 
     private Task CloseTab()

src/AppCommon/FileTime.App.Core/ViewModels/AppStateBase.cs

@@ -15,17 +15,16 @@ namespace FileTime.App.Core.ViewModels;
 public abstract partial class AppStateBase : IAppState
 {
     private readonly BehaviorSubject<string?> _searchText = new(null);
-    private readonly BehaviorSubject<ITabViewModel?> _selectedTab = new(null);
+    private readonly DeclarativeProperty<ITabViewModel?> _selectedTab = new();
     private readonly DeclarativeProperty<ViewMode> _viewMode = new(Models.Enums.ViewMode.Default);
-    private readonly SourceList<ITabViewModel> _tabs = new();
+    private readonly ObservableCollection<ITabViewModel> _tabs = new();
 
     public IDeclarativeProperty<ViewMode> ViewMode { get; private set; }
 
     public ReadOnlyObservableCollection<ITabViewModel> Tabs { get; private set; }
     public IObservable<string?> SearchText { get; private set; }
 
-    public IObservable<ITabViewModel?> SelectedTab { get; private set; }
-    public ITabViewModel? CurrentSelectedTab { get; private set; }
+    public IDeclarativeProperty<ITabViewModel?> SelectedTab { get; private set; }
     public DeclarativeProperty<string?> RapidTravelText { get; private set; }
 
     partial void OnInitialize()
@@ -33,37 +32,28 @@ public abstract partial class AppStateBase : IAppState
         RapidTravelText = new("");
         ViewMode = _viewMode;
 
-        var tabsObservable = _tabs.Connect();
-
         SearchText = _searchText.AsObservable();
-        SelectedTab = Observable.CombineLatest(tabsObservable.ToCollection(), _selectedTab.DistinctUntilChanged(), GetSelectedTab);
+        SelectedTab = DeclarativePropertyHelpers.CombineLatest<ObservableCollection<ITabViewModel>, ITabViewModel, ITabViewModel>(
+            _tabs.Watch(),
+            _selectedTab,
+            (tabs, selectedTab) => Task.FromResult(GetSelectedTab(tabs, selectedTab))
+        );
 
-        SelectedTab.Subscribe(t =>
-        {
-            _selectedTab.OnNext(t);
-            CurrentSelectedTab = t;
-        });
-
-        tabsObservable
-            .Bind(out var collection)
-            .DisposeMany()
-            .Subscribe();
-
-        Tabs = collection;
+        Tabs = new ReadOnlyObservableCollection<ITabViewModel>(_tabs);
     }
 
     public void AddTab(ITabViewModel tabViewModel)
     {
-        if (_tabs.Items.Any(t => t.TabNumber == tabViewModel.TabNumber))
+        if (_tabs.Any(t => t.TabNumber == tabViewModel.TabNumber))
             throw new ArgumentException($"There is a tab with the same tab number {tabViewModel.TabNumber}.", nameof(tabViewModel));
 
-        var index = _tabs.Items.Count(t => t.TabNumber < tabViewModel.TabNumber);
+        var index = _tabs.Count(t => t.TabNumber < tabViewModel.TabNumber);
         _tabs.Insert(index, tabViewModel);
     }
 
     public void RemoveTab(ITabViewModel tabViewModel)
     {
-        if (!_tabs.Items.Contains(tabViewModel)) return;
+        if (!_tabs.Contains(tabViewModel)) return;
 
         _tabs.Remove(tabViewModel);
     }
@@ -72,7 +62,7 @@ public abstract partial class AppStateBase : IAppState
 
     public async Task SwitchViewModeAsync(ViewMode newViewMode) => await _viewMode.SetValue(newViewMode);
 
-    public void SetSelectedTab(ITabViewModel tabToSelect) => _selectedTab.OnNext(tabToSelect);
+    public async Task SetSelectedTabAsync(ITabViewModel tabToSelect) => await _selectedTab.SetValue(tabToSelect);
 
     private ITabViewModel? GetSelectedTab(IEnumerable<ITabViewModel> tabs, ITabViewModel? expectedSelectedTab)
     {

src/AppCommon/FileTime.App.Core/ViewModels/ItemViewModel.cs

@@ -56,7 +56,7 @@ public abstract partial class ItemViewModel : IItemViewModel
         {
             ItemViewModelType.Main => _appState.RapidTravelText.Map(async (s, _) =>
                 _appState.ViewMode.Value != Models.Enums.ViewMode.RapidTravel 
-                && _appState.CurrentSelectedTab?.CurrentLocation.Value?.Provider is IItemNameConverterProvider nameConverterProvider
+                && _appState.SelectedTab.Value?.CurrentLocation.Value?.Provider is IItemNameConverterProvider nameConverterProvider
                     ? (IReadOnlyList<ItemNamePart>) await nameConverterProvider.GetItemNamePartsAsync(item)
                     : _itemNameConverterService.GetDisplayName(item.DisplayName, s)
             ),

src/Library/DeclarativeProperty/CollectionRepeaterProperty.cs

@@ -7,16 +7,25 @@ public class CollectionRepeaterProperty<TCollection, TItem> : DeclarativePropert
 {
     private TCollection? _currentCollection;
 
-    public CollectionRepeaterProperty(IDeclarativeProperty<TCollection?> from)
+    public CollectionRepeaterProperty(IDeclarativeProperty<TCollection?> from) : base(from.Value)
     {
         _currentCollection = from.Value;
         if (from.Value is { } value)
         {
             value.CollectionChanged += HandleCollectionChanged;
         }
+
         AddDisposable(from.Subscribe(Handle));
     }
 
+    public CollectionRepeaterProperty(TCollection? collection) : base(collection)
+    {
+        ArgumentNullException.ThrowIfNull(collection);
+
+        _currentCollection = collection;
+        collection.CollectionChanged += HandleCollectionChanged;
+    }
+
     private void HandleCollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
     {
         var t = Task.Run(async () => await NotifySubscribersAsync(Value));
@@ -29,7 +38,8 @@ public class CollectionRepeaterProperty<TCollection, TItem> : DeclarativePropert
         {
             currentCollection.CollectionChanged -= HandleCollectionChanged;
         }
-        if (collection is {} newCollection)
+
+        if (collection is { } newCollection)
         {
             newCollection.CollectionChanged -= HandleCollectionChanged;
             newCollection.CollectionChanged += HandleCollectionChanged;

src/Library/DeclarativeProperty/DeclarativePropertyExtensions.cs

@@ -69,6 +69,19 @@ public static class DeclarativePropertyExtensions
         this IDeclarativeProperty<TCollection?> collection)
         where TCollection : IList<TItem>, INotifyCollectionChanged
         => new CollectionRepeaterProperty<TCollection?, TItem>(collection);
+
+    public static IDeclarativeProperty<TCollection?> Watch<TCollection, TItem>(
+        this TCollection collection)
+        where TCollection : IList<TItem>, INotifyCollectionChanged
+        => new CollectionRepeaterProperty<TCollection?, TItem>(collection);
+
+    public static IDeclarativeProperty<ObservableCollection<TItem>?> Watch<TItem>(
+        this ObservableCollection<TItem> collection)
+        => new CollectionRepeaterProperty<ObservableCollection<TItem>?, TItem>(collection);
+
+    public static IDeclarativeProperty<ReadOnlyObservableCollection<TItem>?> Watch<TItem>(
+        this ReadOnlyObservableCollection<TItem> collection)
+        => new CollectionRepeaterProperty<ReadOnlyObservableCollection<TItem>?, TItem>(collection);
     
     
     public static IDeclarativeProperty<TResult?> CombineLatest<T1, T2, TResult>(