Improve WatchProperty

Author: Tyrrrz

YoutubeDownloader/App.axaml.cs

@@ -60,11 +60,9 @@ public App()
                 .GetRequiredService<SettingsService>()
                 .WatchProperty(
                     o => o.Theme,
-                    () =>
+                    theme =>
                     {
-                        RequestedThemeVariant = _services
-                            .GetRequiredService<SettingsService>()
-                            .Theme switch
+                        RequestedThemeVariant = theme switch
                         {
                             ThemeVariant.Light => Avalonia.Styling.ThemeVariant.Light,
                             ThemeVariant.Dark => Avalonia.Styling.ThemeVariant.Dark,

YoutubeDownloader/Localization/LocalizationManager.cs

@@ -14,18 +14,12 @@ public partial class LocalizationManager : ObservableObject, IDisposable
 
     public LocalizationManager(SettingsService settingsService)
     {
-        _eventRoot.Add(
-            settingsService.WatchProperty(
-                o => o.Language,
-                () => Language = settingsService.Language,
-                true
-            )
-        );
+        _eventRoot.Add(settingsService.WatchProperty(o => o.Language, v => Language = v, true));
 
         _eventRoot.Add(
             this.WatchProperty(
                 o => o.Language,
-                () =>
+                _ =>
                 {
                     foreach (var propertyName in EnglishLocalization.Keys)
                         OnPropertyChanged(propertyName);

YoutubeDownloader/Utils/Extensions/NotifyPropertyChangedExtensions.cs

@@ -12,29 +12,31 @@ internal static class NotifyPropertyChangedExtensions
     {
         public IDisposable WatchProperty<TProperty>(
             Expression<Func<TOwner, TProperty>> propertyExpression,
-            Action callback,
+            Action<TProperty> callback,
             bool watchInitialValue = false
         )
         {
             var memberExpression = propertyExpression.Body as MemberExpression;
             if (memberExpression?.Member is not PropertyInfo property)
                 throw new ArgumentException("Provided expression must reference a property.");
 
+            var getValue = propertyExpression.Compile();
+
             void OnPropertyChanged(object? sender, PropertyChangedEventArgs args)
             {
                 if (
                     string.IsNullOrWhiteSpace(args.PropertyName)
                     || string.Equals(args.PropertyName, property.Name, StringComparison.Ordinal)
                 )
                 {
-                    callback();
+                    callback(getValue(owner));
                 }
             }
 
             owner.PropertyChanged += OnPropertyChanged;
 
             if (watchInitialValue)
-                callback();
+                callback(getValue(owner));
 
             return Disposable.Create(() => owner.PropertyChanged -= OnPropertyChanged);
         }

YoutubeDownloader/ViewModels/Components/DashboardViewModel.cs

@@ -53,15 +53,15 @@ SettingsService settingsService
         _eventRoot.Add(
             _settingsService.WatchProperty(
                 o => o.ParallelLimit,
-                () => _downloadSemaphore.MaxCount = _settingsService.ParallelLimit,
+                v => _downloadSemaphore.MaxCount = v,
                 true
             )
         );
 
         _eventRoot.Add(
             Progress.WatchProperty(
                 o => o.Current,
-                () => OnPropertyChanged(nameof(IsProgressIndeterminate))
+                _ => OnPropertyChanged(nameof(IsProgressIndeterminate))
             )
         );
     }

YoutubeDownloader/ViewModels/Components/DownloadViewModel.cs

@@ -39,7 +39,7 @@ LocalizationManager localizationManager
         _eventRoot.Add(
             Progress.WatchProperty(
                 o => o.Current,
-                () => OnPropertyChanged(nameof(IsProgressIndeterminate))
+                _ => OnPropertyChanged(nameof(IsProgressIndeterminate))
             )
         );
     }

YoutubeDownloader/ViewModels/Dialogs/AuthSetupViewModel.cs

@@ -26,7 +26,7 @@ SettingsService settingsService
         _eventRoot.Add(
             _settingsService.WatchProperty(
                 o => o.LastAuthCookies,
-                () =>
+                _ =>
                 {
                     OnPropertyChanged(nameof(Cookies));
                     OnPropertyChanged(nameof(IsAuthenticated));