From 295f4cf9a28c83385b8b6c9a332246c67729d016 Mon Sep 17 00:00:00 2001
From: tyrrrz <1935960+Tyrrrz@users.noreply.github.com>
Date: Fri, 3 Apr 2026 00:13:40 +0300
Subject: [PATCH] Improve `WatchProperty`

---
 DiscordChatExporter.Gui/App.axaml.cs                   |  6 ++----
 .../Localization/LocalizationManager.cs                | 10 ++--------
 .../Extensions/NotifyPropertyChangedExtensions.cs      |  8 +++++---
 .../ViewModels/Components/DashboardViewModel.cs        |  4 ++--
 4 files changed, 11 insertions(+), 17 deletions(-)

diff --git a/DiscordChatExporter.Gui/App.axaml.cs b/DiscordChatExporter.Gui/App.axaml.cs
index f695c404..b4f624d3 100644
--- a/DiscordChatExporter.Gui/App.axaml.cs
+++ b/DiscordChatExporter.Gui/App.axaml.cs
@@ -56,11 +56,9 @@ public class App : Application, IDisposable
                 .GetRequiredService<SettingsService>()
                 .WatchProperty(
                     o => o.Theme,
-                    () =>
+                    v =>
                     {
-                        RequestedThemeVariant = _services
-                            .GetRequiredService<SettingsService>()
-                            .Theme switch
+                        RequestedThemeVariant = v switch
                         {
                             ThemeVariant.Light => Avalonia.Styling.ThemeVariant.Light,
                             ThemeVariant.Dark => Avalonia.Styling.ThemeVariant.Dark,
diff --git a/DiscordChatExporter.Gui/Localization/LocalizationManager.cs b/DiscordChatExporter.Gui/Localization/LocalizationManager.cs
index 71974f21..de917565 100644
--- a/DiscordChatExporter.Gui/Localization/LocalizationManager.cs
+++ b/DiscordChatExporter.Gui/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);
diff --git a/DiscordChatExporter.Gui/Utils/Extensions/NotifyPropertyChangedExtensions.cs b/DiscordChatExporter.Gui/Utils/Extensions/NotifyPropertyChangedExtensions.cs
index 027bccef..eef1583f 100644
--- a/DiscordChatExporter.Gui/Utils/Extensions/NotifyPropertyChangedExtensions.cs
+++ b/DiscordChatExporter.Gui/Utils/Extensions/NotifyPropertyChangedExtensions.cs
@@ -12,7 +12,7 @@ internal static class NotifyPropertyChangedExtensions
     {
         public IDisposable WatchProperty<TProperty>(
             Expression<Func<TOwner, TProperty>> propertyExpression,
-            Action callback,
+            Action<TProperty> callback,
             bool watchInitialValue = false
         )
         {
@@ -20,6 +20,8 @@ internal static class NotifyPropertyChangedExtensions
             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 (
@@ -27,14 +29,14 @@ internal static class NotifyPropertyChangedExtensions
                     || 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);
         }
diff --git a/DiscordChatExporter.Gui/ViewModels/Components/DashboardViewModel.cs b/DiscordChatExporter.Gui/ViewModels/Components/DashboardViewModel.cs
index ad6411ae..dd7a8454 100644
--- a/DiscordChatExporter.Gui/ViewModels/Components/DashboardViewModel.cs
+++ b/DiscordChatExporter.Gui/ViewModels/Components/DashboardViewModel.cs
@@ -53,14 +53,14 @@ public partial class DashboardViewModel : ViewModelBase
         _eventRoot.Add(
             Progress.WatchProperty(
                 o => o.Current,
-                () => OnPropertyChanged(nameof(IsProgressIndeterminate))
+                _ => OnPropertyChanged(nameof(IsProgressIndeterminate))
             )
         );
 
         _eventRoot.Add(
             SelectedChannels.WatchProperty(
                 o => o.Count,
-                () => ExportCommand.NotifyCanExecuteChanged()
+                _ => ExportCommand.NotifyCanExecuteChanged()
             )
         );
     }