Add ActualApplicationThemeChanged in MainViewModel

Author: Jack251970

Flow.Launcher.Plugin/EventHandler.cs

@@ -39,7 +39,14 @@ namespace Flow.Launcher.Plugin
     /// <param name="sender"></param>
     /// <param name="args"></param>
     public delegate void VisibilityChangedEventHandler(object sender, VisibilityChangedEventArgs args);
-    
+
+    /// <summary>
+    /// A delegate for when the actual application theme is changed
+    /// </summary>
+    /// <param name="sender"></param>
+    /// <param name="args"></param>
+    public delegate void ActualApplicationThemeChangedEventHandler(object sender, ActualApplicationThemeChangedEventArgs args);
+
     /// <summary>
     /// The event args for <see cref="VisibilityChangedEventHandler"/>
     /// </summary>
@@ -77,4 +84,15 @@ public class FlowLauncherQueryEventArgs
         /// </summary>
         public Query Query { get; set; }
     }
+
+    /// <summary>
+    /// The event args for <see cref="ActualApplicationThemeChangedEventHandler"/>
+    /// </summary>
+    public class ActualApplicationThemeChangedEventArgs : EventArgs
+    {
+        /// <summary>
+        /// <see langword="true"/> if the application has changed actual theme
+        /// </summary>
+        public bool IsDark { get; init; }
+    }
 }

Flow.Launcher/ViewModel/MainViewModel.cs

@@ -22,6 +22,7 @@
 using Flow.Launcher.Plugin.SharedCommands;
 using Flow.Launcher.Storage;
 using Microsoft.VisualStudio.Threading;
+using ModernWpf;
 
 namespace Flow.Launcher.ViewModel
 {
@@ -195,6 +196,18 @@ public MainViewModel()
 
             RegisterViewUpdate();
             _ = RegisterClockAndDateUpdateAsync();
+
+            ThemeManager.Current.ActualApplicationThemeChanged += ThemeManager_ActualApplicationThemeChanged;
+        }
+
+        private void ThemeManager_ActualApplicationThemeChanged(ThemeManager sender, object args)
+        {
+            ActualApplicationThemeChanged?.Invoke(
+                Application.Current,
+                new ActualApplicationThemeChangedEventArgs()
+                {
+                    IsDark = sender.ActualApplicationTheme == ApplicationTheme.Dark
+                });
         }
 
         private void RegisterViewUpdate()
@@ -821,6 +834,7 @@ private ResultsViewModel SelectedResults
         public bool MainWindowVisibilityStatus { get; set; } = true;
 
         public event VisibilityChangedEventHandler VisibilityChanged;
+        public event ActualApplicationThemeChangedEventHandler ActualApplicationThemeChanged;
 
         public Visibility ClockPanelVisibility { get; set; }
         public Visibility SearchIconVisibility { get; set; }
@@ -1975,6 +1989,7 @@ protected virtual void Dispose(bool disposing)
                     {
                         _resultsViewUpdateTask.Dispose();
                     }
+                    ThemeManager.Current.ActualApplicationThemeChanged -= ThemeManager_ActualApplicationThemeChanged;
                     _disposed = true;
                 }
             }