初始版本

TodoList/Views/MainWindow.xaml.cs

@@ -19,6 +19,25 @@ namespace TodoList.Views
             // Verify if app shuts down? No, ShutdownMode is Explicit.
         }
 
+        private void Window_PreviewKeyDown(object sender, System.Windows.Input.KeyEventArgs e)
+        {
+            if (e.Key == Key.Escape)
+            {
+                // If settings are open, close settings? 
+                // But user requirement is "Equals pressing X button", which usually means Close/Hide window.
+                // However, if we want better UX:
+                if (DataContext is MainViewModel vm && vm.IsSettingsOpen)
+                {
+                    vm.IsSettingsOpen = false;
+                    e.Handled = true;
+                    return;
+                }
+
+                // Default behavior: Close (Hide) Window
+                Close();
+            }
+        }
+
         private void ShortcutBox_PreviewKeyDown(object sender, System.Windows.Input.KeyEventArgs e)
         {
             e.Handled = true;