修复浅色主题控件不跟随 - ThemeHelper遍历MergedDictionaries + 强制重绘

src/YZWater.Avalonia/App.axaml.cs

@@ -48,5 +48,14 @@ public partial class App : Application
         if (resources.Count == 0 || _darkTheme == null || _lightTheme == null) return;
 
         resources[0] = ThemeService.Instance.IsDarkTheme ? _darkTheme : _lightTheme;
+
+        // 强制所有窗口重绘
+        if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
+        {
+            foreach (var window in desktop.Windows)
+            {
+                window.InvalidateVisual();
+            }
+        }
     }
 }

src/YZWater.Avalonia/Controls/ThemeHelper.cs

@@ -1,5 +1,6 @@
 using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Media;
 
 namespace YZWater.Avalonia.Controls;
@@ -16,14 +17,38 @@ internal static class ThemeHelper
     {
         try
         {
-            var resources = Application.Current?.Resources;
-            if (resources != null && resources.TryGetResource(key, null, out var value) && value is IBrush brush)
-                return brush;
+            // 遍历所有 MergedDictionaries 查找资源
+            var app = Application.Current;
+            if (app?.Resources?.MergedDictionaries != null)
+            {
+                foreach (var dict in app.Resources.MergedDictionaries)
+                {
+                    if (dict.TryGetResource(key, null, out var value) && value is IBrush brush)
+                        return brush;
+                }
+            }
+            // 尝试从根资源查找
+            if (app != null && app.Resources.TryGetResource(key, null, out var rootValue) && rootValue is IBrush rootBrush)
+                return rootBrush;
         }
         catch { }
         return new SolidColorBrush(Color.Parse(fallbackHex));
     }
 
+    /// <summary>
+    /// 通知所有控件重绘（在主题切换后调用）
+    /// </summary>
+    public static void InvalidateAll()
+    {
+        if (Application.Current?.ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
+        {
+            foreach (var window in desktop.Windows)
+            {
+                window.InvalidateVisual();
+            }
+        }
+    }
+
     // 常用快捷方法
     public static IBrush AppBg() => GetBrush("AppBgBrush", "#0A0E14");
     public static IBrush SurfaceBg() => GetBrush("SurfaceBgBrush", "#111820");