From 74bdc8afbdf277b0e29803e27a83970ea856bf40 Mon Sep 17 00:00:00 2001
From: Dinesh Solanki <15937452+DineshSolanki@users.noreply.github.com>
Date: Thu, 18 Jun 2026 00:49:25 +0530
Subject: [PATCH] fix: prevent TypeInitializationException crash in Window
 static constructor

The Window static constructor loaded a 14K-line ResourceDictionary (Theme.xaml)
via GetResourceInternal, which could throw ArgumentOutOfRangeException from
WPF internals when Application.Current was null or resources were not fully
initialized. Once the static constructor failed, .NET cached the
TypeInitializationException permanently, making all subsequent Window/MessageBox
instantiations crash for the lifetime of the AppDomain.

Changes:
- ResourceHelper: use Lazy<ResourceDictionary> for thread-safe theme
  initialization; add Application.Current.TryFindResource fallback in
  GetResourceInternal when theme dictionary lookup fails or is null
- Window: wrap static constructor in try-catch so a resource loading failure
  falls back to a null style instead of poisoning the type permanently

Fixes #442
---
 .../HandyControl_Shared/Controls/Window/Window.cs    |  9 ++++++++-
 .../Tools/Helper/ResourceHelper.cs                   | 12 ++++++++++--
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/Shared/HandyControl_Shared/Controls/Window/Window.cs b/src/Shared/HandyControl_Shared/Controls/Window/Window.cs
index 7de0ebbe2..76e617d56 100644
--- a/src/Shared/HandyControl_Shared/Controls/Window/Window.cs
+++ b/src/Shared/HandyControl_Shared/Controls/Window/Window.cs
@@ -49,7 +49,14 @@ public class Window : System.Windows.Window
 
         static Window()
         {
-            StyleProperty.OverrideMetadata(typeof(Window), new FrameworkPropertyMetadata(ResourceHelper.GetResourceInternal<Style>(ResourceToken.WindowWin10)));
+            try
+            {
+                StyleProperty.OverrideMetadata(typeof(Window), new FrameworkPropertyMetadata(ResourceHelper.GetResourceInternal<Style>(ResourceToken.WindowWin10)));
+            }
+            catch
+            {
+                StyleProperty.OverrideMetadata(typeof(Window), new FrameworkPropertyMetadata(null));
+            }
         }
 
         public Window()
diff --git a/src/Shared/HandyControl_Shared/Tools/Helper/ResourceHelper.cs b/src/Shared/HandyControl_Shared/Tools/Helper/ResourceHelper.cs
index 90b59ecea..0706ad1c9 100644
--- a/src/Shared/HandyControl_Shared/Tools/Helper/ResourceHelper.cs
+++ b/src/Shared/HandyControl_Shared/Tools/Helper/ResourceHelper.cs
@@ -10,6 +10,8 @@ namespace HandyControl.Tools;
 /// </summary>
 public class ResourceHelper
 {
+    private static readonly Lazy<ResourceDictionary> _themeLazy = new(GetStandaloneTheme);
+
     private static ResourceDictionary _theme;
 
     /// <summary>
@@ -29,11 +31,17 @@ public static T GetResource<T>(string key)
 
     internal static T GetResourceInternal<T>(string key)
     {
-        if (GetTheme()[key] is T resource)
+        var theme = GetTheme();
+        if (theme != null && theme[key] is T resource)
         {
             return resource;
         }
 
+        if (Application.Current != null && Application.Current.TryFindResource(key) is T appResource)
+        {
+            return appResource;
+        }
+
         return default;
     }
 
@@ -72,7 +80,7 @@ public static ResourceDictionary GetSkin(Assembly assembly, string themePath, Sk
     /// <summary>
     ///     get HandyControl theme
     /// </summary>
-    public static ResourceDictionary GetTheme() => _theme ??= GetStandaloneTheme();
+    public static ResourceDictionary GetTheme() => _theme ??= _themeLazy.Value;
 
     public static ResourceDictionary GetStandaloneTheme()
     {