From facc253b21a848644b5d0469019803c57ffa3f9e Mon Sep 17 00:00:00 2001
From: Jumar Macato <16554748+jmacato@users.noreply.github.com>
Date: Fri, 3 Jul 2026 03:20:20 +0800
Subject: [PATCH] Convert ExpandCollapseState to its UIA wire value in the
 Win32 automation layer; Avalonia declares PartiallyExpanded and LeafNode in
 the opposite order from UIA. (#21693)

---
 .../AutomationNode.ExpandCollapse.cs              | 15 +++++++++++++--
 .../Avalonia.Win32.Automation/AutomationNode.cs   |  4 ++--
 .../Interop/IExpandCollapseProvider.cs            |  3 +--
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/src/Windows/Avalonia.Win32.Automation/AutomationNode.ExpandCollapse.cs b/src/Windows/Avalonia.Win32.Automation/AutomationNode.ExpandCollapse.cs
index c28d000f56..200d1c93a9 100644
--- a/src/Windows/Avalonia.Win32.Automation/AutomationNode.ExpandCollapse.cs
+++ b/src/Windows/Avalonia.Win32.Automation/AutomationNode.ExpandCollapse.cs
@@ -6,11 +6,22 @@ namespace Avalonia.Win32.Automation
 {
     internal partial class AutomationNode : UIA.IExpandCollapseProvider
     {
-        ExpandCollapseState UIA.IExpandCollapseProvider.GetExpandCollapseState()
+        int UIA.IExpandCollapseProvider.GetExpandCollapseState()
         {
-            return InvokeSync<IExpandCollapseProvider, ExpandCollapseState>(x => x.ExpandCollapseState);
+            return ToUiaExpandCollapseState(InvokeSync<IExpandCollapseProvider, ExpandCollapseState>(x => x.ExpandCollapseState));
         }
 
+        // Avalonia declares PartiallyExpanded and LeafNode in the opposite order
+        // from the UIA wire values.
+        internal static int ToUiaExpandCollapseState(ExpandCollapseState state) => state switch
+        {
+            ExpandCollapseState.Collapsed => 0,
+            ExpandCollapseState.Expanded => 1,
+            ExpandCollapseState.PartiallyExpanded => 2,
+            ExpandCollapseState.LeafNode => 3,
+            _ => 0,
+        };
+
         void UIA.IExpandCollapseProvider.Expand() => InvokeSync<IExpandCollapseProvider>(x => x.Expand());
         void UIA.IExpandCollapseProvider.Collapse() => InvokeSync<IExpandCollapseProvider>(x => x.Collapse());
     }
diff --git a/src/Windows/Avalonia.Win32.Automation/AutomationNode.cs b/src/Windows/Avalonia.Win32.Automation/AutomationNode.cs
index e2ffca2ea7..1c0236e8c0 100644
--- a/src/Windows/Avalonia.Win32.Automation/AutomationNode.cs
+++ b/src/Windows/Avalonia.Win32.Automation/AutomationNode.cs
@@ -301,8 +301,8 @@ namespace Avalonia.Win32.Automation
                 UiaCoreProviderApi.UiaRaiseAutomationPropertyChangedEvent(
                     this,
                     (int)id,
-                    e.OldValue as IConvertible,
-                    e.NewValue as IConvertible);
+                    e.OldValue is ExpandCollapseState o ? ToUiaExpandCollapseState(o) : e.OldValue as IConvertible,
+                    e.NewValue is ExpandCollapseState n ? ToUiaExpandCollapseState(n) : e.NewValue as IConvertible);
             }
 
             if (id == UiaPropertyId.Name && Peer.GetLiveSetting() != AutomationLiveSetting.Off)
diff --git a/src/Windows/Avalonia.Win32.Automation/Interop/IExpandCollapseProvider.cs b/src/Windows/Avalonia.Win32.Automation/Interop/IExpandCollapseProvider.cs
index 7e5cc048de..2621edf28e 100644
--- a/src/Windows/Avalonia.Win32.Automation/Interop/IExpandCollapseProvider.cs
+++ b/src/Windows/Avalonia.Win32.Automation/Interop/IExpandCollapseProvider.cs
@@ -1,6 +1,5 @@
 using System.Runtime.InteropServices;
 using System.Runtime.InteropServices.Marshalling;
-using Avalonia.Automation;
 
 namespace Avalonia.Win32.Automation.Interop;
 
@@ -10,5 +9,5 @@ internal partial interface IExpandCollapseProvider
 {
     void Expand();
     void Collapse();
-    ExpandCollapseState GetExpandCollapseState();
+    int GetExpandCollapseState();
 }