From 0fee13f821e406b808f77b8157a1f4f5c8ee2176 Mon Sep 17 00:00:00 2001
From: Julien Lebosquain <julien@lebosquain.net>
Date: Wed, 4 Feb 2026 03:14:51 +0000
Subject: [PATCH] Add IsAlive property to IRef<T> (#20593)

---
 src/Avalonia.Base/Media/Imaging/Bitmap.cs | 4 +---
 src/Avalonia.Base/Utilities/Ref.cs        | 6 ++++++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/Avalonia.Base/Media/Imaging/Bitmap.cs b/src/Avalonia.Base/Media/Imaging/Bitmap.cs
index 9c0c20d170..63ec02737f 100644
--- a/src/Avalonia.Base/Media/Imaging/Bitmap.cs
+++ b/src/Avalonia.Base/Media/Imaging/Bitmap.cs
@@ -291,9 +291,7 @@ namespace Avalonia.Media.Imaging
         {
             get
             {
-                // TODO12: We should probably make PlatformImpl to be nullable or make it possible to check
-                // and fix IRef<T> in general (right now Item is not nullable while it internally is)
-                if (PlatformImpl.Item == null!)
+                if (!PlatformImpl.IsAlive)
                     return null;
                 return PlatformImpl;
             }
diff --git a/src/Avalonia.Base/Utilities/Ref.cs b/src/Avalonia.Base/Utilities/Ref.cs
index 0b6abe5189..49a7a42710 100644
--- a/src/Avalonia.Base/Utilities/Ref.cs
+++ b/src/Avalonia.Base/Utilities/Ref.cs
@@ -28,6 +28,10 @@ namespace Avalonia.Utilities
         /// <returns>A reference to the value as the new type but sharing the refcount.</returns>
         IRef<TResult> CloneAs<TResult>() where TResult : class;
 
+        /// <summary>
+        /// Gets whether the reference still tracks a valid item.
+        /// </summary>
+        bool IsAlive { get; }
 
         /// <summary>
         /// The current refcount of the object tracked in this reference. For debugging/unit test use only.
@@ -172,6 +176,8 @@ namespace Avalonia.Utilities
                 return new Ref<TResult>(item, counter);
             }
 
+            public bool IsAlive => _item is not null;
+
             public int RefCount => _counter?.RefCount ?? throw new ObjectDisposedException("Ref<" + typeof(T) + ">");
         }
     }