diff --git a/MapControl/WPF/DependencyPropertyHelper.WPF.cs b/MapControl/WPF/DependencyPropertyHelper.WPF.cs
index 00a7a444..16007b0d 100644
--- a/MapControl/WPF/DependencyPropertyHelper.WPF.cs
+++ b/MapControl/WPF/DependencyPropertyHelper.WPF.cs
@@ -71,7 +71,13 @@ namespace MapControl
 
             if (changed != null)
             {
-                metadata.PropertyChangedCallback = (o, e) => changed((FrameworkElement)o, (TValue)e.OldValue, (TValue)e.NewValue);
+                metadata.PropertyChangedCallback = (o, e) =>
+                {
+                    if (o is FrameworkElement element)
+                    {
+                        changed(element, (TValue)e.OldValue, (TValue)e.NewValue);
+                    }
+                };
             }
 
             return DependencyProperty.RegisterAttached(name, typeof(TValue), typeof(TOwner), metadata);
diff --git a/MapControl/WinUI/DependencyPropertyHelper.WinUI.cs b/MapControl/WinUI/DependencyPropertyHelper.WinUI.cs
index 469b2056..486de731 100644
--- a/MapControl/WinUI/DependencyPropertyHelper.WinUI.cs
+++ b/MapControl/WinUI/DependencyPropertyHelper.WinUI.cs
@@ -34,9 +34,15 @@ namespace MapControl
             Action<FrameworkElement, TValue, TValue> changed = null,
             bool inherits = false) // unused in WinUI/UWP
         {
-            var metadata = changed != null
-                ? new PropertyMetadata(defaultValue, (o, e) => changed((FrameworkElement)o, (TValue)e.OldValue, (TValue)e.NewValue))
-                : new PropertyMetadata(defaultValue);
+            var metadata = changed == null
+                ? new PropertyMetadata(defaultValue)
+                : new PropertyMetadata(defaultValue, (o, e) =>
+                {
+                    if (o is FrameworkElement element)
+                    {
+                        changed(element, (TValue)e.OldValue, (TValue)e.NewValue);
+                    }
+                });
 
             return DependencyProperty.RegisterAttached(name, typeof(TValue), typeof(TOwner), metadata);
         }