added unsubscribe in OnDetaching

microsoft · Dec 12, 2019 · 9da69d6 · 9da69d6
1 parent f828660
commit 9da69d6
Showing 1 changed file with 25 additions and 12 deletions.
diff --git a/src/Microsoft.Xaml.Behaviors/Core/DataTrigger.cs b/src/Microsoft.Xaml.Behaviors/Core/DataTrigger.cs
@@ -47,22 +47,35 @@ protected override void OnAttached()
             //fixes issue #11. We want to evaluate the binding's initial value when the element is first loaded
             if (AssociatedObject is FrameworkElement element)
             {
-                void OnElementLoaded(object sender, RoutedEventArgs e)
-                {
-                    try
-                    {
-                        this.EvaluateBindingChange(e);
-                    }
-                    finally
-                    {
-                        element.Loaded -= OnElementLoaded;
-                    }                    
-                }
-
                 element.Loaded += OnElementLoaded;
             }
         }
 
+        protected override void OnDetaching()
+        {
+            base.OnDetaching();
+            UnsubscribeElementLoadedEvent();
+        }
+
+        private void OnElementLoaded(object sender, RoutedEventArgs e)
+        {
+            try
+            {
+                EvaluateBindingChange(e);
+            } finally
+            {
+                UnsubscribeElementLoadedEvent();
+            }
+        }
+
+        private void UnsubscribeElementLoadedEvent()
+        {
+            if (AssociatedObject is FrameworkElement element)
+            {
+                element.Loaded -= OnElementLoaded;
+            }
+        }
+
         /// <summary>
         /// Called when the binding property has changed. 
         /// UA_REVIEW:chabiss