Merge pull request #4123 from MahApps/fix/4117

punker76 · punker76 · commit 39ba5fa78cd3 · 2021-06-10T16:38:38.000+02:00
Fix getting the wrong Ancestor (ScrollViewer) at CustomValidationPopup
diff --git a/src/MahApps.Metro/Controls/CustomValidationPopup.cs b/src/MahApps.Metro/Controls/CustomValidationPopup.cs
@@ -144,7 +144,7 @@ private void CustomValidationPopup_Loaded(object sender, RoutedEventArgs e)
                 this.scrollViewer.ScrollChanged -= this.ScrollViewer_ScrollChanged;
             }
 
-            this.scrollViewer = adornedElement.TryFindParent<ScrollViewer>();
+            this.scrollViewer = adornedElement.GetVisualAncestor<ScrollViewer>();
             if (this.scrollViewer != null)
             {
                 this.scrollViewer.ScrollChanged += this.ScrollViewer_ScrollChanged;
diff --git a/src/MahApps.Metro/Controls/TreeHelper.cs b/src/MahApps.Metro/Controls/TreeHelper.cs
@@ -58,6 +58,47 @@ public static IEnumerable<DependencyObject> GetAncestors(this DependencyObject c
             }
         }
 
+        /// <summary>
+        /// Returns full visual ancestry, starting at the leaf.
+        /// <para>If element is not of <see cref="Visual"/> or <see cref="Visual3D"/> the logical ancestry is used.</para>
+        /// </summary>
+        /// <param name="leaf">The starting object.</param>
+        /// <returns></returns>
+        public static IEnumerable<DependencyObject> GetVisualAncestry(this DependencyObject? leaf)
+        {
+            while (leaf != null)
+            {
+                yield return leaf;
+                leaf = leaf is Visual || leaf is Visual3D
+                    ? VisualTreeHelper.GetParent(leaf)
+                    : LogicalTreeHelper.GetParent(leaf);
+            }
+        }
+
+        /// <summary>
+        /// Tries to find and returns a visual ancestor, starting at the leaf.
+        /// <para>If element is not of <see cref="Visual"/> or <see cref="Visual3D"/> the logical ancestry is used.</para>
+        /// </summary>
+        /// <param name="leaf">The starting object.</param>
+        /// <returns></returns>
+        public static T GetVisualAncestor<T>(this DependencyObject? leaf)
+            where T : DependencyObject
+        {
+            while (leaf != null)
+            {
+                if (leaf is T ancestor)
+                {
+                    return ancestor;
+                }
+
+                leaf = leaf is Visual || leaf is Visual3D
+                    ? VisualTreeHelper.GetParent(leaf)
+                    : LogicalTreeHelper.GetParent(leaf);
+            }
+
+            return default(T);
+        }
+
         /// <summary>
         /// Finds a Child of a given item in the visual tree. 
         /// </summary>

Original file line number	Diff line number	Diff line change
`@@ -144,7 +144,7 @@ private void CustomValidationPopup_Loaded(object sender, RoutedEventArgs e)`
`144`	`144`	`this.scrollViewer.ScrollChanged -= this.ScrollViewer_ScrollChanged;`
`145`	`145`	`}`
`146`	`146`
`147`		`- this.scrollViewer = adornedElement.TryFindParent<ScrollViewer>();`
	`147`	`+ this.scrollViewer = adornedElement.GetVisualAncestor<ScrollViewer>();`
`148`	`148`	`if (this.scrollViewer != null)`
`149`	`149`	`{`
`150`	`150`	`this.scrollViewer.ScrollChanged += this.ScrollViewer_ScrollChanged;`