Fix crash when Visibility is changed to Collapsed on a view. (microsoft#1840)

zholobov · reseul · commit 0a2dff3c939c · 2018-05-18T15:33:46.000-07:00
diff --git a/ReactWindows/ReactNative/Accessibility/AccessibilityHelper.cs b/ReactWindows/ReactNative/Accessibility/AccessibilityHelper.cs
@@ -156,19 +156,14 @@ private static bool GetDirty(UIElement element)
             return EnsureElementAccessibilityContext(element).Dirty;
         }
 
-        private static void MarkElementDirty(UIElement element, bool skipIfNoPeer = false)
+        private static void MarkElementDirty(UIElement element)
         {
             // Retrieve automation peer
             var peer = FrameworkElementAutomationPeer.FromElement(element);
 
             if (peer == null)
             {
-                if (skipIfNoPeer)
-                {
-                    return;
-                }
-
-                throw new InvalidOperationException("Element has no automation peer");
+                return;
             }
 
 #if PERF_LOG
@@ -224,7 +219,7 @@ public static void OnChildAdded(UIElement parent, DependencyObject child)
             SetCurrentlyHidingChildren(parent, ElementAccessibilityContext.HidingChildren.NotSure);
 
             // Mark the parent dirty (or skip if there is no associated peer available)
-            MarkElementDirty(parent, true);
+            MarkElementDirty(parent);
         }
 
         /// <summary>
@@ -238,16 +233,41 @@ public static void OnChildRemoved(UIElement parent)
             parent.UpdateLayout();
 
             // Mark the parent dirty (or skip if there is no associated peer available)
-            MarkElementDirty(parent, true);
+            MarkElementDirty(parent);
         }
 
         /// <summary>
         /// Marks accessibility data in UI tree for update after a relevant (to accessibility) property of that element changed.
         /// For example, it is used by <see cref="RichTextBlock"/> to notify when text or structure is changed inside the text block.
         /// </summary>
         /// <param name="uiElement">The <see cref="UIElement"/>.</param>
-        public static void OnElementChanged(UIElement uiElement)
+        /// <param name="dependencyProperty">The dependency property that changed. It's important to provide this parameter if possible.</param>
+        public static void OnElementChanged(UIElement uiElement, DependencyProperty dependencyProperty = null)
         {
+            if (ReferenceEquals(UIElement.VisibilityProperty, dependencyProperty))
+            {
+                // add/remove like
+                var fe = uiElement as FrameworkElement;
+                if (fe == null)
+                {
+                    return;
+                }
+                var parent = fe.Parent as UIElement;
+                if (parent == null)
+                {
+                    return;
+                }
+
+                if (uiElement.Visibility == Visibility.Visible)
+                {
+                    OnChildAdded(parent, fe);
+                }
+                else
+                {
+                    OnChildRemoved(parent);
+                }
+                return;
+            }
             // Mark the element dirty
             MarkElementDirty(uiElement);
         }
diff --git a/ReactWindows/ReactNative/UIManager/BaseViewManager.cs b/ReactWindows/ReactNative/UIManager/BaseViewManager.cs
@@ -124,6 +124,7 @@ public void SetZIndex(TFrameworkElement view, int zIndex)
         public void SetDisplay(TFrameworkElement view, string display)
         {
             view.Visibility = display == "none" ? Visibility.Collapsed : Visibility.Visible;
+            AccessibilityHelper.OnElementChanged(view, UIElement.VisibilityProperty);
         }
 
         /// <summary>

Original file line number	Diff line number	Diff line change
`@@ -124,6 +124,7 @@ public void SetZIndex(TFrameworkElement view, int zIndex)`
`124`	`124`	`public void SetDisplay(TFrameworkElement view, string display)`
`125`	`125`	`{`
`126`	`126`	`view.Visibility = display == "none" ? Visibility.Collapsed : Visibility.Visible;`
	`127`	`+ AccessibilityHelper.OnElementChanged(view, UIElement.VisibilityProperty);`
`127`	`128`	`}`
`128`	`129`
`129`	`130`	`/// <summary>`