Performance optimization for Windows-XAML#902 issue

Opiumtm · May 3, 2016 · b9734ae · b9734ae
1 parent ef73476
commit b9734ae
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Showing 2 changed files with 59 additions and 2 deletions.
diff --git a/Template10 (Library)/Behaviors/EllipsisBehavior.cs b/Template10 (Library)/Behaviors/EllipsisBehavior.cs
@@ -3,7 +3,10 @@
 using Windows.UI.Xaml.Controls;
 using Template10.Utils;
 using System.Linq;
+using System.Runtime.CompilerServices;
 using Windows.Foundation.Collections;
+using Windows.UI.Xaml.Media;
+using Template10.Controls;
 
 namespace Template10.Behaviors
 {
@@ -46,10 +49,51 @@ public Visibilities Visibility
             DependencyProperty.Register(nameof(Visibility), typeof(Visibilities),
                 typeof(EllipsisBehavior), new PropertyMetadata(Visibilities.Auto));
 
-        private void Update()
+        private Button FindButtonInternal()
+        {
+            return (commandBar as PageHeader)?.GetMoreButton();
+        }
+
+        private Button FindButtonByName()
+        {
+            if (VisualTreeHelper.GetChildrenCount(commandBar) > 0)
+            {
+                var child = VisualTreeHelper.GetChild(commandBar, 0) as FrameworkElement; /* Templated root */
+                return child?.FindName("MoreButton") as Button;
+            }
+            return null;
+        }
+
+        private Button FindButtonByTreeEnum()
         {
             var controls = XamlUtils.AllChildren<Control>(commandBar);
-            var button = controls.OfType<Button>().FirstOrDefault(x => x.Name.Equals("MoreButton"));
+            return controls.OfType<Button>().FirstOrDefault(x => x.Name.Equals("MoreButton"));
+        }
+
+        private Button FindButton()
+        {
+            if (commandBar == null)
+            {
+                return null;
+            }
+            var r = FindButtonInternal(); // try get button from internal cached value
+                                          // most optimized scenario for PageHeader control, no WinRT interop calls
+            if (r != null)
+            {
+                return r;
+            }
+            r = FindButtonByName(); // try find button by name from templated root
+                                    // minimized WinRT interop calls (3 calls) for MUCH better performance
+            if (r != null)
+            {
+                return r;
+            }
+            return FindButtonByTreeEnum(); // fallback method - many WinRT interop calls so it is very expensive
+        }
+
+        private void Update()
+        {
+            var button = FindButton();
             if (button == null)
                 return;
             switch (Visibility)

diff --git a/Template10 (Library)/Controls/PageHeader.cs b/Template10 (Library)/Controls/PageHeader.cs
@@ -114,5 +114,18 @@ public string Text
             {
                 (d as PageHeader).Content = e.NewValue;
             }));
+
+        private Button moreButton;
+
+        protected override void OnApplyTemplate()
+        {
+            base.OnApplyTemplate();
+            moreButton = GetTemplateChild("MoreButton") as Button;
+        }
+
+        internal Button GetMoreButton()
+        {
+            return moreButton;
+        }
     }
 }