(MahAppsGH-4012) Register FlipView ListBox index SelectionChanged eve…

…nt only once
batzen · Mar 3, 2021 · 533eb5f · 533eb5f
1 parent 8682b5d
commit 533eb5f
Showing 1 changed file with 19 additions and 9 deletions.
diff --git a/src/MahApps.Metro/Controls/FlipView.cs b/src/MahApps.Metro/Controls/FlipView.cs
@@ -705,6 +705,7 @@ public string ButtonDownContentStringFormat
         private bool allowSelectedIndexChangedCallback = true;
         private Grid bannerGrid;
         private Label bannerLabel;
+        private ListBox indexListBox;
         private Button backButton;
         private Button forwardButton;
         private Button downButton;
@@ -861,6 +862,11 @@ public override void OnApplyTemplate()
 
             this.presenter = this.GetTemplateChild(PART_Presenter) as TransitioningContentControl;
 
+            if (this.indexListBox != null)
+            {
+                this.indexListBox.SelectionChanged -= OnIndexListBoxSelectionChanged;
+            }
+
             if (this.forwardButton != null)
             {
                 this.forwardButton.Click -= this.NextButtonClick;
@@ -881,6 +887,8 @@ public override void OnApplyTemplate()
                 this.downButton.Click -= this.NextButtonClick;
             }
 
+            this.indexListBox = this.GetTemplateChild(PART_Index) as ListBox;
+
             this.forwardButton = this.GetTemplateChild(PART_ForwardButton) as Button;
             this.backButton = this.GetTemplateChild(PART_BackButton) as Button;
             this.upButton = this.GetTemplateChild(PART_UpButton) as Button;
@@ -913,22 +921,24 @@ public override void OnApplyTemplate()
             {
                 this.bannerLabel.Opacity = this.IsBannerEnabled ? 1d : 0d;
             }
-            
+
             this.ExecuteWhenLoaded(() =>
                 {
-                    if (this.GetTemplateChild(PART_Index) is ListBox listBox)
+                    if (this.indexListBox != null)
                     {
-                        listBox.SelectionChanged += (sender, e) =>
-                            {
-                                if (ReferenceEquals(e.OriginalSource, listBox))
-                                {
-                                    e.Handled = true;
-                                }
-                            };
+                        this.indexListBox.SelectionChanged += OnIndexListBoxSelectionChanged;
                     }
                 });
         }
 
+        private void OnIndexListBoxSelectionChanged(object sender, SelectionChangedEventArgs e)
+        {
+            if (ReferenceEquals(e.OriginalSource, this.indexListBox))
+            {
+                e.Handled = true;
+            }
+        }
+
         protected override DependencyObject GetContainerForItemOverride()
         {
             return new FlipViewItem() { HorizontalAlignment = HorizontalAlignment.Stretch };