[Bug fix] Fixed a bug where MarkdownTextBlock loses all events after re-load

[Bug fix] Fixed a bug where MarkdownTextBlock loses all events after re-load. Issue is described here: 0x7c13/Notepads#377

Author: 0x7c13

Microsoft.Toolkit.Uwp.UI.Controls/MarkdownTextBlock/MarkdownTextBlock.Methods.cs

@@ -48,6 +48,9 @@ private void RenderMarkdown()
             // Disconnect from OnClick handlers.
             UnhookListeners();
 
+            // Clear everything that exists.
+            _listeningHyperlinks.Clear();
+
             var markdownRenderedArgs = new MarkdownRenderedEventArgs(null);
 
             // Make sure we have something to parse.
@@ -174,9 +177,25 @@ private void RenderMarkdown()
             MarkdownRendered?.Invoke(this, markdownRenderedArgs);
         }
 
+        private void HookListeners()
+        {
+            // Re-hook all hyper link events we currently have
+            foreach (object link in _listeningHyperlinks)
+            {
+                if (link is Hyperlink hyperlink)
+                {
+                    hyperlink.Click += Hyperlink_Click;
+                }
+                else if (link is Image image)
+                {
+                    image.Tapped += NewImagelink_Tapped;
+                }
+            }
+        }
+
         private void UnhookListeners()
         {
-            // Clear any hyper link events if we have any
+            // Unhook any hyper link events if we have any
             foreach (object link in _listeningHyperlinks)
             {
                 if (link is Hyperlink hyperlink)
@@ -188,9 +207,6 @@ private void UnhookListeners()
                     image.Tapped -= NewImagelink_Tapped;
                 }
             }
-
-            // Clear everything that exists.
-            _listeningHyperlinks.Clear();
         }
 
         /// <summary>

Microsoft.Toolkit.Uwp.UI.Controls/MarkdownTextBlock/MarkdownTextBlock.cs

@@ -47,6 +47,7 @@ private void ThemeListener_ThemeChanged(Helpers.ThemeListener sender)
         private void OnLoaded(object sender, RoutedEventArgs e)
         {
             RegisterThemeChangedHandler();
+            HookListeners();
 
             // Register for property callbacks that are owned by our parent class.
             _fontSizePropertyToken = RegisterPropertyChangedCallback(FontSizeProperty, OnPropertyChanged);