WebView2 in ScrollViewer

[andrewdewaal]

   The approach proposed here is probably not going to happen. If WebView2 drew into an enormous surface the width/height of the entire page, that would provide the desired smooth scrolling experience but would have a huge performance cost for that surface. That surface cost could be mitigated if WebView2 drew into a XAML VirtualSurfaceImageSource, which would require significant design changes and other complexities due to the WebView2 Runtime rendering outside of the app process.

Originally posted by @codendone in #5654 (comment)

We are in the process of migrating from WebView to WebView2. Our application allows a user to interact with HTML content (such as highlighting), and allows swiping to the previous or next content. Our implementation for this was, from a high level, a FlipView wherein each FlipViewItem contained a WebView.
Since WebView2 consumes all scroll and pan actions, we have lost our ability to swipe to content unless we disable the webview, in which case the user can't interact with the content.
To confirm your previous statement, there isn't a way presently to use a WebView2 (allowing user interaction) within a ScrollViewer? If that is the case, is there a possibility of adding this functionality?
Thanks very much!

[codendone]

From an underlying implementation perspective, the FlipView scenario is the same as #4596. My comment from that issue applies here as well:

We call this "scroll chaining", where any unusable amount of scrolling will chain up to parent containers. This is something we plan to support, but we don't currently have an ETA for this.

It is still the case that we want to support this eventually and don't currently have an ETA.

[nbevans]

This is quite frustrating that scroll chaining is not supported and neither is any way to disable the capture of the PointerWheelChanged events. Due to the lower level way that WebView2 sets up its event hooks for pointer events, it seems to bypass all the conventional means available to control event routing in UWP apps.

[nbevans]

It seems to be possible to hackily get an acceptable workaround by using a pattern like this:

Essentially it hooks the pointer wheel event, and disables hit testing entirely, then uses a debouncer to re-enable hit testing after 500ms of no further pointer wheel events. This gives the effect that when scrolling your ScrollView, the WebView2 doesn't stop the scrolling. But it still allows for interactivity with the WebView2 e.g. mouse hover/clicks events still work.

        public class SingaporeWebView2Wrapper : X.Controls.UserControl {
            public WebView2 WebView2 { get; }
            public SingaporeWebView2Wrapper(WebView2 webView2) {
                WebView2 = webView2;
                Content = webView2;

                timer = DispatcherQueue.GetForCurrentThread().CreateTimer();
                webView2.PointerWheelChanged += WebView2_PointerWheelChanged;
            }

            private DispatcherQueueTimer timer;

            private void WebView2_PointerWheelChanged(object sender, PointerRoutedEventArgs e) {
                System.Diagnostics.Trace.WriteLine("IsHitTestVisible = " + WebView2.IsHitTestVisible);
                WebView2.IsHitTestVisible = false;
                timer.Debounce(() => {
                    WebView2.IsHitTestVisible = true;
                    System.Diagnostics.Trace.WriteLine("IsHitTestVisible = " + WebView2.IsHitTestVisible);
                }, TimeSpan.FromMilliseconds(500));
            }
        }

[michael-hawker]

Related to #108 I suppose too?

[andrewdewaal]

Received; thanks!

…

On Wed, Jul 12, 2023, 20:33 Michael Hawker MSFT (XAML Llama) < ***@***.***> wrote: Related to #108 <#108> I suppose too? — Reply to this email directly, view it on GitHub <#7902 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABPZ3AR52ULU5NCO3UZXQZ3XP464BANCNFSM6AAAAAAR3QDPYM> . You are receiving this because you authored the thread.Message ID: ***@***.***>