Windows Phone 7 WebBrowser control swallows manipulation events?

Question

If I place a WebBrowser control on any page, the page no longer responds to manipulation events under the WebBrowser. Other areas of the page work fine.

It's easily confirmed by overriding OnManipulationCompleted in a page, then placing a WebBrowser control on the page. Try swiping over the WebBrowser, and OnManipulationCompleted is never called.

I can't set the WebBrowser to IsHitTestVisible=false because I need to be able to click on links. But I want the page to respond to left/right swipes.

Anyone got any bright ideas? Or know if this is a bug in the current release?

Answer 1

I'd like to extend what Skeet already written.

The point is, that the MS WP7 dev team has published "guidelines", where they highly discourage putting (on the same page) multiple layout controls that accept and react to the same set of gestures. For example, you shouldn't try to embed a Pivot inside a Pano, because the horizontal-swipe will clash and it will be hard do distinguish which of them should execute its actions. The same case is with the browser: it responds to all swipes and pans.. so should not be put in almost any scrolling control!!

Now, having said that, I want to tell you it is possible to overcame it - although it may turn not easy, depending on your actual case.

The most trivial thing to do, if you want to still be notified about the gestures is to use GestureService/GestureListener from the Silverlight Toolkit library. Even when the WebBrowser extinguishes the raw manipulations events, the GestureListener will still be able to notify you - because it apparently listens on some "other layer", I don't exactly want to get in to it now. Just fetch the library, add-reference it, do something like:

GestureService.GetListener( targetcontrol ).Flick( myBrowserFlickHandler );

and it's done - you get the notification whenever someone flicks on the control, with completely no regard of the manipulation events being e.handled=true or not. Small disclaimer here: I don't remember if on 7.0 it works, because the WebBrowser is build a bit differenlty there. On 7.1 and 7.5 it should work.

However, if you apply that on a WebBrowser - you will get the notif - but the webbrowser will get it too. That means, that 2 controls will react, and it turn to be visually quite rejecting if you start some storyboards from within the handler..

On 7.1 and almost-current 7.5, it is possible to play hard with the WebBrowser and to completely control which manipulation-event it will see. Thus, by filtering the mani-events for the WB, and by using GestureListener to see the events yourself, you can both block the WB from doing anything, and at the same time you can respond with your own action instead. I've written about that extensively in a response to similar problem, see WP7 Pivot control and a WebBrowser control for details. It is not a quick/easy/funny thing to do though.

EDIT: and MOST importantly, it is NOT guaranteed to work in the future. Throughout the 7.1 and 7.5 SDK/OS/API versions, inside the WebBrowser control some major internal undergoing changes are visible, and I would not be surprised, if it would dramatically change in the next few releases. Don't play with the things I've wrote there about if you do not want to have to revisit the subject again in the next 1-2 years.

Answer 2

This is a consequence of the way we implemented WebBrowser. The touch events are handed off directly to the browser engine. Once that happens Silverlight is basically out of the picture. Unfortunately I can't think of any workarounds that might give you what you want. -Skeets, MS dev