pointerMoved not firing on Canvas inside ScrollViewer

mfe userlast 21

Hi,

I have in my scrollviewer an image and I wanted to be informed when the PointerReleased is fired. But it looks like only the PointerEntered event is fired correctly.

            <ScrollViewer x:Name="_ScrollViewer"
                          ZoomMode="Enabled" VerticalScrollMode="Auto" 
                          HorizontalScrollMode="Enabled" HorizontalScrollBarVisibility="Auto"
                          >

                <Image x:Name="image"  
                       CacheMode="BitmapCache"
                       MaxWidth="{Binding Path=ViewportWidth, ElementName=_ScrollViewer}"
                       MaxHeight="{Binding Path=ViewportHeight, ElementName=_ScrollViewer}"
                       Source="{Binding Path=SelectedImage.Stream,UpdateSourceTrigger=PropertyChanged,
                       Converter={StaticResource ResourceKey=StoreFileToBitmapImageConverter},
                    ConverterParameter={StaticResource disposeBool}}"
                        PointerEntered="PointerEntered"
                       PointerReleased="PointerExited"
                        >

Richard Zhang-MSFT 6,936 Reputation points

2020-10-12T01:26:30.057+00:00

Hello @mfe userlast , the reverse event corresponding to PointerEntered is PointerExited. PointerReleased is usually triggered when the pointer is released (for example, when the left mouse button is released). Is the PointerExited event you want to listen for?
mfe userlast 21 Reputation points

2020-10-17T09:44:35.667+00:00

Hi @Richard Zhang-MSFT
I want to track a left or right "swipe". I'm using the PointerEntered and PointerReleased event to detect those kind of swipes (Windows.Devices.Input.PointerDeviceType.Touch). If the image is contained in a scrollviewer the PointerReleased event is not fired. Using the PointerExited does not help, as the swipe gesture is happening inside the Image control.
I'm currently think of a workaround using PointeredEntered and PointerMoved.
Richard Zhang-MSFT 6,936 Reputation points

2020-10-19T01:23:26.857+00:00

Hello @mfe userlast , ScrollViewer will intercept part of the bubbling of Pointer events for internal processing of its own events. If you need gesture operations, you can consider using GestureRecognizer, which provides some unique events (such as CrossSliding, which can be used to recognize swipe operations)
Richard Zhang-MSFT 6,936 Reputation points

2020-10-23T08:52:29.99+00:00

Hello, has your problem been resolved? If you have other questions, please feel free to ask
mfe userlast 21 Reputation points

2020-10-24T07:46:15.1+00:00

Currently my only touch device the Surface pro still won’t turn on, I can't test it :'(
Richard Zhang-MSFT 6,936 Reputation points

2020-10-26T08:03:53.19+00:00

Hello @mfe userlast , don’t worry, you can test it at your convenience, if there are follow-up updates, you can continue to publish it. :)
mfe userlast 21 Reputation points

2021-02-06T14:40:17.69+00:00

Hi,
got my surface back :). It looks like that the PointerMoved is not fired with PointerDeviceType.Touch in combination with a ScrollViewer. Therefore I tried to call CancelDirectmanipulation on the scrollviwer (as stated in the doc https://learn.microsoft.com/en-us/windows/uwp/design/input/touch-interactions ) but it always returns false.

If you need to handle pointer events for a UIElement in a scrollable view (such as a ScrollViewer or ListView), you must explicitly disable support for manipulation events on the element in the view by calling UIElement.CancelDirectmanipulation(). To re-enable manipulation events in the view, call UIElement.TryStartDirectManipulation().

I created a repo where the issue occours:
https://github.com/mfe-/App1SwipeOnScrollView

Any idea @Richard Zhang-MSFT ?

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pointerMoved not firing on Canvas inside ScrollViewer

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