Fix for 2923: Ignore vertical scroll inside TabControl header. - #2924
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There is already a MainScrollViewer in place which handles the scrolling, so there is no need for the additional ScrollViewer; in fact this is what was causing scrolling not to work correctly when hovering the expanders.
Changed to file scoped namespace. Introduced attached property to effectively disable the vertical scroll on a ScrollViewer.
nicolaihenriksen
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Keboo
approved these changes
Oct 30, 2022
Keboo
approved these changes
Nov 3, 2022
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Fix for #2923
This PR introduces
ScrollViewerAssist.IgnoreVerticalScrollattached property which effectively allows a user to opt-in on disabling vertical scrolling in aScrollViewer. It works by registering for the already handledMouseWheelevent, and then bubbling a copy of that event on its parent element.A ScrollViewer will by default - as far as I know - consume (handled=true) the
MouseWheelevent, even if there is nothing for that particularScrollViewerto scroll in (i.e. all content is displayed and visible in the viewport). The problem in the issue mentioned above was that theTabControluses aScrollViewerinside its header to enable horizontal scrolling (if there is not enough room for the tabs I presume), but thatScrollViewerconsumes the verticalMouseWheelevents as well; effectively disabling scrolling all together when the mouse hovers theScrollViewer.In scenarios like these where you want "horizontal" scrolling only, you can apply the attached property mentioned above. You can argue that you could end up with double-scrolling if the nested
ScrollViewer(and the outerScrollViewer) actually CAN scroll vertically AND you apply this attached property. However I see that as a somewhat unlikely scenario... In those cases you should of course not use the attached property.I applied the attached property on the
ScrollViewerin theMaterialDesignTabControlBasestyle and also added a sample to the demo application to showcase that it still works with scrollable content inside of the tab control.The issue mentions that there is also a problem with the expander, but I believe that was just an issue in the demo application which had a not needed
ScrollVieweradded toExpander.xaml.