fix using touch for date/time pickers.

[danwalmsley]

What does the pull request do?

Fixes scrollgestures on date/time pickers

What is the current behavior?

handles events, and uses a transparent background so others are not picked up.

What is the updated/expected behavior with this PR?

How was the solution implemented (if it's not obvious)?

Checklist

• Added unit tests (if possible)?
• Added XML documentation to any related classes?
• Consider submitting a PR to https://github.com/AvaloniaUI/Documentation with user documentation

Breaking changes

Obsoletions / Deprecations

Fixed issues

@amwx

[avaloniaui-team]

You can test this PR using the following package version. 0.10.999-cibuild0019363-beta. (feed url: https://nuget.avaloniaui.net/repository/avalonia-all/index.json) [PRBUILDID]

[avaloniaui-team]

You can test this PR using the following package version. 0.10.999-cibuild0019369-beta. (feed url: https://nuget.avaloniaui.net/repository/avalonia-all/index.json) [PRBUILDID]

[amwx]

Tapped event probably makes more sense anyway so that change seems fine to me.

Though, we can get an invalid scrolling state with touch scrolling gesture where scroll can end up between items.

WinUI's ScrollViewer has snap points that I think automatically handle this - so I think the Offset just needs to be coerced in the property setter, probably something like if (dy % ItemHeight != 0) then snap to nearest but I don't have a full understanding of how the manipulation gestures work and if that would mess something else up

Avalonia/src/Avalonia.Controls/DateTimePickers/DateTimePickerPanel.cs

Lines 216 to 218 in d9f8339

	var old = _offset;
	_offset = value;
	var dy = _offset.Y - old.Y;

[jmacato]

@amwx yeah snapping to the nearest multiple of the item's height would be ideal

[maxkatz6]

Let's merge it as a small fix of single problem. Scroll snapping issue can be followed separately.
@amwx can you create a small issue from your comment? Thanks.

[avaloniaui-team]

You can test this PR using the following package version. 0.10.999-cibuild0019385-beta. (feed url: https://nuget.avaloniaui.net/repository/avalonia-all/index.json) [PRBUILDID]

[amwx]

Let's merge it as a small fix of single problem. Scroll snapping issue can be followed separately. @amwx can you create a small issue from your comment? Thanks.

Done (#7840). I'll try to do the fix too, as it should be pretty trivial to do