[CarouselViewHandler2] Fir fox CurrentItem does not work when ItemSpacing is set #32135

SyedAbdulAzeemSF4852 · 2025-10-22T05:31:35Z

Note

Are you waiting for the changes in this PR to be merged?
It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!

Issue Details

CurrentItem does not update when ItemSpacing is set.

Root Cause

When ItemSpacing is set on a CarouselView using CV2 (CarouselViewHandler2), the page calculation logic was only considering the container size but ignoring the additional space consumed by ItemSpacing.

Description of Change

Updated the page index calculation in LayoutFactory2.cs to include ItemSpacing when determining the current page in the carousel layout. This ensures that CurrentItem updates correctly when spacing is present.

Issues Fixed

Fixes #32048

Validated the behaviour in the following platforms

Windows
Android
iOS
Mac

Output

Before	After
Before.mov	After.mov

…nts CurrentItem from updating correctly

dotnet-policy-service · 2025-10-22T05:31:50Z

Hey there @@SyedAbdulAzeemSF4852! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

jsuarezruiz · 2025-10-22T05:53:12Z

/azp run

azure-pipelines · 2025-10-22T05:53:35Z

Azure Pipelines successfully started running 3 pipeline(s).

jsuarezruiz · 2025-10-22T10:35:13Z

src/Controls/src/Core/Handlers/Items2/iOS/LayoutFactory2.cs


-				var page = (offset.X + sectionMargin) / (env.Container.ContentSize.Width - sectionMargin * 2);
+				// Calculate page index accounting for ItemSpacing
+				var itemSpacing = itemsView.ItemsLayout is LinearItemsLayout linearLayout ? linearLayout.ItemSpacing : 0;


Can you scroll to the very last item and verify CurrentItem updates correctly?

@jsuarezruiz , I have verified this by scrolling to the last item, and the CurrentItem is updating correctly. For your reference, I’m attaching the video below.

ScrollingToLastItem.mov

jsuarezruiz · 2025-10-22T10:35:22Z

src/Controls/src/Core/Handlers/Items2/iOS/LayoutFactory2.cs


-				var page = (offset.X + sectionMargin) / (env.Container.ContentSize.Width - sectionMargin * 2);
+				// Calculate page index accounting for ItemSpacing
+				var itemSpacing = itemsView.ItemsLayout is LinearItemsLayout linearLayout ? linearLayout.ItemSpacing : 0;


Can you verify also GridItemsLayout?

@jsuarezruiz , CarouselView.ItemsLayout is explicitly typed as LinearItemsLayout (not the base ItemsLayout type), so it cannot be a GridItemsLayout.

Looking at the CarouselView class definition :

maui/src/Controls/src/Core/Items/CarouselView.cs

Lines 194 to 198 in 12b0495

public LinearItemsLayout ItemsLayout

{

get => (LinearItemsLayout)GetValue(ItemsLayoutProperty);

set => SetValue(ItemsLayoutProperty, value);

}

The property type system enforces that only LinearItemsLayout can be assigned.

jsuarezruiz · 2025-10-22T10:41:06Z

src/Controls/src/Core/Handlers/Items2/iOS/LayoutFactory2.cs

+				var itemSpacing = itemsView.ItemsLayout is LinearItemsLayout linearLayout ? linearLayout.ItemSpacing : 0;
+
+				var effectiveItemWidth = env.Container.ContentSize.Width - sectionMargin * 2 + itemSpacing;
+				double page = (offset.X + sectionMargin) / effectiveItemWidth;


double page = (offset.X + sectionMargin) / effectiveItemWidth;

Could effectiveItemWidth be zero? Potential Divide-by-Zero Exception?

@jsuarezruiz , Yes, there is a potential divide-by-zero exception that could occur when the container has no width or when the effective item width calculation results in zero or a negative value. To prevent this, I've added a guard to skip the scroll calculation in such cases, avoiding invalid position updates.

…ve item width is zero or negative

Copilot

Pull Request Overview

This PR fixes a bug in CarouselView2 where the CurrentItem property fails to update correctly when ItemSpacing is configured. The root cause was that the page index calculation only considered container size without accounting for the additional space consumed by ItemSpacing.

Key Changes:

Updated page index calculation logic in iOS LayoutFactory2 to include ItemSpacing in the effective item width
Added validation to prevent division by zero when effectiveItemWidth is non-positive
Added comprehensive UI tests to validate the fix across platforms

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/Controls/src/Core/Handlers/Items2/iOS/LayoutFactory2.cs	Updated page index calculation to account for ItemSpacing in CarouselView layout
src/Controls/tests/TestCases.HostApp/Issues/Issue32048.cs	Added HostApp UI test page demonstrating the CurrentItem update with ItemSpacing
src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue32048.cs	Added NUnit test to verify CurrentItem updates correctly when ItemSpacing is set

Copilot · 2025-10-22T13:39:33Z

src/Controls/src/Core/Handlers/Items2/iOS/LayoutFactory2.cs

 				}

-				var page = (offset.X + sectionMargin) / (env.Container.ContentSize.Width - sectionMargin * 2);
+				// Calculate page index accounting for ItemSpacing


[nitpick] The comment on line 346 should clarify why itemSpacing is added to the effective width calculation. The current comment states 'accounting for ItemSpacing' but doesn't explain that the spacing is added because each item's scroll distance includes both its width and the spacing after it.

Suggested change

// Calculate page index accounting for ItemSpacing

// Calculate page index, including ItemSpacing because each item's scroll distance

// consists of its width plus the spacing after it. This ensures paging accounts for

// both the item width and the space between items.

azure-pipelines · 2025-10-22T13:47:41Z

Azure Pipelines successfully started running 3 pipeline(s).

SyedAbdulAzeemSF4852 added 2 commits October 21, 2025 12:23

Fix for issue in CarouselViewHandler2 where setting ItemSpacing preve…

b208402

…nts CurrentItem from updating correctly

Modified the fix and Added test case

5dab21d

dotnet-policy-service bot added the community ✨ Community Contribution label Oct 22, 2025

dotnet-policy-service bot added the partner/syncfusion Issues / PR's with Syncfusion collaboration label Oct 22, 2025

jsuarezruiz added the area-controls-collectionview CollectionView, CarouselView, IndicatorView label Oct 22, 2025

sheiksyedm added the platform/ios label Oct 22, 2025

jsuarezruiz requested changes Oct 22, 2025

View reviewed changes

Added a guard to prevent invalid layout calculations when the effecti…

6a473e3

…ve item width is zero or negative

SyedAbdulAzeemSF4852 marked this pull request as ready for review October 22, 2025 13:39

Copilot AI review requested due to automatic review settings October 22, 2025 13:39

Copilot AI reviewed Oct 22, 2025

View reviewed changes

jfversluis mentioned this pull request Oct 22, 2025

[CarouselViewHandler2] CurrentItem does not work when ItemSpacing is set #32048

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[CarouselViewHandler2] Fir fox CurrentItem does not work when ItemSpacing is set #32135

[CarouselViewHandler2] Fir fox CurrentItem does not work when ItemSpacing is set #32135

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jsuarezruiz commented Oct 22, 2025 •

edited by jfversluis

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	public LinearItemsLayout ItemsLayout
	{
	get => (LinearItemsLayout)GetValue(ItemsLayoutProperty);
	set => SetValue(ItemsLayoutProperty, value);
	}

-				// Calculate page index accounting for ItemSpacing
+				// Calculate page index, including ItemSpacing because each item's scroll distance
+				// consists of its width plus the spacing after it. This ensures paging accounts for
+				// both the item width and the space between items.

[CarouselViewHandler2] Fir fox CurrentItem does not work when ItemSpacing is set #32135

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[CarouselViewHandler2] Fir fox CurrentItem does not work when ItemSpacing is set #32135

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SyedAbdulAzeemSF4852 commented Oct 22, 2025

Issue Details

Root Cause

Description of Change

Issues Fixed

Validated the behaviour in the following platforms

Output

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Pull Request Overview

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jsuarezruiz commented Oct 22, 2025 •

edited by jfversluis

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