[iOS] CarouselView throws NSInternalInconsistencyException with data templates and template selector #39211

Description

On iOS attempting to use a CarouselView with data templates and a template selector fails with a ObjCRuntime.CObjCException: "Name: NSInternalInconsistencyException Reason: Attempted to dequeue a cell for a different registration or reuse identifier than the existing cell when reconfiguring an item, which is not allowed. You must dequeue a cell using the same registration or reuse identifier that was used to dequeue the cell originally to obtain the existing cell."

Steps to Reproduce

MauiCarouselView.zip

See the attached repro project. Also available at: https://github.com/jbcomp/JBCT-1948B-MauiCarouselView

The example shows a horizontally scrollable CarouselView with two items each with a different data template.

REPRO

As per the project, using Microsoft.Maui.Controls v10.0.110:

• On Android the carousel items are shown and it is possible to swipe horizontally between them. This functions correctly on all Android versions from 10 upwards.

• On iOS the repro fails immediately on launch with a ObjCRuntime.CObjCException: "Name: NSInternalInconsistencyException Reason: Attempted to dequeue a cell for a different registration or reuse identifier than the existing cell when reconfiguring an item, which is not allowed. You must dequeue a cell using the same registration or reuse identifier that was used to dequeue the cell originally to obtain the existing cell."

This has been verified on iOS 26.5 only, but probably applies to all versions.

REGRESSION

Modify to use Microsoft.Maui.Controls v10.0.90, and it functions as expected on iOS - the carousel items are shown and it is possible to swipe between them. This regression issue was introduce in Microsoft.Maui.Control v10.0.100.

Link to public reproduction project repository

https://github.com/jbcomp/JBCT-1948B-MauiCarouselView

Version with bug

10.0.110

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

10.0.90

Affected platforms

iOS

Affected platform versions

No response

Did you find any workaround?

Only by reverting to the earlier handler:

#if IOS || MACCATALYST
builder.ConfigureMauiHandlers(handlers =>
{
handlers.AddHandler<
Microsoft.Maui.Controls.CarouselView,
Microsoft.Maui.Controls.Handlers.Items.CarouselViewHandler>();
});
#endif

Relevant log output