Description

In .NET 9, I was popping bottom sheets using platform-specific code for Android and IOS. I passed a ContentView to my Maui wrapper code, and it placed it inside a "native" bottom sheet on the target platforms.

Android naturally sized to layed-out dimensions of the content view, wrapping it without extra effort. For IOS, I needed to create a custom detente with a specific height, which I did by measuring the ContentView (calling the Measure method).

This measure operation stopped working in .NET 10. for ContentViews that contain a ColllectionView I'm not sure exactly what size it is returning (doesn't match a single entry sizing), but does not contain the full list of items in my CollectionView.

My VerticalStackLayout pages that are bound to items work fine, and measure does as expected. The ContentView that contains a CollectionView does not.

I figure this applies to more than my native bottomsheet logic, so raising it as a bug.

Steps to Reproduce

See sample code uploaded below.

SampleMeasureIssue.zip

Link to public reproduction project repository

No response

Version with bug

10.0.11

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

9.0.120 SR12

Affected platforms

iOS

Affected platform versions

IOS 26.1

Did you find any workaround?

I'm using an interface to let my content view manually declare its height using an optional interface (fortunately, each item is consistent in this particular bottom sheet chooser), but will not work as easily if the heights vary.

Update Dec 4, 2025: I figured out that reverting to the old CollectionView handler also works (the one that was used in .net 9). .NET 10 has a new handler, and that is the one with the measurement issue.

Relevant log output