[CollectionView][iOS] CollectionView with a CollectionView with LinearItemsLayout set to Horizontal in its Header fills the CollectionView with blank space

[Vetle444]

Description

If you have a default CollectionView, putting a CollectionView that has <LinearItemsLayout Orientation="Horizontal" /> in its header fills the outer CollectionView with a lot of blank space. I'm not sure if this is good practice, however this worked in .NET MAUI 9.0.10 (Did not test 9.0.20).

Code:

<CollectionView>
        
        <CollectionView.ItemsSource>
            <x:Array Type="{x:Type x:String}">
                <x:String>First</x:String>
                <x:String>Second</x:String>
                <x:String>Third</x:String>
            </x:Array>
        </CollectionView.ItemsSource>
        
        <CollectionView.Header>
            <CollectionView>
                <CollectionView.ItemsLayout>
                    <LinearItemsLayout Orientation="Horizontal" />
                </CollectionView.ItemsLayout>
                
                <CollectionView.ItemsSource>
                    <x:Array Type="{x:Type x:String}">
                        <x:String>First</x:String>
                        <x:String>Second</x:String>
                        <x:String>Third</x:String>
                    </x:Array>
                </CollectionView.ItemsSource>
                
                <CollectionView.ItemTemplate>
                    <DataTemplate>
                        <Label Text="{Binding .}" />
                    </DataTemplate>
                </CollectionView.ItemTemplate>
                
            </CollectionView>
        </CollectionView.Header>

        <CollectionView.ItemTemplate>
            <DataTemplate>
                <Label Text="{Binding .}" />
            </DataTemplate>
        </CollectionView.ItemTemplate>
        
    </CollectionView>

As you can see, the CollectionView's items is pushed far down, however, the header that has the CollectionView displays the text correctly.

Steps to Reproduce

1. Create a new ContentPage
2. Put the code above as the content

Link to public reproduction project repository

No response

Version with bug

9.0.30 SR3

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

9.0.10 SR1

Affected platforms

iOS

Affected platform versions

iOS >=17.5

Did you find any workaround?

Rewriting to use BindableLayout together with HorizontalStackLayout and ScrollView

Relevant log output

[RoiChen001]

I can repro this issue at iOS platform on the latest 17.13 Preview 2.1(9.0.30), but it works fine at 9.0.10.

[rmarinho]

This happens on cv1 and cv2 on main right now.

[kubaflo]

Hi! @Vetle444 could you please attach a sample to a project that works>. I cannot reproduce working behavior on net 9.0.10

With the following MainPage:

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MauiSandbox.MainPage">

    <CollectionView>

        <CollectionView.ItemsSource>
            <x:Array Type="{x:Type x:String}">
                <x:String>First</x:String>
                <x:String>Second</x:String>
                <x:String>Third</x:String>
            </x:Array>
        </CollectionView.ItemsSource>

        <CollectionView.Header>
            <CollectionView>
                <CollectionView.ItemsLayout>
                    <LinearItemsLayout Orientation="Horizontal"/>
                </CollectionView.ItemsLayout>

                <CollectionView.ItemsSource>
                    <x:Array Type="{x:Type x:String}">
                        <x:String>First</x:String>
                        <x:String>Second</x:String>
                        <x:String>Third</x:String>
                    </x:Array>
                </CollectionView.ItemsSource>

                <CollectionView.ItemTemplate>
                    <DataTemplate>
                        <Label Text="{Binding .}"/>
                    </DataTemplate>
                </CollectionView.ItemTemplate>

            </CollectionView>
        </CollectionView.Header>

        <CollectionView.ItemTemplate>
            <DataTemplate>
                <Label Text="{Binding .}"/>
            </DataTemplate>
        </CollectionView.ItemTemplate>

    </CollectionView>
</ContentPage>

The app is not loading for me