The header in a collectionview does not resize if you hide the content

[acaliaro]

Description

If I have a collectionview with a header and the header container control has the "IsVisible" property bound to a boolean property in the ViewModel, when the boolean property is set to "false", the header content disappears but the space does not compress.
If on the contrary, in addition to the container I also set the "IsVisible" property of the content (e.g. an Image), the header content disappears and the header space compresses

Steps to Reproduce

• Create a page with a collectionview
• In the collectionView insert a header with a VerticalStackLayout
• In the VerticalStackLayout insert an image
• Set the "IsVisible" property of the VerticalStackLayout in binding with a boolean in the ViewModel.
• Use a Switch to set the boolean so as to display or not the image
• The image disappears but the header space does not compress

Link to public reproduction project repository

https://github.com/acaliaro/MauiAppCollectionViewHeaderProblem

Version with bug

9.0.40 SR4

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

iOS, Android

Affected platform versions

iOS 18.2.1, Android 35

Did you find any workaround?

By setting the IsVisible of the image as well, the header resizes correctly

Relevant log output

[similar-issues-ai]

We've found some similar issues:

• [iOS][9.0.30][CV1] The size of the CollectionView header is incorrect when it contains a Binding on an IsVisible #27200 , similarity score: 84%
• CollectionView Header size is broken on iOS with Microsoft.Maui.Controls v9.0.30 #27633 , similarity score: 81%

If any of the above are duplicates, please consider closing this issue out and adding additional context in the original issue.

Note: You can give me feedback by 👍 or 👎 this comment.

[kubaflo]

This might be fixed by: #20154

[kubaflo]

Confirming this PR helps :) #20154

Screen.Recording.2025-02-24.at.20.33.15.mov

<Grid ColumnDefinitions="*"
        RowDefinitions="auto, *, *">
    <HorizontalStackLayout Grid.Row="0"
                            Margin="10,0">
        <Label Text="Switch to show / hide headers"/>
        <Switch x:Name="Switch"/>

    </HorizontalStackLayout>
    <CollectionView Grid.Row="1"
                    BackgroundColor="Red"
                    SelectionMode="None"
                    VerticalScrollBarVisibility="Never">
        <CollectionView.Header>
            <VerticalStackLayout BackgroundColor="Beige"
                                    IsVisible="{Binding IsToggled, Source={x:Reference Switch}}">
                <Image BackgroundColor="Pink"
                        Source="dotnet_bot.png"/>
            </VerticalStackLayout>
        </CollectionView.Header>
        <CollectionView.ItemsSource>
            <x:Array Type="{x:Type x:String}">
                <x:String>Item 1</x:String>
                <x:String>Item 2</x:String>
                <x:String>Item 3</x:String>
                <x:String>Item 4</x:String>
            </x:Array>
        </CollectionView.ItemsSource>
        <CollectionView.ItemTemplate>
            <DataTemplate x:DataType="x:String">
                <VerticalStackLayout>
                    <Label Text="{Binding .}"/>
                </VerticalStackLayout>
            </DataTemplate>
        </CollectionView.ItemTemplate>
    </CollectionView>

    <CollectionView Grid.Row="2"
                    BackgroundColor="Blue"
                    SelectionMode="None"
                    VerticalScrollBarVisibility="Never">
        <CollectionView.Header>
            <VerticalStackLayout BackgroundColor="Beige">
                <Image BackgroundColor="Pink"
                        IsVisible="{Binding IsToggled, Source={x:Reference Switch}}"
                        Source="dotnet_bot.png"/>
            </VerticalStackLayout>
        </CollectionView.Header>
        <CollectionView.ItemsSource>
            <x:Array Type="{x:Type x:String}">
                <x:String>Item 1</x:String>
                <x:String>Item 2</x:String>
                <x:String>Item 3</x:String>
                <x:String>Item 4</x:String>
            </x:Array>
        </CollectionView.ItemsSource>
        <CollectionView.ItemTemplate>
            <DataTemplate x:DataType="x:String">
                <VerticalStackLayout>
                    <Label Text="{Binding .}"/>
                </VerticalStackLayout>
            </DataTemplate>
        </CollectionView.ItemTemplate>
    </CollectionView>
</Grid>

[acaliaro]

@kubaflo when do you think the PR will be merged and released?