Problems centering Image inside in a SettingsCard

[mikeclayton]

I'm currently struggling with getting an Image to centre inside a SettingsCard, so I'm hoping someone can give me some pointers...

I'm kind of new to the Community Toolkit controls, and tbh I'm kind of new to WinUI / Xaml in general so I may be trying to do something daft - let me know if there's better way of doing what I'm doing.

Desired Layout

This is what I'm hoping to do... I have a SettingsExpander with a nested SettingsCard that contains an Image control. I'd like the Image to be centred horizontally within the SettingsCard:

(arrowed lines just for illustration - not part of the UI)

Actual Layout

Here's the Xaml I'm using, which is as close as I've been able to get to my desired layout.

<UserControl
    ... snip ...
    xmlns:tkcontrols="using:CommunityToolkit.WinUI.Controls"
    >

    <controls:SettingsGroup>

        <tkcontrols:SettingsExpander
            x:Uid="MouseUtils_MouseJump_Appearance"
            HeaderIcon="{ui:FontIcon Glyph=&#xEB3C;}"
            IsEnabled="{x:Bind ViewModel.IsMouseJumpEnabled, Mode=OneWay}"
            IsExpanded="False">
            <tkcontrols:SettingsExpander.Items>

                <tkcontrols:SettingsCard
                    HorizontalAlignment="Center">
                    <Image Source="{x:Bind Path=ViewModel.MouseJumpPreviewImage, Mode=OneWay}" />
                </tkcontrols:SettingsCard>

            </tkcontrols:SettingsExpander.Items>
        </tkcontrols:SettingsExpander>

    </controls:SettingsGroup>

</UserControl>

However, this rendered as:

Problems

The problems I have are:

• The SettingsCard seems to no longer fill the width of the SettingsExpander - there's light grey background visible either side of it.

• The Image isn't perfectly centred in the SettingsCard - I think this is because there's space reserved for the HeaderIcon, but I've not been able to work out how to remove that space (HeaderIcon="" causes an exception, and I'm not sure what other values / settings I could use to remove the HeaderIcon).

This UserControl is part of a much bigger project, so it's possible there's some global configuration settings being applied that I'm unaware of - I can give links to source if needed.

Any suggestions on what to try would be welcome...

[mikeclayton]

I managed to put a workaround together - it's not pretty but it works.

The first part was to wrap the image in a Grid and StackPanel to allow it to centre property inside the "content" area of the SettingsCard:

<UserControl
    ... snip ...
    xmlns:tkcontrols="using:CommunityToolkit.WinUI.Controls"
    >

    <controls:SettingsGroup>

        <tkcontrols:SettingsExpander
            x:Uid="MouseUtils_MouseJump_Appearance"
            HeaderIcon="{ui:FontIcon Glyph=&#xEB3C;}"
            IsEnabled="{x:Bind ViewModel.IsMouseJumpEnabled, Mode=OneWay}"
            IsExpanded="False">
            <tkcontrols:SettingsExpander.Items>

                <tkcontrols:SettingsCard
                    x:Name="MouseUtils_MouseJump_PreviewImage"
                    MinHeight="300"
                    MaxHeight="300"
                    Loaded="PreviewImage_Loaded">
                    <Grid
                        MinHeight="283"
                        MaxHeight="283"
                        HorizontalAlignment="Stretch"
                        VerticalAlignment="Stretch">
                        <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
                            <Image Source="{x:Bind Path=ViewModel.MouseJumpPreviewImage, Mode=OneWay}" Stretch="None" />
                        </StackPanel>
                    </Grid>

            </tkcontrols:SettingsExpander.Items>
        </tkcontrols:SettingsExpander>

    </controls:SettingsGroup>

</UserControl>

The second part was to inspect the source code for the CommunityToolkit library and find the names of the private / internal controls so I could use get references to them and hide them - this expands the "content" area to fill the entire SettingsCard:

        private void PreviewImage_Loaded(object sender, RoutedEventArgs e)
        {
            bool TryFindFrameworkElement(SettingsCard settingsCard, string partName, out FrameworkElement result)
            {
                result = settingsCard.FindDescendants()
                    .OfType<FrameworkElement>()
                    .FirstOrDefault(
                        x => x.Name == partName);
                return result is not null;
            }

            /*
                apply a variation of the "Left" VisualState for SettingsCards
                to center the preview image in the true center of the card
                see https://github.com/CommunityToolkit/Windows/blob/9c7642ff35eaaa51a404f9bcd04b10c7cf851921/components/SettingsControls/src/SettingsCard/SettingsCard.xaml#L334-L347
            */

            var settingsCard = (SettingsCard)sender;

            var partNames = new List<string>
            {
                "PART_HeaderIconPresenterHolder",
                "PART_DescriptionPresenter",
                "PART_HeaderPresenter",
                "PART_ActionIconPresenter",
            };
            foreach (var partName in partNames)
            {
                if (!TryFindFrameworkElement(settingsCard, partName, out var element))
                {
                    continue;
                }

                element.Visibility = Visibility.Collapsed;
            }

            if (TryFindFrameworkElement(settingsCard, "PART_ContentPresenter", out var content))
            {
                Grid.SetRow(content, 1);
                Grid.SetColumn(content, 1);
                content.HorizontalAlignment = HorizontalAlignment.Center;
            }
        }

This results in the following, with the image properly centred in the otherwise-empty SettingsCard:

There's a danger this might break if the internals of the SettingsCard library change, but it works for the time being, and I couldn't see a way to do it using just the public interface...