Pointerover style selector with condition from vm

[Tabidou]

I have created a custom style for ListBox and ListBoxItem controls.
I'm trying to condition the appearance of the pointerover in the ListBoxItem control.

My viewmodel contains a property called IsNotEditing (checking if any item is being edited) that I can access from the ListBoxItem using:
{Binding $parent[ListBox].((vm:PPViewModel)DataContext).IsNotEditing}

I also have a pointerover style to invert the colors:
<Style Selector="^:pointerover"> <Setter Property="Background" Value="{DynamicResource ForegroundColor}" /> <Setter Property="Foreground" Value="{DynamicResource BackgroundColor}" /> </Style>

I'm trying to get this pointerover to not enable when editing any item of the list.
So I'm adding a condition, and both these work as expected:
<Style Selector="^:pointerover[IsEnabled=true]"> (pointerover is enabled)
<Style Selector="^:pointerover[IsEnabled=false]"> (pointerover is disabled)

So now I'm trying to combine these:
<Style Selector="^:pointerover[IsEnabled="{Binding $parent[ListBox].((vm:PPViewModel)DataContext).IsNotEditing}"]">

But unfortuately, this doesn't work.
Is this even possible, am I just failing at the syntax ?
Or should this be achieved differently ?

Thanks in advance.

[stevemonaco]

Selectors do not support binding expressions.

This will be difficult pre-11.3.0. You need to apply a class binding to the ListBoxItem itself and then select on said class. Which may require making a custom ListBoxItem or ListBox with the appropriate ItemContainerGenerator.

See #16938 for how to do this on 11.3.0.

You'll also want to target the ContentPresenter instead of the ListBoxItem.Background directly, see:

Avalonia/src/Avalonia.Themes.Simple/Controls/ListBoxItem.xaml

Lines 25 to 27 in 808c86f

	<Style Selector="^:pointerover /template/ ContentPresenter">
	<Setter Property="Background" Value="{DynamicResource ThemeControlHighlightMidBrush}" />
	</Style>

[Tabidou]

I can use 11.3, not a problem.

I see the general logic from #16938, and that seems like a lot more above my knowledge level for the moment (but I'll try anyway !)

Thanks

[Tabidou]

Nevermind, I think I actually did it.
Is this what you expected ? (wondering if there are things I can "improve". I might remove the double negation on Classes.PointerOver.)

<ControlTheme x:Key="{x:Type ListBoxItem}" TargetType="ListBoxItem">
    <Setter Property="Background" Value="Transparent" />
    <Setter Property="Foreground" Value="{DynamicResource ForegroundColor}" />
    <Setter Property="Padding" Value="4" />
    <Setter Property="(Classes.PointerOver)" Value="{Binding !$parent[ListBox].((vm:PPViewModel)DataContext).IsNotEditing}" />
    <Setter Property="Template">
        <ControlTemplate>
            <ContentPresenter
                Name="PART_ContentPresenter"
                Padding="{TemplateBinding Padding}"
                VerticalContentAlignment="Center"
                Background="{TemplateBinding Background}"
                Content="{TemplateBinding Content}"
                ContentTemplate="{TemplateBinding ContentTemplate}"
                CornerRadius="5"
                Foreground="{TemplateBinding Foreground}" />
        </ControlTemplate>
    </Setter>

    <Style Selector="^:pointerover:not(ListBoxItem.PointerOver) /template/ ContentPresenter#PART_ContentPresenter">
        <Setter Property="Background" Value="{DynamicResource ForegroundColor}" />
        <Setter Property="Foreground" Value="{DynamicResource BackgroundColor}" />
    </Style>
</ControlTheme>

[stevemonaco]

Pretty close. You should probably start with a copy/pasted ControlTheme of ListBoxItem in whatever theme you're using or use a BasedOn. You're missing a lot of important states, like :selected.

^:pointerover:not(ListBoxItem.PointerOver) should be ^:pointerover:not(.PointerOver). Or really, .PointerOver should be renamed to something that actually matches: like .editing. You need to fix up the colors to refer to different brushes, etc.

But otherwise, that's the approach.

[Tabidou]

Yeah, my ControlTheme is very minimal and only what I needed as I have only one List, but I should use it as a BasedOn.
I'll take into account the other comments.
Thanks again for the time spent helping me.