ui:TextBlock Style Triggers Not Applying

[p6laris]

Hey Folks,

I’ve run into a bit of a wall trying to apply a Style with a DataTrigger to a ui:TextBlock. I’m trying to change the foreground color based on a boolean ViewModel.IsValid property, but the trigger just never seems to fire. I’ve confirmed the binding works in other controls like Border, but not with ui:TextBlock.

    <Style
        BasedOn="{StaticResource {x:Type TextBlock}}"
        TargetType="{x:Type ui:TextBlock}"
        x:Key="KeyTextStyle">
        <Setter Property="Foreground" Value="Black" />
        <Style.Triggers>
            <DataTrigger Binding="ViewModel.IsValid}" Value="False">
                <Setter Property="Foreground" Value="{StaticResource SecondaryErrorBrush}" />
            </DataTrigger>
        </Style.Triggers>
    </Style>