WPF, button inheriting Foreground for its content - wpf

Question

The problem: how can I design button, which inherits Foreground from its parent, but allows changing it via style?
More precisely, given following button:
<StackPanel TextBlock.Foreground="Red">
<ToggleButton Width="16" Height="16" FontSize="10" Style="{StaticResource ...}">
<Grid>
<Path Width="8" Height="8" Fill="...">
<Path.Data>
<PathGeometry Figures="M 1 0 L 1 4 L 0 4 L 0 5 L 3 5 L 3 8 L 4 8 L 4 5 L 7 5 L 7 4 L 6 4 L 6 0 L 1 0 z M 2 1 L 4 1 L 4 4 L 2 4 L 2 1 z " FillRule="NonZero"/>
</Path.Data>
</Path>
</Grid>
</ToggleButton>
</StackPanel>
I need, that:
Path's fill color matches StackPanel's current Foreground color, and
When user hovers mouse over the button, path's fill color becomes some specific, constant color.
I tried designing style for button, including the ControlTemplate, but there's a problem with Foreground. Button has its Foreground property set to some DynamicResource via theme, so it doesn't match StackPanel's Foreground.
Obviously I can bind it, but then style and control template triggers stops working, because I've set an immediate value to a dependency property, what overrules all other means of providing value to it.
To give a context to the problem, this is what I want to achieve:

Answer 1

You could bind to the attached TextBlock.Foreground of the ToggleButton's parent Panel like this:
<Path Width="8" Height="8"
Fill="{Binding (TextBlock.Foreground),
RelativeSource={RelativeSource AncestorType=Panel, AncestorLevel=2}}">
...
If you want the Fill to change on mouse over, you could define a Style with a DataTrigger:
<StackPanel TextBlock.Foreground="Red">
<ToggleButton Width="16" Height="16" FontSize="10">
<Grid>
<Path Width="8" Height="8">
<Path.Data>
<PathGeometry Figures="M 1 0 L 1 4 L 0 4 L 0 5 L 3 5 L 3 8 L 4 8 L 4 5 L 7 5 L 7 4 L 6 4 L 6 0 L 1 0 z M 2 1 L 4 1 L 4 4 L 2 4 L 2 1 z "
FillRule="NonZero"/>
</Path.Data>
<Path.Style>
<Style TargetType="Path">
<Setter Property="Fill" Value="{Binding (TextBlock.Foreground),
RelativeSource={RelativeSource AncestorType=Panel, AncestorLevel=2}}" />
<Style.Triggers>
<DataTrigger Binding="{Binding IsMouseOver,
RelativeSource={RelativeSource AncestorType=ToggleButton}}" Value="True">
<Setter Property="Fill" Value="Blue" />
</DataTrigger>
</Style.Triggers>
</Style>
</Path.Style>
</Path>
</Grid>
</ToggleButton>
</StackPanel>

Answer 2

I figured it out by myself - I forgot, that style setters may set bindings as well. The solution is following.
Style:
<Style TargetType="ButtonBase" x:Key="DocumentTabButtonStyle">
<Style.Setters>
<Setter Property="TextBlock.Foreground" Value="{Binding Path=(TextBlock.Foreground), RelativeSource={RelativeSource AncestorType=StackPanel}}" />
<Setter Property="Template">
...
</Setter>
</Style.Setters>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="TextBlock.Foreground" Value="{StaticResource DocumentButtonHoverForegroundBrush}"/>
</Trigger>
</Style.Triggers>
</Style>
Button:
<Button Style="{StaticResource DocumentTabButtonStyle}">
<Path Fill="{Binding Path=(TextBlock.Foreground), RelativeSource={RelativeSource AncestorType={x:Type Button}}}">
<Path.Data>
<PathGeometry Figures="M 0 1 L 3 4 L 0 7 L 2 7 L 4 5 L 6 7 L 8 7 L 5 4 L 8 1 L 6 1 L 4 3 L 2 1 Z" />
</Path.Data>
</Path>
</Button>