How to change a path fill (on a button) with triggers in XAML
You may bind Path.Fill to the Foreground property of the Button and modify the Foreground in a Button Style:
<Button Name="Test_Button" Width="220" Height="80" Padding="2"> <Canvas Width="76" Height="76" Clip="F1 M 0,0L 76,0L 76,76L 0,76L 0,0"> <Path Canvas.Left="19" Canvas.Top="19" Width="38" Height="38" Stretch="Fill" Fill="{Binding Foreground, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Button}}" Data="F1 M 35,19L 41,19L 41,35L 57,35L 57,41L 41,41L 41,57L 35,57L 35,41L 19,41L 19,35L 35,35L 35,19 Z"> </Path> </Canvas> <Button.Style> <Style TargetType="Button"> <Style.Triggers> <Trigger Property="IsMouseOver" Value="True"> <Setter Property="Foreground" Value="Red" /> </Trigger> <Trigger Property="IsMouseOver" Value="False"> <Setter Property="Foreground" Value="Gray" /> </Trigger> </Style.Triggers> </Style> </Button.Style></Button>