<UserControl.Triggers>
    <EventTrigger RoutedEvent="Mouse.MouseWheel" >
        <BeginStoryboard Storyboard="{StaticResource OnMouseWheel1}"/>
    </EventTrigger>
</UserControl.Triggers>

<Canvas.Resources>
 <Storyboard x:Name="ZoomStoryboard">
       <DoubleAnimation x:Name="ZoomAnimationX"
                        Storyboard.TargetName="Workspace"
                    Storyboard.TargetProperty="Canvas.RenderTransform.ScaleTransform.ScaleX"
                             Duration="0:0:0.2"/>
            <DoubleAnimation x:Name="ZoomAnimationY"
                             Storyboard.TargetName="Workspace"
                             Storyboard.TargetProperty="Canvas.RenderTransform.ScaleTransform.ScaleY"
                             Duration="0:0:0.2"/>
        </Storyboard>
    </Canvas.Resources>