<Slider   xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" Height="29" Name="slider1" Width="218" IsSelectionRangeEnabled="True" SelectionStart="0"  IsSnapToTickEnabled="False" IsMoveToPointEnabled="False" IsDirectionReversed="False" TickPlacement="BottomRight" >
        <Slider.Triggers>
            <EventTrigger RoutedEvent="ProgressBar.Loaded">
                <BeginStoryboard>
                    <Storyboard>
                        <DoubleAnimation
				            Storyboard.TargetName="slider1"
				            Storyboard.TargetProperty="SelectionEnd"
				            From="0" To="10" Duration="0:0:15" 
                            RepeatBehavior="Forever" />
                    </Storyboard>
                </BeginStoryboard>
            </EventTrigger>
        </Slider.Triggers>
    </Slider>