<Window x:Class="Main"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="" Height="300" Width="300">
<Grid>
<Path Stroke="Black" StrokeThickness="1">
<Path.Data>
<GeometryGroup>
<LineGeometry x:Name="line2" StartPoint="38,40" EndPoint="248,40" />
</GeometryGroup>
</Path.Data>
<Path.Triggers>
<EventTrigger RoutedEvent="Path.Loaded">
<BeginStoryboard>
<Storyboard AutoReverse="True" RepeatBehavior="Forever">
<PointAnimation To="280,40" Storyboard.TargetName="line2" Storyboard.TargetProperty="StartPoint" />
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</Path.Triggers>
</Path>
</Grid>
</Window>