<ProgressBar xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" Height="26" Name="progressBar" Width="225">
            <ProgressBar.Triggers>
                <EventTrigger RoutedEvent="ProgressBar.Loaded">
                    <BeginStoryboard>
                        <Storyboard>
                            <DoubleAnimation
				            Storyboard.TargetName="progressBar"
				            Storyboard.TargetProperty="Value"
				            From="0" To="100" Duration="0:0:5" 
                            RepeatBehavior="Forever" />
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger>
            </ProgressBar.Triggers>
        </ProgressBar>