[XAML]
<Page
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" >
<!-- For demonstration purposes, animate ProgressBar.Value
-->
<Page.Triggers>
<EventTrigger RoutedEvent='Page.Loaded'>
<BeginStoryboard>
<Storyboard TargetName='ProgressBar'
TargetProperty='Value'>
<DoubleAnimation From='0' To='100' Duration='0:0:1' />
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</Page.Triggers>
<Grid >
<ProgressBar Name='ProgressBar' />
<Viewbox>
<TextBlock>
<TextBlock.Style>
<Style TargetType='TextBlock'>
<!-- Make the text "Loading ..." by default-->
<Setter Property='Text' Value='Loading ...' />
<!-- But when ProgressBar.Value is 100, change the text to
"Complete" -->
<Style.Triggers>
<DataTrigger Binding='{Binding Value,
ElementName=ProgressBar}' Value='100'>
<Setter Property='Text' Value='Complete' />
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
</Viewbox>
</Grid>
</Page>