<Label Text="Hello World!">
<Label.Triggers>
<DataTrigger TargetType="Label" Binding="{Binding IsActive}" Value="false">
<Setter Property="Text" Value="Not Active" />
</DataTrigger>
<DataTrigger TargetType="Label" Binding="{Binding IsActive}" Value="true">
<Setter Property="Text" Value="Active" />
</DataTrigger>
</Label.Triggers>
</Label>