I have the next code in my view:
<Style x:Key="documentFileNameStyle">
<Setter Property="TextBlock.Foreground" Value="Gray"/>
<Style.Triggers>
<DataTrigger Binding="{Binding Path=Untitled}" Value="True">
<Setter Property="TextBlock.FontStyle" Value="Italic"/>
<Setter Property="TextBlock.Text" Value="no file name"/>
</DataTrigger>
</Style.Triggers>
</Style>
<DataTemplate x:Key="documentTemplate">
<TextBlock Text="{Binding Path=FileName}" Style="{StaticResource documentFileNameStyle}"/>
</DataTemplate>
But setting TextBlock.Text to a string didn't work. TextBlock.FontStyle changes to Italic, so whole trigger works properly. What is wrong?