Set Datacontext of a control to a property - wpf

Question

I am trying to create a style for a textblock to create a highlight effect. This style will be used on a number of TextBlocks, each bound to a different property. The datacontext for my main control is set in code behind:
this.DataContext = dataobject;
I can create one textblock with a working binding like this:
<TextBlock Text="Field1">
<TextBlock.Style>
<Style x:Key="HighlightStyle" TargetType="{x:Type TextBlock}">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=.}" Value="True">
<Setter Property="Background" Value="Yellow"/>
<Setter Property="Foreground" Value="Black"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
<TextBlock>
But I need to change the binding so that the style can be used on different TextBlocks. Something like:
<Style x:Key="HighlightStyle" TargetType="{x:Type TextBlock}">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=.}" Value="True">
<Setter Property="Background" Value="Yellow"/>
<Setter Property="Foreground" Value="Black"/>
</DataTrigger>
</Style.Triggers>
</Style>
<TextBlock Text="Field1" DataContext="{Binding Path=BooleanProperty1}" Style="{StaticResource HighlightStyle}"/>
<TextBlock Text="Field2" DataContext="{Binding Path=BooleanProperty2}" Style="{StaticResource HighlightStyle}"/>
When I try this, changing the properties does nothing to highlight the textblock. Is there a way to accomplish this?

Answer 1

Could always abuse the tag property.
<Window x:Class="WpfApplication2.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
DataContext="{Binding RelativeSource={RelativeSource Self}}"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<Style TargetType="{x:Type TextBlock}">
<Style.Triggers>
<Trigger Property="Tag" Value="True">
<Setter Property="Background" Value="Yellow"/>
<Setter Property="Foreground" Value="Black"/>
</Trigger>
</Style.Triggers>
</Style>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<TextBlock Text="Field1" Grid.Row="0" Tag="{Binding Field1}"/>
<TextBlock Text="Field2" Grid.Row="1" Tag="{Binding Field2}"/>
</Grid>
</Window>
or if you're feeling adventurous you could create an attached dependency property and pass that over.
public class TextBlockExtender : DependencyObject
{
public static string GetMyDataField(DependencyObject obj)
{
return (string)obj.GetValue(MyDataFieldProperty);
}
public static void SetMyDataField(DependencyObject obj, string value)
{
obj.SetValue(MyDataFieldProperty, value);
}
public static readonly DependencyProperty MyDataFieldProperty =
DependencyProperty.RegisterAttached("MyDataField", typeof(string), typeof(TextBlockExtender), new PropertyMetadata(null));
}
used with XAML
<Window x:Class="WpfApplication2.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication2"
DataContext="{Binding RelativeSource={RelativeSource Self}}"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<Style TargetType="{x:Type TextBlock}">
<Style.Triggers>
<Trigger Property="local:TextBlockExtender.MyDataField" Value="True">
<Setter Property="Background" Value="Yellow"/>
<Setter Property="Foreground" Value="Black"/>
</Trigger>
</Style.Triggers>
</Style>
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<TextBlock Text="Field1" Grid.Row="0" local:TextBlockExtender.MyDataField="{Binding Field1}"/>
<TextBlock Text="Field2" Grid.Row="1" local:TextBlockExtender.MyDataField="{Binding Field2}"/>
</Grid>
</Window>