Binding a WPF Style Trigger to a custom dependency property - wpf

Question

I have found numerous similar threads here, but none that seem to address my specific issue.
I need to highlight the background of a textbox under certain conditions. I have created a Highlight property and tried using a trigger in a style to set it but it doesn't actually ever highlight the text.
Here is my Style, simplified:
<Style x:Key="TextBoxStyle" BasedOn="{StaticResource CommonStyles}">
<Style.Triggers>
<Trigger Property="Elements:DataElement.Highlight" Value="True">
<Setter Property="Control.Background"
Value="{DynamicResource EntryBoxHighlightBackground}"/>
</Trigger>
</Style.Triggers>
</Style>
Elements is defined as:
xmlns:Elements="clr-namespace:MDTCommon.Controls.Forms.Elements">
Then I have the section where the style is applied:
<!-- Applies above style to all TextBoxes -->
<Style TargetType="TextBox" BasedOn="{StaticResource TextBoxContentHolder}" >
<Setter Property="Validation.ErrorTemplate" Value="{x:Null}" />
<!-- Overrides the default Error Style -->
</Style>
In the code behind of the DataElement class is the following:
public static readonly DependencyProperty HighlightProperty =
DependencyProperty.Register("Highlight", typeof(bool), typeof(DataElement));
public bool Highlight
{
get { return (bool)base.GetValue(HighlightProperty); }
set { base.SetValue(HighlightProperty, value); }
}
A DataElement ultimately derived from UserControl and it contains a reference to TextBox object as well as othe objects.
In the CustomForm class that houses all of the DataElement objects I have the following to set the color.
Resources["EntryBoxHighlightBackground"] = Brushes.Yellow;
So, the first issue is that setting the Highlight property for the DataElement doesn't cause the textbox background to draw in yellow.
The other issue is that I realize that I am applying this style to all textboxes and I could have textboxes in other areas that are not actually contained within a DataElement, which may cause a binding issue.

Answer 1

Try converting your trigger to a DataTrigger, and add a binding that will look directly at the DataElement control, like so:
<DataTrigger Binding="{Binding Path=Highlight, RelativeSource={RelativeSource AncestorType={x:Type Elements:DataElement}}}" Value="True">
<Setter Property="Control.Background" Value="{DynamicResource EntryBoxHighlightBackground}"/>
</DataTrigger>