WPF Validation.ErrorTemplate Background Object

Question

I want to replace the normal behaviour of Validation.ErrorTemplate. I want to put a background border object (filled with red color) behind my own UserControl and then apply a simple color animation to blink it.

I tried this in my implicit control style:

<Style TargetType="{x:Type local:myControl}">
<Setter Property="Validation.ErrorTemplate">
    <Setter.Value>
         <ControlTemplate>
             <Border Name="ErrorBorder" CornerRadius"5" Background="Red">
                 <AdornedElementPlaceholder />
             </Border>
         </ControlTemplate>
    </Setter.Value>
</Setter>

<Style.Triggers>
    <Trigger Property="Validation.HasError" Value="True">
         <Setter Property="ToolTip" Value="{Binding 
                 RelativeSource={RelativeSource Self}, 
             Path=(Validation.Errors)[0].ErrorContent}" />
    </Trigger>
</Style.Triggers>
</Style>

Unfortunately the border object entirely overlays the control UI. The other question is: where is the right place to put a DoubleAnimation applied on Opacity to make my Background blinking? Wich property/event should I trigger? Should I use style or simply place it in the Border.Triggers?

Thank you

Answer 1

I'm pretty sure this isn't possible, adorners are always drawn on top of the adorned element.

See the Adorners Overview on MSDN

"An Adorner is a custom FrameworkElement that is bound to a UIElement. Adorners are rendered in an AdornerLayer, which is a rendering surface that is always on top of the adorned element or a collection of adorned elements"

You could probably get the same effect by adorning with a normal border that just borders the adorned element instead of trying to stick it behind the adorned element.