How to create a similar template like this for errors?

Question

I've seen in several sites where publish some images of their applications using a style for ErrorTemplate like this:

Do you know where can I find it?

Answer 1

This looks much like Adorner. The idea is to draw something above/near the control where its defined which is not also affected by transformations applied to scene.

For example you can define a Adorner in Style of your TextBox.

Something like this (a pseudocode):

<Style TargetType="{x:Type TextBox}">
     <Setter Property="Template">
                <Setter.Value>
                   <ControlTemplate TargetType="{x:Type ScrollViewer}">
                       ........
                       ........
                       <AdornerDecorator Grid.Column="0" Grid.Row="0">
                           .........
                           .........
                       </AdorenrDecorator>
                    </ControlTemplate>
                </Setter.Value>
     </Setter>
</Style>

A complete example (for ScrollViewer, but the ides is the same) can find here