I am sure this has been asked before, but I haven\'t had an easy time figuring out how to phrase the query.
I have this style;
Styles cannot be set from a Setter within the Style, because then essentially the first Style would never exist at all.
Since you're looking for a Validation style, I would recommend looking into Validation.ErrorTemplate
, although if that doesn't work you can change your trigger so it modifies specific properties such as BorderBrush instead of the Style property
i would think of using a Template with a TemplateTrigger and there you can change the style to what ever you like based on what ever condition