Filter behavior

Hi,

I'm trying to use the autocompletebox in a way so I can use it to visualize filters in a search. In order to do that, I want to add a tag to the textblock element in order to later on identify the category of the text in the textblock element. I tried to play with the createtextblock event and formatting, but it doesn't quite work out. Can you give me some guideance? 

Thanks in advance!