Constraining Block Attributes

[Tom Mead]

Hi All, new user to these Autocad Forums so bare with me, Im trying to find out how to constrain a block attribute to the centre of a block.

 

I'll start of by creating a dynamic block and assign parameters and actions to it etc, with this i'll assign a VLOOKUP action which enables me to change the size/type of the block with one drop down list. This is all fine and well but when I assign an attribute to the block using the VLOOKUP string and try and constrain it to the centre of the block it never seems to work. The block size will change no problem but the attribute texx stays in the same place.

 

Would appreciate any help, thanks.