perimeter block with area attribute

[Piron88]

Good morning, everyone. I've come across a question lately, apparently bigger than my knowledge. also looking on the web I couldn't find answer. I basically want to create a block from a polyline that defines me a perimeter (in my case the perimeter of a room ) and then inside this block add an attribute that contains the value of the area within the perimeter and that this area may vary to the range of the perimeter (e.g. in the case of rooms with different sizes ). In practice I would like to understand if it is possible with autocad to create a sort of block that according to its geometry, automatically defines me values as area and/or volume.
Does anyone know how to help me?
Thank you.

 

[Tristan]

You need to use data fields. explaining how to do in a post is a little complicated. . .
p.s. the volume extracts it only in case of solids; if you have only the contour I see hard