read only grid

The data in a grid is backed by the underlying data. A count() should help. Do you have any specific requirements?

Hi, If you are using query entity or queryRecordType for the data then you can set "fetchTotalCount" as true and from query output you can get total count.

This really isn't enough information for us to even hazard a guess at.  Can you tell us more about your requirement, what data you're starting with (and its source), what your general big-picture aim is, what you've already tried, and what particular trouble you're having?