How to access existing data in DataGrid cell?

Hi,

Can anybody tell me how to access existing data in a DataGrid cell in labelFunction?

I am able to access the new data to be displayed in the cell.

What I want to do now is if the new value is less than the present value in the cell then show it in red else in green.

But, I am stuck on trying to read already existing value in the cell.

Can anybody help me please?