Hello Paul.

I want to find out the value of the selected cell in a grid programmatically, and I can't find how to do it.

The grid only has an active (selected) cell when the grid has focus. You can refer to This.Value in the selected cell. Or from elsewhere in the grid, you can use code like this:

*** Find out which column is the active column
WITH This
  FOR EACH loColumn IN .Columns
    IF loColumn.ColumnOrder = .ActiveColumn
      luValue = EVAL( loColumn.ControlSource )
      EXIT
    ENDIF
  ENDFOR
ENDWITH

To access the data in the grid, you can just refere to its underlying RecordSOurce using Alias.Field.