How do you relate the grid row to your data (Key)?

In the example code your function is passing the column and row of the grid. This does not seem like a very reasonable way to perform updates to the database. You certainly can't expect that the key in the database is the same as your row number in the grid because you could delete various rows of data resulting in a non contiguous list of key on the table. How then do you suggest that the updates be performed to the database for the correct record?

exp_grid.setCellText(function(col, row){return col + "." + row});

exp_grid.setCellText(function(col, row){
var text0 = this.getCellText(0, row);
var text1 = this.getCellText(1, row);
return text0 + "-" + text1;
}, 2); // calculate column 2 from columns 0 and 1
i think you may be use getcelltext by you specific column and row paramiter for know key