Hi, Bui-

>How can i enable interactive with the combo in some rows and disable in other rows ?

In all honesty, you might have better luck changing your idea of using grids to edit data. Combos in grids are very slow, and rather difficult to control access to (as you are finding). This comes from many long and wasted hours fighting to get all kinds of fancy controls working in grids.

I found everything to be a thousand times simpler to use the grid to navigate around the cursor. When the user clicks on a row, I would display the current record in a set of controls outside the grid for actual editing. The form was faster, development was faster and less buggy.

That said, you probably want to do something in the cbo's When() method to control the access.

HTH