>Hi all,
>Your ideas can help me to choose method to write code for one time “undo & redo”. However, I still don’t understand how to undo and redo with more level, great than one level, and with many records in table with grid.
>Thanks
>Canh

Why don't you let the grid show a read/write cursor with data from your table, and then compare the cursor to the table after editing is finished? A undo will then be the same as skip the compare, a redo can be a compare to a second cursor. I hope you understand my idea.