[RESOLVED] how to edit a cell and validate it in Datagrid view?

[VBNewBiz]

Hi All,
I am using a datagrid view.i want to edit the second column of the grid (as in the image below)and validate it ,to get data from database.
Which event of datagridview has to be used?I have used _cellbeginedit,_cellvalidating..but no use..
Any help is appreciated.