Thanks jmcilhinney.
Using that post i solved my problem.

And also fixed the issues u said in the replies of that post for non numerical data & backspace and decimal point.

but i have another doubt raised here.
Is it necessary to declare a row and add it like dday did.
i think not needed since i check each and every keychar of data entered in the dgv_keypress event(as of this Post).
Is thereany advantage of using like so.

And atlast i have not removed handler of dgv_keypresss since u said editingtextbox= nothing will do it. Am i right or need to remove handler