how to take automatic height to pannel?

hi,
i take one pannel in that pannel i place gridview, i take pannel height = 200px and width = 500px; and bottom of gridview some controls is there, my problem is if in gridview contain 2 or 3 rows that time some gap available between gridview and controls. (i.e., pannel height)
           in my project need controls in bottom of gridview, in question is any chance to take automatic height to the pannel, my aim is pannel take some height(we not give) after achieve that height scrollbars are appear.
please give a solution.
Thanks.