Gridview with CheckBox

Question

Hi friends,
 i have a gridview in that there is a Column for Check box and others are for Entering data like MaterialDescription,Quantity,etc.,
i have query for how to get Checkbox in gridview & on selecting a particular check box in that row the Quanity textbox in Gridview should be enabled or Disabled on unselect.

pls reply how can it be done!!!

regards,
aamir