This event fires before the control enters edit mode. It allows you to prevent editing by setting the Cancel parameter to true, or to supply a list of choices for a combo list using the ComboList property, or an edit mask using the EditMask property.

If the choices or the mask are the same for a whole column, you may set them more efficiently using the ComboList and EditMask properties for the Column object. In this case, there's no need to handle the StartEdit event at all.

The grid also exposes a BeforeEdit event. The difference between the two is that BeforeEdit fires when the grid paints the cell that has the focus (so it can determine whether the cell has a drop-down button). BeforeEdit fires more often than StartEdit, and does not always indicate that the grid is actually entering edit mode.