Control metric to be queried with this message. This can be either of the
following:
VMA_ITEMSIZE
If this message attribute is set,
the width and height of each item (in pixels) are returned in the usItemWidth
and usItemHeight parameters, respectively.
VMA_ITEMSPACING
If this message attribute is set, the horizontal
and vertical spacing between items (in pixels) is returned in the usHorzItemSpacing
parameter and in the usVertItemSpacing parameter, respectively.
Amount of horizontal space allocated between each
value set item, in pixels. This number does not include the space needed
for selected-state and target emphasis, and for the selection cursor, because
the emphasis and cursor space is automatically allocated by the value set
control. The default space amount is 0.
Amount
of vertical space allocated between each value set item, in pixels. This
number does not include the space needed for selected-state and target emphasis,
and for the selection cursor, because the emphasis and cursor space is automatically
allocated by the value set control. The default space amount is 0.