MWAPI - TOPSHOW

Draft MDC Standard

TOPSHOW specifies which choice is displayed at the top of the visible area of certain gadget types that display choices, or which non-header row is displayed at the top of the scrolling region of a table gadget. If the user scrolls the choices or table rows, the value of TOPSHOW changes.

If the application assigns a value to TOPSHOW, the list of choices or table rows may scroll.

If the value assigned to TOPSHOW exactly matches an item subscript specified for a choice or an ritem subscript specified for a table non-header row, the choice or row identified by that subscript is displayed at the top of the visible area or scrolling region.

If the application assigns a value to TOPSHOW which does not exactly match an item subscript or an ritem subscript for a non-header row specified for the gadget, the choice row identified by the first item or the first non-header row identified by an ritem subscript that follows (in the collation sequence of ^$WINDOW) the specified TOPSHOW value is displayed at the top of the visible area or scrolling region. TOPSHOW is then set to that subscript value.

If the application assigns a value to TOPSHOW which does not exactly match an item or ritem subscript specified for the gadget, and which is not followed (in the collation sequence of ^$WINDOW) by any item or by any ritem subscript for a non-header row specified for the gadget, the list of choices or rows scrolls (if necessary) so that the last choice in the list or the last row in the table is displayed in the visible area. TOPSHOW is then set to the item or ritem displayed at the top of the visible area.

If the aggregate height of choices or rows is at least great enough to fill the display area and the value assigned to TOPSHOW would cause the display area to be only partially filled, the underlying windowing platform or the MWAPI implementation may scroll the list to fill the visible area. TOPSHOW is then set to the item or ritem value for the choice or non-header row displayed at the top of the visible area.