Container items in the Tree text view (CV_TREE | CV_TEXT) are displayed as text strings. In both views, the container control does not limit the number of lines of text or the number of characters in each line.
In the Tree icon and Tree text views, a parent item is expanded by selecting the Collapsed icon/bit map, which is displayed to the left of the parent item.
The Collapsed icon/bit map should contain some visible indication that the item can be expanded. The default Collapsed bit map that is provided by the container control uses a plus sign (+) to indicate that more items, the children of this parent, can be added to the view.
When the child items of a parent item are displayed, the Collapsed icon/bit map to the left of that parent item changes to an Expanded icon/bit map. Just as the Collapsed icon/bit map provides a visible indication that an item can be expanded, so should the Expanded icon/bit map indicate that an item can be collapsed. The default Expanded bit map provided by the container control uses a minus sign (-) to indicate that the child items of this parent can be subtracted from the view. If any of the child items have children of their own, a Collapsed or Expanded icon/bit map is displayed to their immediate left as well.
To display your own Collapsed and Expanded icons or bit maps, specify their handles by using the hptrCollapsed and hptrExpanded fields of the CNRINFO data structure for icons, and the hbmCollapsed and hbmExpanded fields for bit maps. Also, you can use the slTreeBitmapOrIcon field to specify the size, in pels, of these Collapsed and Expanded icons and bit maps.