The Tree view (CV_TREE attribute) displays container items arranged hierarchically. CV_TREE is an attribute of the CNRINFO data structure's flWindowAttr field.

The leftmost items displayed in the Tree view are at the root level and are the same items displayed in all the other container views. Items that contain other items are called parent items. The items that a parent item contains are called child items and can be displayed only in the Tree view. Child items that contain other items serve a dual role: they are the children of their parent item, but they are parent items as well, with children of their own. For example, a parent item might be a book that contains individual child items for its chapters or a folder that contains several reports. The chapters or reports, in turn, could be parent items that contain their own children, such as the major sections of a chapter or report.

If the child items of a parent item are not displayed, the parent item can be Expanded to display them as a new branch in the Tree view. Once a parent item has been expanded, it can be Collapsed to remove its child items from the display.

You can use the cxTreeIndent and cxTreeLine fields of the CNRINFO data structure to specify the number of pels that a new branch is to be indented horizontally, and the width of the lines that are used to connect branches of the tree. These lines are displayed only if the CA_TREELINE attribute is specified in the flWindowAttr field.

The Tree view has three different types: Tree icon view, Tree text view, and Tree name view. If CV_TREE is specified, the Tree icon view is the default view. If neither CV_ICON, CV_TEXT, or CV_NAME are specified, CV_ICON is assumed.