The WTreeNode class is a flexible building blocks for creating a hierarchical tree. Through specialization, the tree contents can be customized to contain abitrary widgets.

The tree supports several options for progressively loading the tree contents, and all expand/collapse behaviour is optimized to client-side when JavaScript is available (although the entire tree is implemented purely in C++).

The WTree class manages a hierarchy of WTreeNode nodes, and provides support for single or multiple selection.

This example also uses a small class called WIconPair, which provides an easy interface to showing one of two icons.

The flexibility of the WTree class comes at a cost (in terms of client-side and server-side resources). In many cases, the WTreeView class may be more suitable for displaying large data models, using a MVC (Model-View-Controller) approach.

Related topics: WTreeView.