Data Binding of a Tree UI Element

The Tree UI element displays hierarchical structures. Each Tree UI element contains a number of tree nodes either of the type TreeNodeType or TreeltemTyp . They describe which data is displayed below the top-level context node. The context node is bound by the Tree property dataSource . The only difference between the TreeNodeType element and the TreeltemType element is that the tree node type TreeNodeType can have children, whereas the type TreeltemType can display the leaves of a tree, but cannot have children.

The hierarchical structure of the tree UI element must be represented in the context. This is possible by specifying a certain number of levels in the context at design time. For example:  Customer  Order    OrderItems ..

Or you can create a recursive node in the context. In this case, a virtual node points to a parent node at design time. At runtime, a specific property of the context node allows to add non-singleton child nodes that need to be of the same type as the ones they are pointing to. In so doing, you specify - at design time - a context structure with recursive nodes that can have any number of levels at runtime.