While the Tree class (see Tree Class) manages the relationship of the tree nodes, the TreeviewField object displays a visual representation of the hierarchical structure of a tree view. The TreeviewField class has a data type of TreeNode. The value of the field is the selected TreeNode. Initially, the tree is empty. You can use the AddNode method of the Tree class to insert nodes into the tree. If a user clicks on a new node, the value will change to the TreeNode clicked on. If 4GL code changes the value, that node will become the selected node.