Use the Expanded property to expand or collapse a node. The control fires the BeforeExpandNode event before expanding or collapsing a node.  The control fires the AfterExpandNode event to notify your application that a node is expanded or collapsed. Use the ExpandAll method to expand all child nodes. Use the CollapseAll method to collapse all child nodes. Use the ExpandAll method to expand all nodes in the control. Use the CollapseAll method to collapse all nodes in the control. Use the HasChilds property to specify whether the node displays the +/- sign to build your virtual tree. Use the ExpandOnDblClk property to let users expand or collapse nodes when double clicking a node. Use the ExpandOnKeys property to allow users expand or collapse the nodes using the keyboard. Use the ExpandButtons property to assign a different appearance for expanding/collapsing buttons. The ExpandOnSearch property specifies whether the control expands nodes when incremental searching is on ( AutoSearch property is different than 0 ) and user types characters when the control has the focus.