Use the ExpandOnDblClk property to specify whether the control expands or collapses a node when user dbl clicks a node. Use the ExpandOnKeys property to allow users expand or collapse the nodes using the keyboard. 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.

Use the Expanded property to expand or collapse a node. Use the ExpandAll method to expand all nodes in the control. Use the CollapseAll method to collapse all nodes in the control. Use the ExpandAll method to expand all child nodes. Use the CollapseAll method to collapse all child nodes.