Use the TreeNodeStyle.NodeSpacing property to control the amount of vertical spacing between a node that the System.Web.UI.WebControls.TreeNodeStyle is applied to and its adjacent nodes at the same level. This space is inserted between the upper edge of the current node and the lower edge of the previous node, as well as between the lower edge of the current node and upper edge of the next node. The upper space is not rendered for the first node in the System.Web.UI.WebControls.TreeView control, because this would leave an unnecessary gap at the top of the control.

The TreeNodeStyle.NodeSpacing and TreeNodeStyle.ChildNodesPadding properties are applied independently. Whether or not the node is expanded does not affect the node spacing.

The value of this property is stored in view state.