Expanding and Collapsing Nodes

TreeView allows end-users to hide/show a node children. End-users can expand or collapse nodes by double-clicking them. It is also possible to expand/collapse nodes by clicking expand buttons. The visibility of these buttons can be controlled by using the TreeViewSettings.ShowExpandButtons property.

TreeView provides the server and client API, which expand and collapse nodes in code. You can perform the following actions with a node.

To impact a particular node: Client Members Server Members
To expand/collapse a particular node ASPxClientTreeViewNode.SetExpanded TreeViewNode.Expanded (via MVCxTreeViewNode.Expanded)
To determine the node's expansion state ASPxClientTreeViewNode.GetExpanded TreeViewNode.Expanded (via MVCxTreeViewNode.Expanded)
To expand TreeView down to the specified node ASPxTreeView.ExpandToNode (via MVCxTreeView.ExpandToNode)
To impact all nodes: Client Members Server Members
To expand all nodes ASPxClientTreeView.ExpandAll (via MVCxClientTreeView.ExpandAll) ASPxTreeView.ExpandAll (via MVCxTreeView.ExpandAll)
To collapse all nodes ASPxClientTreeView.CollapseAll (via MVCxClientTreeView.CollapseAll) ASPxTreeView.CollapseAll (via MVCxTreeView.CollapseAll)
To expand all nodes to the defined depth ASPxTreeView.ExpandToDepth (via MVCxTreeView.ExpandToDepth)
To respond to expanding/collapsing nodes: Client Events Server Events
Before action ASPxClientTreeView.ExpandedChanging (via MVCxClientTreeView.ExpandedChanging) ASPxTreeView.ExpandedChanging (via MVCxTreeView.ExpandedChanging)
After action ASPxClientTreeView.ExpandedChanged (via MVCxClientTreeView.ExpandedChanged) ASPxTreeView.ExpandedChanged (via MVCxTreeView.ExpandedChanged)

TreeView - Expanding and Collapsing Nodes