TdxCustomTreeView.OnExpanded Event
Allows you to respond to a node expansion.
Declaration
property OnExpanded: TdxTreeViewNodeEvent read; write;
Remarks
This event occurs every time a tree node is expanded.
You can handle the OnExpanding event to prohibit users from expanding a node.
Note
You can handle the control’s OnCollapsing and OnCollapsed events to track node collapse operations and customize their behavior.
The following OnExpanded event handler changes an image of the expanded node whose image index is 2 to an image with the index 1:
procedure TForm1.dxTreeViewControl1Expanded(Sender: TdxCustomTreeView;
ANode: TdxTreeViewNode);
begin
if ANode.ImageIndex = 2 then
ANode.ImageIndex := 1;
end;
Note
A tree node’s ExpandedImageIndex allows you to change the expanded node image without an OnExpanded event handler.
Refer to the TdxTreeViewNodeEvent type description for information on available options.
See Also