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:

Delphi

procedure TForm1.dxTreeViewControl1Expanded(Sender: TdxCustomTreeView;
  ANode: TdxTreeViewNode);
begin
  if ANode.ImageIndex = 2 then
    ANode.ImageIndex := 1;
end;

C++

void __fastcall TForm1::dxTreeViewControl1Expanded(TdxCustomTreeView *Sender,
  TdxTreeViewNode *ANode)
{
  if (ANode->ImageIndex == 2)
    ANode->ImageIndex = 1;
} 

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.