TdxCustomTreeView.OnCollapsed Event

Allows you to respond to node collapse operations.

Declaration

property OnCollapsed: TdxTreeViewNodeEvent read; write;

Remarks

This event occurs every time a tree node is collapsed.

You can handle the OnCollapsing event to prevent users from collapsing specific nodes.

Note

You can handle the control’s OnExpanding and OnExpanded events to track node expand operations and customize their behavior.

The following OnCollapsed event handler changes an image of the collapsed node whose image index is 1 to an image with the index 2:

Delphi

procedure TForm1.dxTreeViewControl1Collapsed(Sender: TdxCustomTreeView;
  ANode: TdxTreeViewNode);
begin
  if ANode.ImageIndex = 1 then
    ANode.ImageIndex := 2;
end;

C++

void __fastcall TForm1::dxTreeViewControl1Collapsed(TdxCustomTreeView *Sender,
  TdxTreeViewNode *ANode)
{
  if (ANode->ImageIndex == 1)
    ANode->ImageIndex = 2;
} 

Note

A tree node’s ExpandedImageIndex allows you to change the collapsed node image without an OnCollapsed event handler.

Refer to the TdxTreeViewNodeEvent type description for information on available options.