[roamer]

Взято из DRKB:

Код:

procedure TForm1.TreeView1DragDrop(Sender, Source: TObject; X, Y: Integer);
var
  Node, SelNode: TTreeNode;
begin
  Node := TreeView1.GetNodeAt(X, Y);
  if Node = nil then
    Exit;
  SelNode := TreeView1.Selected;
  SelNode.MoveTo(Node, naAddChild);
end;


procedure TForm1.TreeView1DragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);
var
  Node, SelNode: TTreeNode;
begin
  Node := TreeView1.GetNodeAt(x, y);
// находим узел-приемник
  Accept := (Sender = Source) and (Node <> nil);
  if not Accept then
    Exit;
  SelNode := Treeview1.Selected;
  while (Node.Parent <> nil) and (Node <> SelNode) do
  begin
    Node := Node.Parent;
    if Node = SelNode then
      Accept := False;
  end;
end;