virtualtreeview programmatically moving the selection bar (responding to down/up key)

Question

How to move the selection in the treeview, akin to dbgrid.next/dbgrid.previous?

I'm trying to move the selection bar in the VST when down/up key is pressed in a TEdit control.

This I have tried, works, but seems too verbose to me for a simple task:

procedure TfrmUserManager.edtTaskFilterKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
var
  Node: PVirtualNode;
begin
  if not Assigned(vstTasks.FocusedNode) then
    Node:= vstTasks.GetFirst
  else
    Node:= vstTasks.FocusedNode;
  if key = VK_DOWN then
    vstTasks.FocusedNode:= vstTasks.GetNextVisible(Node)
  else if key = VK_UP then
    vstTasks.FocusedNode:= vstTasks.GetPreviousVisible(Node);
  vstTasks.Selected[vstTasks.FocusedNode] := True;
  if key in [VK_DOWN,VK_UP] then key := 0;
end; 

Can this be simplified? TIA.