TTreeNode.HasChildren does'nt work when node is collapsed

I've created a function to save a TTreeView to a file. The problem is just that if a node is collapsed, the code does'nt get the childs.

(Using Delphi7 Enterprise)

The code so far:


  if Node.HasChildren then    //Problem occures here (I think)
    begin
      TN := Node.getFirstChild;
      TLR := Result;
      repeat
        TLR := WriteNode(TN, TLR);
        T := T + IntToStr(TLR.Number) + '&';

        TN := Node.GetNextChild(TN);
      until TN = nil;
      Ini.WriteString(S, 'SubNodes', T);
    end
  else
    begin
      Ini.WriteString(S, 'SubNodes', 'NONE');
    end;