[hitman797]

System.SysUtils and System.IOUtils Unite:

procedure TForm8.Button1Click(Sender: TObject);
var
  i: Integer;
  hFileName: String;
  hDirArray, hFileArray: TStringDynArray;
begin
  ListBox1.Items.Clear;
  ListBox1.BeginUpdate;
  hFileName := 'C:\Windows';
  ListBox1.Items.Add(ExtractFileName(hFileName));
  hDirArray := TDirectory.GetDirectories(hFileName);
  for hFileName in hDirArray do
  begin
    ListBox1.Items.Add(ExtractFileName(hFileName));
  end;
{  hFileArray := TDirectory.GetFiles(hFileName);
  for hFileName in hFileArray do
  begin
    ListBox1.Items.Add(ExtractFileName(hFileName));
  end;  }
  ListBox1.EndUpdate;
end;