Delphi FMX TListBox 处理大型列表时速度较慢

Question

我正在将 2,000 个名称加载到 FMX TListBox 中，但花费的时间太长（例如 35 秒或更长）。

这是测试代码：

procedure TDocWindow.DEBUGAddLotsOfStringsToList;
var
  theTimeAtStart: Integer;
  J: Integer;

begin
  ListBox1.Clear;

  theTimeAtStart := TThread.GetTickCount;

  for J := 1 to 2200 do
    begin
      ListBox1.Items.Add(j.toString);
    end;

  ShowMessage('There were ' + J.ToString + ' strings added to the list in ' + (TThread.GetTickCount - theTimeAtStart).ToString + ' milliseconds.');
end;

TListBox 是否有什么东西使得它对于几千个字符串来说太慢了？

Answer 1

使用BeginUpdate后，EndUpdate我的系统运行时间从 25 秒减少到约 125 毫秒。

procedure TForm1.Button1Click(Sender: TObject);
var
  theTimeAtStart: Integer;
  J: Integer;
begin
  theTimeAtStart := TThread.GetTickCount;

  ListBox1.Items.BeginUpdate;

  try
    ListBox1.Clear;

    for J := 1 to 2200 do
    begin
      ListBox1.Items.Add(j.ToString());
    end;
  finally
    ListBox1.Items.EndUpdate;
  end;
  ShowMessage('There were ' + J.ToString + ' strings added to the list in ' + (TThread.GetTickCount - theTimeAtStart).ToString + ' milliseconds.');
end;