加快Delphi中状态栏的更新速度

Question

在Delphi中更新状态栏需要花费很长时间!

示例:我搜索文件并显示状态栏中找到和搜索的文件数:

OwnerForm.StatusBar1.SimpleText
     := Format('Searching (%d found in %d files) ...', [NumFound, Total]);

对于每200次更新状态栏,搜索大约增加1秒的时间.

有没有办法减少这种过多的开销,但仍然更新用户的状态？

Answer 1

不要快速更新状态栏.如果您经常更新它会对您的性能产​​生严重影响,用户将如何阅读状态？

此外,我运行了一个小测试,显示它在超过100毫秒的时间内更新状态栏1000次.这是我5岁便宜的家用电脑.

procedure TForm1.Button1Click(Sender: TObject);
var
  i: Integer;
  a: Cardinal;
begin
  a := GetTickCount;
  for i := 0 to 1000 do
  begin
    StatusBar1.SimpleText := IntToStr(i);
  end;
  ShowMessage(IntToStr(GetTickCount - a));
end;

[编辑]

替代方案:

  TForm1 = class(TForm)
    StatusBar1: TStatusBar;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    FLastUpdate: TDateTime;
  public
    procedure UpdateStatus(Status: string);
    procedure ForceStatus(Status: string);
  end;

procedure TForm1.ForceStatus(Status: string);
begin
  StatusBar1.SimpleText := Status;
  FLastUpdate := Now;
end;

procedure TForm1.UpdateStatus(Status: string);
begin
  if MilliSecondsBetween(Now, FLastUpdate) > 500 then
  begin
    StatusBar1.SimpleText := Status;

    FLastUpdate := Now;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  i: Integer;
  a: Cardinal;
begin
  a := GetTickCount;
  for i := 0 to 1000000 do
  begin
    // unimportant: progress
    UpdateStatus(IntToStr(i));
  end;
  // Important: final state
  ForceStatus(Format('Done in %d milliseconds', [GetTickCount - a]));
end;