用URLDownloadToFile下载文件，如何用进度条跟踪下载进度(50分)

用URLDownloadToFile下载文件，如何用进度条跟踪下载进度

OnDownloadProgress

可有否具体的例子。

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtActns, ComCtrls;

type
TForm1 = class(TForm)
ProgressBar1: TProgressBar;
Label1: TLabel;
Button1: TButton;
procedure FormCreate(Sender: TObject);
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
DownLoadURL : TDownLoadURL;
procedure DownloadProgress(Sender: TDownLoadURL; Progress,
ProgressMax: Cardinal; StatusCode: TURLDownloadStatus; StatusText: String;
var Cancel: Boolean);
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.DownloadProgress(Sender: TDownLoadURL; Progress,
ProgressMax: Cardinal; StatusCode: TURLDownloadStatus;
StatusText: String; var Cancel: Boolean);
begin
Label1.Caption := StatusText;
ProgressBar1.Max := ProgressMax;
ProgressBar1.Position := Progress;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
DownLoadURL := TDownLoadURL.Create(self);
with DownLoadURL do
begin
FileName := 'c:/p.exe';
URL := 'http://www.teechart.net/files/vcl/public/TeeChartPro6/TeeChart601Delphi6_RTL3.EXE';
OnDownloadProgress := DownloadProgress;
end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
DownLoadURL.ExecuteTarget(DownLoadURL);
end;

end.

谢谢！