Delphi中的TActionList有个标准动作TDownLoadURL，内部是使用的URLDownloadToFile，它下载文件时会定时产生OnDownloadProgress 事件，这样就可以用进度条显示。

本文讲述了Delphi用TActionList实现下载文件的方法，实现代码如下所示：

uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, ExtActns, ActnList, StdCtrls, ComCtrls; type TForm1 = class(TForm) Button1: TButton; ActionList1: TActionList; ProgressBar1: TProgressBar; procedure Button1Click(Sender: TObject); private { Private declarations } procedure URL_OnDownloadProgress (Sender: TDownLoadURL; Progress, ProgressMax: Cardinal; StatusCode: TURLDownloadStatus; StatusText: String; var Cancel: Boolean) ; public { Public declarations } end; var Form1: TForm1; implementation {$R *.dfm} procedure Tform1.URL_OnDownloadProgress; begin ProgressBar1.Max:= ProgressMax; ProgressBar1.Position:= Progress; end; procedure TForm1.Button1Click(Sender: TObject); begin with TDownloadURL.Create(self) do try URL:='http://www.jb51.net/images/logo.gif'; FileName := 'logo.gif'; OnDownloadProgress := URL_OnDownloadProgress; ExecuteTarget(nil) ; finally Free; end; showMessage('OK'); ProgressBar1.Max := 0; end;