Delphi用TActionList实现下载文件的方法

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;beginProgressBar1.Max:= ProgressMax;ProgressBar1.Position:= Progress;end; procedure TForm1.Button1Click（Sender: TObject）;beginwith TDownloadURL.Create（self） dotry 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;