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Delphi用TActionList下载文件

2024-07-07 08:31:08   231人阅读

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：

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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://static.cnblogs.com/images/logo_small.gif‘;
     FileName := ‘logo.jpg‘;
     OnDownloadProgress := URL_OnDownloadProgress;
     ExecuteTarget(nil) ;
   finally
     Free;
   end;
   showMessage(‘OK‘);
   ProgressBar1.Max := 0;
end;

　　


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