Delphi中的TActionList有個(gè)標(biāo)準(zhǔn)動(dòng)作TDownLoadURL，內(nèi)部是使用的URLDownloadToFile，它下載文件時(shí)會(huì)定時(shí)產(chǎn)生OnDownloadProgress 事件，這樣就可以用進(jìn)度條顯示。
本文講述了Delphi用TActionList實(shí)現(xiàn)下載文件的方法，實(shí)現(xiàn)代碼如下所示：
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:='//www.49028c.com/images/logo.gif'; FileName := 'logo.gif'; OnDownloadProgress := URL_OnDownloadProgress; ExecuteTarget(nil) ; finally Free; end; showMessage('OK'); ProgressBar1.Max := 0;end;新聞熱點(diǎn)
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