控制文件下载

Question

我正在使用TWebBrowser为我的程序构建一个更新程序。OnCreate TWebBrowser导航到给定的URL。要下载更新，用户必须单击链接。单击该链接时，将显示此弹出窗口：

​

​

所以我想知道是否有可能：

弹出并允许自动下载的

1. 旁路。
2. 设置了文件下载到.

的固定路径。

Answer 1

TWebBrowser不是您想要的，因为您没有显示活动的HTML。如前所述，还有许多其他选择。基本上，您需要一个HTTP请求。

下面是一个非常简单的使用WinInet的例子，它需要适应您的需要(线程、状态消息等等)。

function DownloadURL(inURL, destfile: string): boolean;
  var
    hOpen: HINTERNET;
    hFile: HINTERNET;
    myAgent: string;
    savefile: file;
    amount_read: integer;
   // the buffer size here generally reflects maximum MTU size.
   // for efficiency sake, you don't want to use much more than this.
    mybuffer: array[1..1460] of byte;
  begin
    Result := true;
    myAgent := 'Test downloader app';
   // other stuff in this call has to do with proxies, no way for me to test
    hOpen := InternetOpen(PChar(myAgent), 0, nil, nil, 0);
    if hOpen = nil then
      begin
        Result := false;
        exit;
      end;
    try
      hFile := InternetOpenURL(hOpen, PChar(inURL), nil, 0,
           INTERNET_FLAG_RELOAD or INTERNET_FLAG_DONT_CACHE, 0);
      if hFile = nil then
        begin
          Result := false;
          exit;
        end;
      try
        AssignFile(savefile, destfile);
        Rewrite(savefile, 1);
        InternetReadFile(hFile, @myBuffer, sizeof(mybuffer), amount_read);
        repeat
          Blockwrite(savefile, mybuffer, amount_read);
          InternetReadFile(hFile, @myBuffer, sizeof(mybuffer), amount_read);
        until amount_read = 0;
        CloseFile(savefile);
      finally
        InternetCloseHandle(hFile);
      end;
    finally
      InternetCloseHandle(hOpen);
    end;
  end;

procedure TForm1.Button1Click(Sender: TObject);
  // example usage.
  begin
    if SaveDialog1.Execute then
      begin
        if DownloadURL(Edit1.Text, SaveDialog1.FileName) then
          ShowMessage('file downloaded.')
        else
          ShowMessage('Error downloading file.');
      end;
  end;