Download File with Progress Display

Hier ist ein Beispiel, wie man jeden Download als Fortschrittsanzeige in einer ProgressBar oder Gauge anzeigen lassen kann. Das Einzige, was bestimmt werden muss, ist die Dateiendung des Downloads.

uses ExtCtrls, UrlMon, ActiveX, Gauges

type
  cDownloadStatusCallback = class(TObject,IUnknown,IBindStatusCallback)
  private
    function QueryInterface(const IID: TGUID; out Obj): HResult; stdcall;
    function _AddRef: Integer; stdcall;
    function _Release: Integer; stdcall;
    function OnStartBinding(dwReserved: DWORD; pib: IBinding): HResult; stdcall;
    function GetPriority(out nPriority): HResult; stdcall;
    function OnLowResource(reserved: DWORD): HResult; stdcall;
    function OnProgress(ulProgress, ulProgressMax, ulStatusCode: ULONG; szStatusText: LPCWSTR): HResult; stdcall;
    function OnStopBinding(hresult: HResult; szError: LPCWSTR): HResult; stdcall;
    function GetBindInfo(out grfBINDF: DWORD; var bindinfo: TBindInfo): HResult; stdcall;
    function OnDataAvailable(grfBSCF: DWORD; dwSize: DWORD; formatetc: PFormatEtc; stgmed: PStgMedium): HResult; stdcall;
    function OnObjectAvailable(const iid: TGUID; punk: IUnknown): HResult; stdcall;
  end;
  
var
  Form1: TForm1;
  usercancel: Boolean = False;
  
//

function cDownloadStatusCallback._AddRef: Integer;
begin
  Result := 0;
end;

function cDownloadStatusCallback._Release: Integer;
begin
  Result := 0;
end;

function cDownloadStatusCallback.QueryInterface(const IID: TGUID; out Obj): HResult;
begin
  if(GetInterface(IID,Obj)) then
  begin
    Result := 0
  end else
  begin
    Result := E_NOINTERFACE;
  end;
end;

function cDownloadStatusCallback.OnStartBinding(dwReserved: DWORD; pib: IBinding): HResult;
begin
  Result := S_OK;
end;

function cDownloadStatusCallback.GetPriority(out nPriority): HResult;
begin
  Result := S_OK;
end;

function cDownloadStatusCallback.OnLowResource(reserved: DWORD): HResult;
begin
  Result := S_OK;
end;

function cDownloadStatusCallback.OnStopBinding(hresult: HResult; szError: LPCWSTR): HResult; stdcall;
begin
  Result := S_OK;
end;

function cDownloadStatusCallback.GetBindInfo(out grfBINDF: DWORD; var bindinfo: TBindInfo): HResult; stdcall;
begin
  Result := S_OK;
end;

function cDownloadStatusCallback.OnDataAvailable(grfBSCF: DWORD; dwSize: DWORD; formatetc: PFormatEtc; stgmed: PStgMedium): HResult;
begin
  Result := S_OK;
end;

function cDownloadStatusCallback.OnObjectAvailable(const iid: TGUID; punk: IUnknown): HResult; stdcall;
begin
  Result := S_OK;
end;

function cDownloadStatusCallback.OnProgress(ulProgress, ulProgressMax, ulStatusCode: ULONG; szStatusText: LPCWSTR): HResult;
begin
  case ulStatusCode of
    BINDSTATUS_FINDINGRESOURCE:
    begin
      Form1.Label1.Caption := 'Datei wurde gefunden...';
      if (usercancel) then
      begin
        Result := E_ABORT;
        exit;
      end;
    end;
    BINDSTATUS_CONNECTING:
    begin
      Form1.Label1.Caption := 'Es wird verbunden...';
      if (usercancel) then
      begin
        Result := E_ABORT;
        exit;
      end;
    end;
    BINDSTATUS_BEGINDOWNLOADDATA:
    begin
      Form1.Gauge1.Progress := 0;
      Form1.Label1.Caption := 'Der Download wurde gestartet...';
      if (UserCancel) then
      begin
        Result := E_ABORT;
        exit;
      end;
    end;
    BINDSTATUS_DOWNLOADINGDATA:
    begin
      Form1.Gauge1.Progress := MulDiv(ulProgress,100,ulProgressMax);
      Form1.Label1.Caption := 'Datei wird heruntergeladen...';
      if (UserCancel) then
      begin
        Result := E_ABORT; exit;
      end;
    end;
    BINDSTATUS_ENDDOWNLOADDATA:
    begin
      Form1.Label1.Caption := 'Download wurd beendet...';
    end;
  end;
  Application.ProcessMessages;

  Result := S_OK;
end;

Datei Download :

procedure TForm1.Button1Click(Sender: TObject);
var
  cDownStatus : cDownloadStatusCallback;
  status: integer;
begin
  cDownStatus := cDownloadStatusCallBack.Create;
    
   // DIES IST EIN TESTDOWNLOAD VON 100 MB 
   status := URLDownloadToFIle(nil,'https://ash-speed.hetzner.com/100MB.bin',
     'C:\temp.html',0,CDownStatus);  // HIER DER ZIELPFAD DES DOWNLOADS
    cDownStatus.Free;

   if (status <> 0) then
      Form1.Label1.Caption:='Es gab einen Fehler beim Herunterladen!';
end;