type MyFTPThread = Class(TThread)
  private
    res: TStringList;
    Description, action: string;
    state: boolean;
    connected: boolean;
    max: Double;
    FTP: TIdFTP;

    procedure sync(descr: string; atend: boolean; ac: string);
    procedure updateVLC();
    procedure FTPWork(ASender: TObject; AWorkMode: TWorkMode; AWorkCount: Integer);
    procedure FTPWorkBegin(ASender: TObject; AWorkMode: TWorkMode; AWorkCountMax: Integer);

  protected
    procedure Execute; override;

  public
    upload, download, clear, abort: boolean;
     server, user, password: string;
      uploadname, downloadname: string;
    procedure initialize;
end;

implementation

uses OC_F1;

procedure MyFTPThread.Execute;
begin
  res := TStringList.Create;
  state := false;
  action := '-';
  initialize;
end;

procedure MyFTPThread.initialize;
var
  cnt: integer;
begin
  sync('Sequence started'#9#9' @ ' + TimeToStr(now), false, '_');

  FTP := TIdFTP.Create();
  FTP.Host := server;
  FTP.Username := user;
  FTP.Password := password;
  FTP.OnWork := FTPWork; // <-- Zuweisung der onWork-Prozedure auf meine eigene. Die Argumente müssen gleich sein!!!
  FTP.OnWorkBegin := FTPWorkBegin; // <-- Dasselbe für OnWorkBegin...

  FTP.Connect;

  if FTP.Connected then
    begin

      if download then
        begin
          ...
        end;

    if upload then
      begin
        ...
      end;

    if clear then
      begin
        ...
      end;
  end;

  FTP.Free;
end;

procedure MyFTPThread.updateVLC();
begin
  Form1.updateVLC(res, Description, state, action);
end;


procedure MyFTPThread.FTPWork(ASender: TObject; AWorkMode: TWorkMode;
  AWorkCount: Integer);
begin
  if max > 0 then
    begin
      Form1.updatePROG(AWorkCount, max); // Bei mir wird beim Download keine Maximalgröße der Datei übertragen. Deswegen setze ich bei
    end; // Downloads die Größe noch in der Downloadroutine mit FTP.GetSize (o.Ä.).

  if abort then
    begin
      FTP.Abort;
      download := false;
      upload := false;
      abort := false;
    end;
end;

procedure MyFTPThread.FTPWorkBegin(ASender: TObject; AWorkMode: TWorkMode;
  AWorkCountMax: Integer);
begin
if AWorkMode = wmWrite then // Wie oben beschrieben nur bei Uploads zu verwenden...
  max := AWorkCountMax;
end;

end.