Как показать Open With диалог?

{ 
  This code displays the application/file "Open With" dialog 
  Passing the full file path and name as a parameter will cause the 
  dialog to display the line "Click the program you want to use to open 
  the file 'filename'". 
} 

uses 
  ShellApi; 

procedure OpenWith(FileName: string); 
begin 
  ShellExecute(Application.Handle, 'open', PChar('rundll32.exe'), 
    PChar('shell32.dll,OpenAs_RunDLL ' + FileName), nil, SW_SHOWNORMAL); 
end; 


procedure TForm1.Button1Click(Sender: TObject); 
begin 
  if Opendialog1.Execute then 
    OpenWith(Opendialog1.FileName); 
end;