Ouvrir la boite de dialogue 'Ouvrir avec ...'

//Thanks to Andreas Kosch for Help
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
begin
OpenWith(Opendialog1.FileName);
end;
end;