MessageBox

var
    s:string='aaa';
    s1:string;
procedure TForm1.Button1Click(Sender: TObject);
begin
    s1:=Format('确定要删除 %s 这个文件夹吗?',[s]);
    if Application.MessageBox(PAnsiChar(s1), '提示', MB_YESNO +
      MB_ICONINFORMATION + MB_DEFBUTTON2 + MB_TOPMOST) = IDYES then
    begin

    end;
end;