void on_button_change_date_clicked(object o, EventArgs args)
{
DateTime dt = dateTime;
if(dt == DateTime.MinValue)
dt = DateTime.Now;
myDialogCalendar = new DialogCalendar(Catalog.GetString("Select of Birth"), dt);
myDialogCalendar.FakeButtonDateChanged.Clicked += new EventHandler(on_calendar_changed);
}