如何在DateTime为空（01/01/0001）时将DateTimePicker对象留空（选择日期），但在有值时填充？

I'm trying to get a DateTimePicker object to populate with the default text (Select a date) when it doesn't get any date back from the database. If there is a date in the database, the field will populate with that date. I'm trying to get a DateTimePicker object to po