How to pass null as DateTime value?

Question

In a database, there is a field that saves a closure date. This date can be NOT NULL only if the case has been closed. If the case is not closed, it has to be NULL. How can I pass null value to a DateTime object?

Tried this but it doesn't work.

DateTime closure= dateDatumIspisa.SelectedDate ?? null;
DateTime closure= dateDatumIspisa.SelectedDate ?? DateTime.Parse("");
DateTime closure= dateDatumIspisa.SelectedDate ?? DBNull.Value;
DateTime closure= dateDatumIspisa.SelectedDate ?? DateTime.Parse(DBNull.Value.ToString());

Also tried GetValueOrDefault() but it inserts DateTime.Min value, while I need this field left empty.

Any suggestions?

Answer 1

Just make closure a DateTime? instead of a DateTime. The whole point of Nullable<T> is to make a nullable type from a non-nullable one.

Now, you haven't shown the type of SelectedDate - but if it's already a DateTime? then you don't need to use ?? at all. Just:

DateTime? closure= dateDatumIspisa.SelectedDate;

How familiar are you with nullable value types in general? You might want to read up on the MSDN coverage of them.

Answer 2

Declare

DateTime ? closure = dateDatumIspisa.SelectedDate;

no need here to use the ?? in this line !