System.DateTime? vs System.DateTime

Question

I was writing to some code where I needed to read the date value from a Calendar control in my page (Ajax toolkit: calendar extender).

The code below:

Answer 1

The Calendar control returns a Nullable (shorthand in C# is DateTime?) in its SelectedDate Property, since DateTime is a struct. The null value allows the Control to have a "no date selected" state. Thus, you'll need to check if the nullable has a value before you can use it.

var nullable = myCalendarExtender.SelectedDate;
var newSelectedDate = (nullable.HasValue) ? nullable.Value : SomeDefaultValue;

EDIT: Even more concise, thanks to Josh's comment:

var newSelectedDate = myCalendarExtender.SelectedDate ?? SomeDefaultValue;

I like it!