Can DateTime be compared to null? Why or why not?

DateTime? ff=null; if (ff==null) { }

DateTime is a value type (structure) and has default value 1/1/0001 12:00:00 AM. we can compare it with null but can not hold null as it is value type unless made it as nullable datatype. DateTime? today = DateTime.Now; today=null;

DateTime is Rererence type . So We can Instantiated it by the new operator.Generaly the null value is not accespted by the type variable.But we can make it nullable in the example DateTime? dt = null; var d = dt?.ToString(); MessageBox.Show(d);

NO

It can be compared but result will be False

DateTime is a "Value Type". Basically a "value type" can't set to NULL. But by making them to "Nullable" type, We can set to null.

Yes, If declare DateTime variable as nullable like DateTime? then we can compare it with null.

And also to be noted if we compare with null it gives us false result because DateTime cannot understand what is null value and to which component of DateTime type it is actually being compared. So it is of no usage. I have given solution in my previous comment on how to deal with such situation.

DateTime is by default not a nullable type. So it can never store null value. Only if you declare DateTime nullable by notation DateTime? then it can hold null value. So I don't know what basically you want to perform. So suppose you want to do some assignment by checking whether the property has value or not for that you can use following. If you are using DateTime then DateTime dat = new DateTime(); if (dat==DateTime.MinValue) { //unassigned datetime } Or if you are using nullable DateTime then DateTime? dat = null; if (!dat.HasValue) { //unassigned } So answer to your question simply is that DateTime can never hold null value so cannot be compared. But there are ways by which we can understand if that particular property is having intended DateTime value or not.

DateTime CAN be compared to null; It cannot hold null value, thus the comparison will always be false.