nullable object must have a value

Question

There is paradox in the exception description: Nullable object must have a value (?!)

This is the problem:

I have a DateTimeExtended class, tha

Answer 1

In this case oldDTE is null, so when you try to access oldDTE.Value the InvalidOperationException is thrown since there is no value. In your example you can simply do:

this.MyDateTime = newDT.MyDateTime;

Answer 2

Try dropping the .value

DateTimeExtended(DateTimeExtended myNewDT)
{
   this.MyDateTime = myNewDT.MyDateTime;
   this.otherdata = myNewDT.otherdata;
}