Nullable DateTimes and the AddDays() extension

Question

I have a DateTime variable that can either be null or a Datetime. I figured a nullable DateTime type would work, but I am getting an error telling me that said

Answer 1

There are multiple ways to resolve this error.

1. Use Convert.ToDateTime() method which handles null datetime values.

   Convert.ToDateTime(lastInvite).AddDays(7);

2. Use Value property

   lastInvite.Value.AddDays(7)

3. Use GetValueOrDefault() method

   lastInvite.GetValueOrDefault().AddDays(7)