Nullable types

The primitive types or value types are not nullable in C#. Consequently, there is always a requirement for the developer to make the type nullable, as a developer might need to identify whether the value is provided explicitly or not. The newest version of .NET provides nullable types:

Nullable<int> a = null;
int? b = a; //same as above

Both lines in the preceding example define the nullable variable, while the second line is just a shortcut of the first declaration. When the value is null, the HasValue property will return false. This will ensure that you can detect whether the variable is explicitly specified as a value or not.