.NET Framework also provides the ?? operator, called the null-coalescing operator, and its primary use is to define a default value for a nullable value types as well as reference types. It returns the left-hand operand if it is not null; otherwise it returns the right operand.
As an example, if the following code is run, the intValue will be 1, since nullInt is null.
Nullable<int> nullInt = null;
int intValue = nullInt ?? 1;