Nullable value types can hold either a value or null. The value held in the nullable type can be accessed with the Value property, but .Value throws an InvalidOperationException when the value is null. To avoid the exception, a nullable type should always be tested before .Value is accessed.

Noncompliant Code Example

int? nullable = null;
...
UseValue(nullable.Value); // Noncompliant

Compliant Solution

int? nullable = null;
...
if (nullable.HasValue)
{
  UseValue(nullable.Value);
}

or

int? nullable = null;
...
if (nullable != null)
{
  UseValue(nullable.Value);
}

See

• MITRE, CWE-476 - NULL Pointer Dereference