C# Language Null-conditional Operators Null-Conditional Operator
Example
The ?. operator is syntactic sugar to avoid verbose null checks. It's also known as the Safe navigation operator.
Class used in the following example:
public class Person
{
public int Age { get; set; }
public string Name { get; set; }
public Person Spouse { get; set; }
}
If an object is potentially null (such as a function that returns a reference type) the object must first be checked for null to prevent a possible NullReferenceException. Without the null-conditional operator, this would look like:
Person person = GetPerson();
int? age = null;
if (person != null)
age = person.Age;
The same example using the null-conditional operator:
Person person = GetPerson();
var age = person?.Age; // 'age' will be of type 'int?', even if 'person' is not null
Chaining the Operator
The null-conditional operator can be combined on the members and sub-members of an object.
// Will be null if either `person` or `person.Spouse` are null
int? spouseAge = person?.Spouse?.Age;
Combining with the Null-Coalescing Operator
The null-conditional operator can be combined with the null-coalescing operator to provide a default value:
// spouseDisplayName will be "N/A" if person, Spouse, or Name is null
var spouseDisplayName = person?.Spouse?.Name ?? "N/A";
