C# Concept - Lazy properties

Overview

Lazy properties are a property design pattern, not a dedicated C# release feature. The pattern is usually implemented with ordinary properties plus deferred initialization.

Introduced In

This pattern has been possible since C# 1.0 (2002). The ??= operator used in many modern examples was introduced in C# 8.0 (2019).

Example

public class Person
{
  private string? _name;
  public string Name => _name ??= LoadName();

  private string LoadName() => "Lazy Loaded Name";
}

Notes

• Use Lazy<T> or locking when multiple threads can initialize the value.
• Reset the backing field when the cached value must be recomputed.