Nullable<T> struct - CSharp Language Basics

CSharp examples for Language Basics:Nullable

  1. HOME
  2. CSharp
  3. Language Basics
  4. Nullable

Introduction

T? translates into System.Nullable<T>, which is a lightweight immutable structure, having only two fields, to represent Value and HasValue.

The essence of System.Nullable<T> is very simple: 

public struct Nullable<T> where T : struct
{
  public T Value {get;}
  public bool HasValue {get;}
  public T GetValueOrDefault();
  public T GetValueOrDefault (T defaultValue);
  ...
}

The code: 

int? i = null;
Console.WriteLine (i == null);              // True

translates to: 

Nullable<int> i = new Nullable<int>();
Console.WriteLine (! i.HasValue);           // True

The default value of T? is null.


Related Tutorials