A Programmer's Guide to C# 5.0, 4th Edition

CHAPTER 27

Nullable Types

It is sometimes useful to know whether a value has been defined. This concept is present for reference types (classes) by using the null value. Nullable types are used to support this concept with value types (structs).

A Simple Example

Assume you are writing a customer-tracking system and have created the following class:

class Customer{    public Customer(string name, string company)    {       Name = name;       Company = company;    }    public string Name { get; set; }    public string Company { get; set; }    public string City { get; set; }    public int YearOfBirth { get; set; }}

In addition to the name and company ...