C# in Depth

Chapter 4. Saying nothing with nullable types

This chapter covers

• Motivation for null values

• Framework and runtime support

• Language support in C# 2

• Patterns using nullable types

Nullity is a concept that has provoked a certain amount of debate over the years. Is a null reference a value, or the absence of a value? Is “nothing” a “something”? In this chapter, I’ll try to stay more practical than philosophical. First we’ll look at why there’s a problem in the first place—why you can’t set a value type variable to null in C# 1 and what the traditional alternatives have been. After that I’ll introduce you to our knight in shining armor—System.Nullable<T>—before we see how C# 2 makes working with nullable types a bit simpler and more compact. Like generics, ...