Null Value
Learn what the null value is.
We'll cover the following...
The null
and reference types
In C#, we have a special value called null
. This value represents the absence of value and is the default for reference-type variables.
string name = null;
The null
value means that a variable doesn’t point to anything in memory. Because we’re dealing with references, we can’t assign null
to a value-type variable, such as int
.
If we try to access a variable that doesn’t point to anything, we get a NullReferenceException
:
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using System;namespace NullValue{class Program{static void Main(string[] args){string name = null;// name is null. Accessing its members and methods// will yield an errorstring nameInUpperCase = name.ToUpper();Console.WriteLine(nameInUpperCase);}}}
The null
and value types
Unlike reference types, value-type variables can’t be assigned the null
value directly. However, it’s quite common to potentially need a value-type to be null
. For instance, if we’re fetching some ...