How to make the default value of a type as Nothing?

Question

For example Dim aInt as Integer should have the value as nothing instead of 0.

Answer 1

In C# you need to use int? instead of int. Integers are value types and they can't have a null value.

With int? you can check the HasValue property to tell you it is is something other than null.

int? i = null;

i.HasValue // false;

to get the value use:

i.Value;

Answer 2

The only way to do that is to use Nullable<T> - i.e. (in C#):

int? aInt; // defaults to null

Regular integers have no concept of null/Nothing.

Answer 3

You'll have to use a nullable type. In vb.net - Nullable(Of Integer) (or Short, Byte)

Answer 4

Integer cannot be "nothing". You need to declare it as:

dim aInt as Nullable(of Integer)

Answer 5

As mentioned, use int? / Nullable(of Integer). Be careful not to overuse, though. I am working on a project where almost all valuetypes are declared as nullable / ?, and it is an absolute mess.

Answer 6

Other answers are right, you'll want to use a Nullable type. I wanted to precise the syntax for VB/C# and which version supports it:

VB9+ (Visual Studio 2008):

Dim aNullableInt As Integer?

VB8+ (Visual Studio 2005):

Dim aNullableInt As Nullable(Of Integer)

Whereas in C# 2.0 (Visual Studio 2005) you could already write it in both ways:

int? aNullableInt;
Nullable<int> aNullableInt;