What are Enumerations in VB.NET and how are they used?

An Enumeration (or Enum) in VB.NET is a special value type consisting of a number of named integer constants. For example:

  Enum Colors

     Red = 1

     Green = 2

     Blue = 3

  End Enum 

  Dim c As Colors = Colors.Red

If you don't specify the values of the constants, then the first one is taken to have a value of 0 and the remainder then add 1 to the previous value. For example:

  Enum Cars

    Toyota

    Kia

    Ford

  End Enum

Here Toyota has a value of 0, Kia 1 and Ford 2. 

The underlying base type of an Enum is Integer unless you specify some other integral type when you declare it:

  Enum Companies As Byte

    Microsoft = 1

    Apple = 2

  End Enum

Although Enums are value types, they derive from a special class called System.Enum which contains a number of Shared methods (see  http://msdn.microsoft.com/en-us/library/system.enum.aspx).        

Enums are useful because they enable you to give a group of related integer constants meaningful names - you don't have to remember the values themselves.