Data Types in Visual Basic

The data type of a programming element refers to what kind of data it can hold and how it stores that data. Data types apply to all values that can be stored in computer memory or participate in the evaluation of an expression. Every variable, literal, constant, enumeration, property, procedure parameter, procedure argument, and procedure return value has a data type.

Declared Data Types

You define a programming element with a declaration statement, and you specify its data type with the As clause. The following table shows the statements you use to declare various elements.

Programming element Data type declaration
Variable In a Dim Statement

Dim amount As Double

Static yourName As String

Public billsPaid As Decimal = 0
Literal With a literal type character; see "Literal Type Characters" in Type Characters

Dim searchChar As Char = "." C
Constant In a Const Statement

Const modulus As Single = 4.17825F
Enumeration In an Enum Statement

Public Enum colors
Property In a Property Statement

Property region() As String
Procedure parameter In a Sub Statement, Function Statement, or Operator Statement

Sub addSale(ByVal amount As Double)
Procedure argument In the calling code; each argument is a programming element that has already been declared, or an expression containing declared elements

subString = Left( inputString , 5 )
Procedure return value In a Function Statement or Operator Statement

Function convert(ByVal b As Byte) As String

For a list of Visual Basic data types, see Data Types.

See Also

Type Characters
Elementary Data Types
Composite Data Types
Generic Types in Visual Basic
Value Types and Reference Types
Type Conversions in Visual Basic
Structures
Tuples
Troubleshooting Data Types
Data Types
Efficient Use of Data Types