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
Unless you use typeless programming, you must declare data types for all your programming elements. (For more information, see Typeless Programming in Visual Basic.)
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 (Visual Basic) 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 (Visual Basic) Dim searchChar As Char = "."C |
Constant |
In a Const Statement (Visual Basic) Const modulus As Single = 4.17825F |
Enumeration |
In an Enum Statement (Visual Basic) Public Enum colors |
Property |
In a Property Statement Property region() As String |
Procedure parameter |
In a Sub Statement (Visual Basic), Function Statement (Visual Basic), 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 (Visual Basic) or Operator Statement Function convert(ByVal b As Byte) As String |
See Also
Tasks
Troubleshooting Data Types (Visual Basic)
Reference
Data Type Summary (Visual Basic)
Concepts
Type Characters (Visual Basic)
Composite Data Types (Visual Basic)
Generic Types in Visual Basic (Visual Basic)
Value Types and Reference Types
Typeless Programming in Visual Basic
Other Resources
Elementary Data Types (Visual Basic)