Const

Declares constants for use in place of literal values.

Syntax:

[ attributes ]
[ Public | Private ] Const constname [ As type ] = expression

attributes: optional One or more of:
Description
Public: optional Keyword used at the module level to declare constants that are available to all procedures in all modules. Not allowed in procedures.
Private: optional Keyword used at the class or module level to declare constants that are available only within the class or module where the declaration is made. Not allowed in procedures.
constname: required Name of the constant; follows standard variable naming conventions.
type: optional The data type of the constant; may be Byte, Boolean, Integer, Long, Currency, Single, Double, Decimal, Date, String, or Variant. Use a separate As type clause for each constant being declared.
expression: required Literal, other constant, or any combination that includes all arithmetic or logical operators except Is.

Constants are private by default. Within procedures, constants are always private; their visibility can’t be changed. In standard modules, the Public keyword can change the default visibility of module-level constants. In class modules, constants are always private; the Public keyword has no effect.

To combine several constant declarations on the same line, separate each constant assignment with a comma. When constant declarations are combined in this way, the Public or Private keyword, if used, applies to all of them.

Variables, user-defined functions, and intrinsic Visual Basic functions (such as Chr) cannot be used in expressions assigned to constants.

Constants can make programs self-documenting and easy to modify. Unlike variables, constants can’t be inadvertently changed while the program is running.

When the constant type is not explicitly declared by using As type, the constant has the data type that is most appropriate for expression.

Constants declared in a Sub, Function, or Property procedure are local to that procedure. A constant declared outside a procedure is defined throughout the module in which it is declared. Constants can be used anywhere an expression is allowed.

Example

This example uses the Const statement to declare constants for use in place of literal values. Public constants are declared in the General section of a standard module, rather than a class module. Private constants are declared in the General section of any type of module.

' Constants are Private by default. 
Const MyVar = 459 
 
' Declare Public constant. 
Public Const MyString = "HELP" 
 
' Declare Private Integer constant. 
Private Const MyInt As Integer = 5 
 
' Declare multiple constants on same line. 
Const MyStr = "Hello", MyDouble As Double = 3.4567 