From SQP VBScript reference

本文介绍VBScript中如何定义类与常量,包括ClassStatement用于声明类及其成员,ConstStatement用于声明常量,并解释了其使用方法及注意事项。

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Class Statement

See Also

Dim Statement | Function Statement | Private Statement | Property Get Statement | Property Let Statement | Property Set Statement | Public Statement | Set Statement | Sub Statement

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Requirements

Version 5

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Declares the name of a class, as well as a definition of the variables, properties, and methods that comprise the class.

Class name
   statements
End Class 
Arguments
name
Required. Name of the Class; follows standard variable naming conventions.
statements
Required. One or more statements that define the variables, properties, and methods of the Class.
Remarks

Within a Class block, members are declared as either Private or Public using the appropriate declaration statements. Anything declared as Private is visible only within the Class block. Anything declared as Public is visible within the Class block, as well as by code outside the Class block. Anything not explicitly declared as either Private or Public is Public by default. Procedures (either Sub or Function) declared Public within the class block become methods of the class. Public variables serve as properties of the class, as do properties explicitly declared using Property Get, Property Let, and Property Set. Default properties and methods for the class are specified in their declarations using the Default keyword. See the individual declaration statement topics for information on how this keyword is used.

 

Const Statement

See Also

Dim Statement | Function Statement | Private Statement | Public Statement | Sub Statement

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Requirements

Version 5

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Declares constants for use in place of literal values.

[Public | Private] Const constname = expression
Arguments
Public
Optional. Keyword used at script level to declare constants that are available to all procedures in all scripts. Not allowed in procedures.
Private
Optional. Keyword used at script level to declare constants that are available only within the script where the declaration is made. Not allowed in procedures.
constname
Required. Name of the constant; follows standard variable naming conventions.
expression
Required. Literal or other constant, or any combination that includes all arithmetic or logical operators except Is.
Remarks

Constants are public by default. Within procedures, constants are always private; their visibility can't be changed. Within a script, the default visibility of a script-level constant can be changed using the Private keyword.

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.

You can't use variables, user-defined functions, or intrinsic VBScript functions (such as Chr) in constant declarations. By definition, they can't be constants. You also can't create a constant from any expression that involves an operator, that is, only simple constants are allowed. Constants declared in a Sub or Function procedure are local to that procedure. A constant declared outside a procedure is defined throughout the script in which it is declared. You can use constants anywhere you can use an expression. The following code illustrates the use of the Const statement:

Const MyVar = 459   ' Constants are Public by default.
Private Const MyString = "HELP"   ' Declare Private constant.
Const MyStr = "Hello", MyNumber = 3.4567   ' Declare multiple constants on same line.

Note   Constants can make your scripts self-documenting and easy to modify. Unlike variables, constants cannot be inadvertently changed while your script is running.

 

Dim Statement

See Also

Private Statement | Public Statement | ReDim Statement | Set Statement

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Requirements

Version 1

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Declares variables and allocates storage space.

Dim varname[([subscripts])][, varname[([subscripts])]] . . .
Arguments
varname
Name of the variable; follows standard variable naming conventions.
subscripts
Dimensions of an array variable; up to 60 multiple dimensions may be declared. The subscripts argument uses the following syntax:

upperbound [,upperbound] . . .

The lower bound of an array is always zero.

Remarks

Variables declared with Dim at the script level are available to all procedures within the script. At the procedure level, variables are available only within the procedure.

You can also use the Dim statement with empty parentheses to declare a dynamic array. After declaring a dynamic array, use the ReDim statement within a procedure to define the number of dimensions and elements in the array. If you try to redeclare a dimension for an array variable whose size was explicitly specified in a Dim statement, an error occurs.

Note   When you use the Dim statement in a procedure, you generally put the Dim statement at the beginning of the procedure.

The following examples illustrate the use of the Dim statement:

Dim Names(9)       ' Declare an array with 10 elements.
Dim Names()        ' Declare a dynamic array.
Dim MyVar, MyNum   ' Declare two variables.
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