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VB & VBA in a Nutshell: The Language by Paul Lomax

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Dim Statement

Named Arguments

No

Syntax

Dim varname[([subscripts])] [As [New] type] [, 
    varname[([subscripts])] [As [New] type]] . . .

varname

Use: Required

Your chosen name for the variable.

subscripts

Use: Optional

Dimensions of an array variable.

New

Use: Optional

Keyword that creates an instance of an object.

type

Use: Optional

The data type of varname.

Description

Declares and allocates storage space in memory for variables. The Dim statement is used either at the start of a procedure or the start of a module to declare a variable of a particular data type.

Rules at a Glance

  • In addition to the Visual Basic data types listed in Chapter 3, type can be an Object, an object type, or a user-defined type. The default data type, when no type is explicitly declared, is Variant.

  • Variable-length strings are declared using the syntax:

    Dim variablename As String

    Fixed-length strings, on the other hand, are declared using the syntax:

    Dim variablename As String * length
  • You can declare multiple variables in a single Dim statement, but each variable you declare must use a separate As type clause.

  • Variables have the following values when they are first initialized with the Dim statement:

    Data Type Initial Value
    Numeric 0
    Variable-length string Zero-length string ("")
    Fixed-length string Padded with zeros
    Variant Empty
    Object Nothing
  • To use an object variable that has not been declared using the New keyword, the Set statement must assign an object to the variable before it can be used, as ...

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