Visual Basic 2005 in a Nutshell, Third Edition

IsDate Function | 345

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Reference

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IsArray Function

Class

Microsoft.VisualBasic.Information

Syntax

Dim result As Boolean = IsArray(varName)

varName (required; any variable)

A variable that may be an array

Description

The IsArray function indicates whether a variable is an array (True) or not (False).

Usage at a Glance

• Due to the nature of .NET objects, it is not always obvious that an Object vari-

able contains an array, since an entire array can be assigned to a simple

Object

variable. Calling array-specific functions like UBound or trying to access array

elements on a variable that is not an array will generate an error. If there is doubt

as to the nature of a variable, it should first be tested using the

IsArray function.

• An uninitialized array returns False. For example:

Dim unusedArray( ) As String

MsgBox(IsArray(unusedArray)) ' Displays "False"

• Array-like data structures, such as the Collection object, are not true arrays and

return

False when passed to the IsArray function.

Example

The following code displays “True,” even though the Object variable was not initially

declared as an array.

Dim multipleData( ) As Integer = {1, 2}

Dim singleData As Object

singleData = multipleData

MsgBox(IsArray(singleData)) ' Displays "True"

Version Differences

In VB 6, the IsArray function returns ...