VBScript in a Nutshell, 2nd Edition

Name

TypeName Function

Syntax

TypeName(varname)

varname

Use: Required

Data Type: Any

The name of a variable.

Return Value

A String.

Description

Returns a string containing the name of the data type of a variable.

Rules at a Glance

• TypeName returns the variant’s data type. If the variant has not been assigned a value, TypeName returns Empty. Therefore, TypeName never actually returns the string “Variant.”

• The following table describes the possible return values and their meaning:

Return value	Underlying data type
Boolean	Boolean
Byte	Byte
classname	An object variable of type classname
Currency	Currency
Date	Date
Decimal	Decimal
Double	Double-precision floating-point number
Empty	Uninitialized variable
Error	A missing argument error
Integer	Integer
Long	Long integer
Nothing	A variable of type Object that is not set to a valid object
Null	No valid data
Object	A generic object
Single	Single-precision floating-point number
String	String
Unknown	An object whose type is unknown
Variant( )	An array

VBA/VBScript Differences

• In VBA, the data type of a strongly typed variable can be ascertained earlier than the data type of a VBScript variable. For instance, in VBA, the code fragment:

  Dim lNumber As Long
  MsgBox TypeName(lNumber)

  indicates that lNumber is a long. The equivalent VBScript code fragment:

  Dim lNumber
  MsgBox TypeName(lNumber)

  indicates that lNumber is Empty, since it hasn’t yet been assigned a value and therefore VBScript cannot determine its data type. (Note that, in VBA, if lNumber is defined as a variant, the behavior of the ...