IsReference Function

Returns a Boolean value that indicates whether an expression evaluates to a reference type.

Public Function IsReference(ByVal Expression As Object) As Boolean


  • Expression
    Required. Object expression.


IsReference returns True if Expression represents a reference type, such as a class instance, a String type, or an array of any type; otherwise, it returns False.

A reference type contains a pointer to data stored elsewhere in memory. A value type contains its own data.


This example uses the IsReference function to check if several variables refer to reference types.

Dim testArray(3) As Boolean 
Dim testString As String = "Test string" 
Dim testObject As Object = New Object()
Dim testNumber As Integer = 12
testArray(0) = IsReference(testArray)
testArray(1) = IsReference(testString)
testArray(2) = IsReference(testObject)
testArray(3) = IsReference(testNumber)

In the previous example, the first three calls to IsReference return True. The last call returns False, because Integer is a value type, not a reference type.


Namespace: Microsoft.VisualBasic

Module: Information

Assembly: Visual Basic Runtime Library (in Microsoft.VisualBasic.dll)

See Also


Value Types and Reference Types


IsArray Function (Visual Basic)

IsDate Function (Visual Basic)

IsDBNull Function

IsError Function

IsNothing Function

IsNumeric Function (Visual Basic)

Object Data Type

TypeName Function (Visual Basic)