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
Parameters
- Expression
Required. Object expression.
Remarks
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.
Example
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.
Requirements
Namespace: Microsoft.VisualBasic
Module: Information
Assembly: Visual Basic Runtime Library (in Microsoft.VisualBasic.dll)
See Also
Concepts
Value Types and Reference Types
Reference
IsArray Function (Visual Basic)
IsDate Function (Visual Basic)