Is Operator

Description

Compares two object expressions and returns -1 if they refer to the same object, 0 otherwise.

Syntax

objectExpression Is objectExpression

Comments

Is can also be used to test if an object variable has been Set to Nothing.

Example

This example displays a list of open files in the software application, VISIO. It uses the Is operator to determine whether VISIO is available. To see how this example works, you need to start VISIO and open one or more documents.

Sub main

   Dim visio as Object

   Dim doc as Object

   Dim msgtext as String

   Dim i as Integer, doccount as Integer

'Initialize Visio

   Set visio = GetObject(,"visio.application")	

' find Visio

   If (visio Is Nothing) then

      Msgbox "Couldn't find Visio!"

      Exit Sub

   End If

'Get # of open Visio files

   doccount = visio.documents.count	

'OLE call to Visio

   If doccount=0 then

      msgtext="No open Visio documents."

   Else

      msgtext="The open files are: " & Chr$(13)

      For i = 1 to doccount

         Set doc = visio.documents(i)	

' access Visio's document method

         msgtext=msgtext & Chr$(13)& doc.name

      Next i

   End If

   MsgBox msgtext

End Sub

See Also

Class List

CreateObject Function

GetObject Function

Nothing Function

Object Class

Typeof Function