Class Module

Related Topics

Group

Declaration

Description

A class module implements an object.

  • Has a set of Publicprocedures accessible from other macros and modules.
  • These public symbols are accessed by way of an object variable.
  • Has an optional set of Events that can be raised.
  • Public Consts, Types, arrays, fixed length strings are not allowed.
  • Has an optional Private Sub Class_Initialize which is called when an instance is created.
  • Has an optional Private Sub Class_Terminate which is called when an instance is destroyed.
  • A class module is similar to a object module except that no instance is automatically created.
  • To create an instance use: 
    Dim Obj As classname
Set Obj = New classname

Example

'A.WWB
'#Language "WWB-COM"
'#Uses "File.CLS"
Sub Main
    Dim File As New File
    File.Attach "C:\AUTOEXEC.BAT"
    Debug.Print File.ReadLine
End Sub
 
'File.CLS
'File|New Module|Class Module
'Edit|Properties|Name=File
'#Language "WWB-COM"
Option Explicit
Dim FN As Integer
Public Sub Attach(FileName As String)
    FN = FreeFile
    Open FileName For Input As #FN
End Sub
Public Sub Detach()
    If FN <> 0 Then Close #FN
    FN = 0
End Sub
Public Function ReadLine() As String
    Line Input '#'FN, ReadLine
End Function
 
Private Sub Class_Initialize()
    Debug.Print "Class_Initialize"
End Sub
 
Private Sub Class_Terminate()
    Debug.Print "Class_Terminate"
    Detach
End Sub