インターフェース的クラス
Class cAbstractWindow

Public
  'ウィンドウプロシージャ
    Abstract Function wndProc(hWnd As HWND, message As DWord, wParam As WPARAM, lParam As LPARAM) As LRESULT

	'::::::::  ウィンドウ処理  ::::::::
Protected
  '作成された
    Abstract Sub opened(hWnd As HWND, pCreateStruct As *CREATESTRUCT)
  '閉じようとしている
    Abstract Function closing() As Long
  '閉じられた
    Abstract Sub closed()

End Class

'実装クラス
Class cWindow
　　　　Inherits cAbstractWindow

Public
  'ウィンドウプロシージャ
    Override Function wndProc(hWnd As HWND, message As DWord, wParam As WPARAM, lParam As LPARAM) As LRESULT

        Select Case message
            Case WM_CREATE
                opened(hWnd, lParam As *CREATESTRUCT)
            Case WM_CLOSE
                If (closing() = TRUE) then DestroyWindow(hWnd)
                return 0
            Case WM_DESTROY
                closed()

            （省略）
        End Select

        return _eventcallproc(hWnd, message, wParam, lParam)
    End Function


    '::::::::  ウィンドウ処理  ::::::::

Protected
  '作成された
    Override Sub opened(hWnd As HWND, pCreateStruct As *CREATESTRUCT)
    End Sub

  '閉じようとしている
    Override Function closing() As Long
        return TRUE
    End Function

  '閉じられた
    Override Sub closed()
    End Sub

End Class

グローバル領域
Dim wnd As cMainWindow( AddressOf(EventCall_MainWnd) )

Function MainWndProc(hWnd As HWND, dwMsg As DWord, wParam As WPARAM, lParam As LPARAM) As LRESULT
    return wnd.wndProc(hWnd, dwMsg, wParam, lParam)
    'MainWndProc=EventCall_MainWnd(hWnd,dwMsg,wParam,lParam)
End Function


'使用クラス
Class cMainWindow
　　　　Inherits cWindow

    '::::::::  ウィンドウ処理  ::::::::

Protected
  '作成された
    Override Sub opened(hWnd As HWND, pCreateStruct As *CREATESTRUCT)
        addItemEvent(ListView1)
    End Sub

End Class 

Dim a As Base
Dim b As Ext1
Dim c As Ext2

a.msg()
b.msg()
c.msg()


Class Base
Public
	Sub msg()
		doMsg()
	End Sub
Protected
	Virtual Sub doMsg()
		MessageBox(0, "スーパークラス", "Base", MB_OK)
	End Sub
End Class

Class Ext1
	Inherits Base
Protected
	Override Sub doMsg()
		MessageBox(0, "サブクラス1", "Ext1", MB_YESNO)
	End Sub
End Class

Class Ext2
	Inherits Ext1
Protected
	Override Sub doMsg()
		MessageBox(0, "サブクラス2", "Ext2", MB_YESNO)
	End Sub
End Class