outlook防2B宏

Private Sub Application_ItemSend(ByVal Item As Object, Cancel As Boolean)
    Dim lngres As Long
    If Item.Subject = "" Then
        Application.Explorers(1).Activate
        lngres = MsgBox("没有主题？？？", _
        vbYesNo + vbDefaultButton2 + vbQuestion, "提示")
        If lngres = vbNo Then
            Cancel = True
            Item.Display
            Exit Sub
        End If
        If lngres = vbYes Then
            Cancel = True
            Item.Display
            Exit Sub
        End If
    End If
End Sub