Code

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
  Dim xw As New XmlWriter(fc)
  AddHandler xw.SerializeTag, AddressOf WriteTag
  xw.Options.CustomTagSerialization = False
  xw.Write("C:\test.xml")
End Sub

Private Sub WriteTag(ByVal sender As Object, ByVal e As MindFusion.FlowChartX.Xml.SerializeTagArgs)
  If TypeOf e.Object Is Box Then
    Dim b As Box = e.Object
    e.Representation = b.Tag.ToString()
  End If
End Sub

Private Sub fc_InitializeBox(ByVal sender As Object, ByVal e As MindFusion.FlowChartX.BoxEventArgs) Handles fc.InitializeBox
  e.Box.Tag = fc.Boxes.Count
End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
  Dim xr As New XmlReader(fc)
  AddHandler xr.DeserializeTag, AddressOf ReadTag
  xr.Options.CustomTagSerialization = False
  xr.Read("C:\test.xml")
End Sub

Private Sub ReadTag(ByVal sender As Object, ByVal e As MindFusion.FlowChartX.Xml.SerializeTagArgs)
  If TypeOf e.Object Is Box Then
    Dim b As Box = e.Object
    b.Tag = Integer.Parse(e.Representation)
  End If
End Sub