//--------------------------------------------------//
        //--- Called when the add port button is clicked ---//
        //--------------------------------------------------//
        private void btnAddPort_Click(object sender, EventArgs e)
        {
            var port = new PhysicalInterfacePortsPort();
            var form = new PhysicalInterfacePortForm(_physicalInterfaceConnectors);

            if (DialogResult.OK == form.ShowDialog())
            {
                lvPorts.AddPort(form.Port);
                //if (_physicalInterfacePorts.Port == null)
                //    _physicalInterfacePorts.Port = new List<PhysicalInterfacePortsPort>();
                //_physicalInterfacePorts.Port.Add( form.Port );
            }
        }
 //---------------------------------------------------//
 //--- Called when the edit port button is clicked ---//
 //---------------------------------------------------//
 private void btnEditPort_Click(object sender, EventArgs e)
 {
     if (lvPorts.SelectedItems.Count > 0)
     {
         var form = new PhysicalInterfacePortForm(_physicalInterfaceConnectors);
         form.Port = (PhysicalInterfacePortsPort)lvPorts.SelectedItems[0].Tag;
         if (DialogResult.OK == form.ShowDialog())
         {
             lvPorts.SelectedItems[0].Tag = form.Port;
             lvPorts.UpdatePort(lvPorts.SelectedItems[0]);
             lvPortConnectors.Port = (PhysicalInterfacePortsPort)lvPorts.SelectedItems[0].Tag;
         }
     }
 }