The ID property is automatically assigned by the control once a new element is added. You can change the ID property to a different value, unless there is no other element with the same ID. In other words, the surface must contains elements with different IDs. The CreateElement event notifies your application once a new element is created. When elements are saved to an XML document using the SaveXML, the ID will be as string once the LoadXML method is called ( the XML file is a TEXT file )