private string GeometryToXml(IGeometry geometry)
{
System.String elementURI = "http://www.esri.com/schemas/ArcGIS/9.2";
// Create xml writer
ESRI.ArcGIS.esriSystem.IXMLWriter xmlWriter = new ESRI.ArcGIS.esriSystem.XMLWriterClass();
// Create xml stream
ESRI.ArcGIS.esriSystem.IXMLStream xmlStream = new ESRI.ArcGIS.esriSystem.XMLStreamClass();
// Explicit Cast for IStream and then write to stream
xmlWriter.WriteTo((ESRI.ArcGIS.esriSystem.IStream)xmlStream);
// Serialize
ESRI.ArcGIS.esriSystem.IXMLSerializer xmlSerializer = new ESRI.ArcGIS.esriSystem.XMLSerializerClass();
xmlSerializer.WriteObject(xmlWriter, null, null, "geometry", elementURI, geometry);
return xmlStream.SaveToString();
}