private void ImportColumnGroupBase (XmlSchemaElement parent, XmlSchemaGroupBase gb)
{
foreach (XmlSchemaParticle p in gb.Items) {
XmlSchemaElement el = p as XmlSchemaElement;
if (el != null)
ImportColumnElement (parent, el);
else if (p is XmlSchemaGroupBase)
ImportColumnGroupBase (parent, (XmlSchemaGroupBase) p);
// otherwise p is xs:any
}
}